NYSGA 2016
88th ANNUAL
NEW YORK STATE GEOLOGICAL ASSOCIATION
FIELD CONFERENCE
JOINT CONFERENCE WITH FRIENDS OF THE GRENVILLE
“GEOLOGIC DIVERSITY IN THE NEW YORK METROPOLITAN AREA”
SEPTEMBER 30-OCTOBER 2, 2016
Hosts: Rutgers University-Newark and Hofstra University
Organizers: Alexander E. Gates and J Bret Bennington
Field Volume Editor: Alexander E. Gates
http://www.nysga-online.net/
SPONSORS OF THE CONFERENCE
NYSGA: Geologic Diversity in NYC

0: TECTONIC EVOLUTION OF THE WESTERN HUDSON HIGHLANDS, NEW YORK
Jeffrey R. Chiarenzelli
St. Lawrence University, Canton, NY 13617
David W. Valentino
Department of Atmospheric and Geological Sciences, State University of New York at Oswego, Oswego, NY 13126
Alexander E. Gates
Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ 07102
Matthew L. Gorring
Department of Earth and Environmental Studies, Montclair State University, Upper Montclair, NJ 07043
INTRODUCTION
The New York Geological Association field conference in 2001 was organized to be run in southern New York State and northern New Jersey. Although the field guide for the conference was published by the association, the decision was made to postpone the field conference due to the attacks that took place on September 11th that year. In the end, the field trips were not run that year. Between 2001 and 2006, a considerable amount of geologic mapping was complete in the western Hudson Highlands supported by new geochronology and geochemistry, so a field excursion was prepared for the 2006 National Geological Society of America meeting held in Philadelphia (Gates et al., 2006). That field trip was canceled due to low attendance.
Over the past decade, the authors of this field guide have continued to examine the rocks of the Hudson Highlands but also in the context of the rocks exposed in the southernmost Adirondacks. This field trip is a continuation of the trip and field guide that was prepared by Gates et al. (2001) but never held. With the integration of continued bedrock mapping in the western Hudson Highlands, coupled with new geochronology and geochemistry, our objective with this trip is to provide a general tectonic overview to support other field trips on basement geology being run during this field conference. With the heavy emphasis on basement geology this year, it’s worth noting that the NYSGA field conference is being run in conjunction with the annual field conference of the Friends of the Grenville.

0: TECTONIC EVOLUTION OF THE WESTERN HUDSON HIGHLANDS, NEW YORK

Meeting Point
This field trip begins at the upper parking lot for the Sterling Forest visitor center within the Sterling Forest State Park.

STOP 1.. Metavolcanic Lithofacies, Eagle Valley Road, Sloatsburg, NY
This outcrop contains inter-layered mafic, intermediate composition gneiss and granitic gneiss layers. All of the rock types are contain a penetrative foliation that is interpreted to be the regional S1. The folding of this foliation is associated with regional dextral transpression. This stop is located between two of the larger dextral shear zones. The assemblage of rock compositions inter-layered at the meter to sub-meter scale is interpreted to represent metavolcanic rocks.

STOP 2. Metasedimentary Lithofacies, Seven Lakes Drive, Sloatsburg, NY
The rocks at this stop include sillimanite-garnet-biotite gneiss, and graphite-pyrite bearing metapsammitic gneiss. The presence of sulfides accounts for the rusty weathered outcrop surface. The dominant foliation in this gneiss is the regional S1 with minor crenulations and open folds that are subparallel to mineral lineations. Gates et al. (2006) interpreted these rocks to represent low energy sedimentary deposits in a restricted marine basin.

STOP 3. Metasedimentary Lithofacies, Palisades Interstate Parkway, Doodletown, NY
An extensive sequence of inter-layered quartzite, semi-pelitic gneiss and pelitic gneiss outcrop at Stop 3 along the Palisades Interstate Parkway. The compositional layering most likely represents the compositional variation of the sedimentary protoliths. The pelitic layers contain biotite, garnet, sillimanite and K-feldspar, while the quartzite layers contain primarily recrystallized quartz and K-feldspar and garnets. Samples from this outcrop were analyzed to characterize the geochemistry of this unit, and one sample of quartzite was used for U-Pb geochronology. The results of this work is discussed above.

STOP 4. Granitic Gneiss of the Indian Hill Shear Zone, Route 17A, Tuxedo Park, NY
There are numerous outcrops of granitic gneiss along the west bound lanes of Route 17A (Figure 29). Stop 4 is a series of outcrops within the first kilometer along the road. This area is underlain by highly deformed granitic gneiss, and a complete cross section of the Indian Hill ductile shear zone (Allers et al., 2001). The granitic gneiss contains a steeply east dipping penetrative foliation defined by recrystallized planar aggregates of quartz, K-feldspar and plagioclase, with subhorizontal mineral lineations. In places, there is well developed S-C fabric, and relict feldspar grains forming asymmetric augen. Using oriented samples, kinematic analysis of these macroscopic structures reveals a dominant dextral shear sense. In places, the foliation is disrupted by minor leucosomes, forming asymmetric boudins (Figure 9) with the same shear sense. Commonly, there are amphibolite layers ranging from a few cm to a meter wide within the granitic gneiss. The amphibolite layers are internally foliated with boundaries that are parallel to the penetrative foliation in the granitic gneiss. One thicker layer has an array of granite-filled en-echelon veins that also consistent with dextral shear (Figure 30).

STOP 5. Granitic Gneiss and Pegmatite, Route 17A, Tuxedo Park, NY
Stop 5 is a series of outcrops that are on both sides of the west bound lanes of Route 17A. At this location, the granitic gneiss of Stop 4 is cross cut by a pegmatite that is several meters thick. The contact is well exposed on both sides of the highway, however for those of you that are allergic to poison ivy, it is recommended that you carefully cross the highway to view the pegmatite –granitic gneiss contact on the south side of the highway. The pegmatite contains typical K-feldspar and quartz in a addition to large hornblende crystals that form a nearly subhorizontal lineation that reflects growth direction. This location is where samples were collected for U-Pb zircon geochronology previously discussed in this field guide.

STOP 6. Calcsilicate Gneiss, Route 17A, Tuxedo Park, NY
The granitic gneiss is in sharp contact with calcsilicate gneiss between Stop 5 and 6 along Route 17A. The calcsilicate gneiss contains plagioclase, quartz, diopside and epidote in the prominent dark layers that are strongly foliated. Lighter layers are leucosomes of K-feldspar and quartz that are parallel to the penetrative foliation (Figure 31). In most places, and especially at this location, the calcsilicate gneiss occurs as a minor migmatite. Typically, the calcsilicate gneiss is inter-layered with other metasedimentary lithologies such as pelites, psammites and marble. But, this body is one of the thickest, reaching upward of several hundred meters and was traced for more than 5 kilometers to the northeast along the margin of the granitic gneiss. The foliation in this calcsilicate appears to be composite where S2 (gneissosity) has been transposed parallel to the local shear zone (S2).

STOP 7. Bare Mountain Granite, Ironwood Drive, Tuxedo Park, NY
A series of granite sheets underlie the hills on the north and south side of the Ironwood Drive valley (Figure 33). The sheets range in thickness from a few meters upward of several hundred meters. Note the serrated topography on the south flank of Hogback Mountain in the topographic map above. Each of the promontories on the side of the mountain is underlain by the more resistant granite. The granite at Bare Mountain is one of the thicker granite sheets. Excellent outcrops occur on the western flank of Bare Mountain and for those interested in a good climb it would be worth the time to scale the face to examine a cross section of the granite. However, the same granite is readily accessible along the dirt road that follows the power line. At this location, the granite is pink to white, leucocratic, containing quartz, K-feldspar and plagioclase with only trace amount of biotite or hornblende. In places, there are K-feldspar megacrysts upward of 10 cm in diameter. Although not exposed at this location, the contact with the local country rock is sharp, but the granite has a weakly to moderately developed mylonitic foliation.

Optional stop.
This is an outcrop of a smaller granite sheet. Refer to the 2003 NYSGA Guidebook, Appendix A, Trip A6, Stop 2 for details (Gorring et al., 2003).

A1: SEQUENCE STRATIGRAPHY, SEDIMENTOLOGY, AND PALEONTOLOGY OF THE UPPER CRETACEOUS NAVESINK FORMATION, NEW JERSEY
J. Bret Bennington
Department of Geology, Environment, and Sustainability, Hofstra University, Hempstead, NY 11549
INTRODUCTION
Overview of the Naves-ink Formation
The Navesink Formation is an 8 meter thick interval of fossiliferous glauconitic sand exposed along the eastern margin of the Cretaceous outcrop belt in New Jersey (Figure 1). At the northern end of the outcrop belt in Monmouth County, the Navesink Formation is accessible along the banks of Big Brook between Hillsdale Road and Boundary Road and along the banks of Poricy Brook, at Poricy Park on the Middletown-Lincroft Road. These two localities have long been known to fossil hunters as accessible places to collect Late Cretaceous marine fossils. Less widely appreciated is the fact that the Navesink Formation contains an excellent sedimentological record of the transition from an inner shelf to an outer shelf environment during a sea-level rise. The changes in environment that occurred with the changes in sea level are recorded in a sequence of sedimentary facies defined by distinctive suites of sediments, trace fossils, and macrofossils. Our objective on this field trip is to examine the various features that define each facies, as well as the characteristics of the transitions between facies. The explanations for the transitions between facies and the sequence stratigraphic interpretation of the Navesink are incompletely understood and provide opportunities for discussion and debate. Likewise, the mechanisms of shell bed formation in the upper Navesink remain an unsolved mystery – was the primary control on shell accumulation biological, sedimentological, or environmental?

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Meeting Point

STOP 1. Poricy Park Nature Center, 345 Oak Hill Road, Middletown, NJ 07748
The Poricy Park Nature Center is located on the grounds of the Poricy Park Conservancy, a 250 acre tract of open space – the largest in Monmouth County. The nature center features an exhibit showcasing the common fossils recovered from the Navesink Formation. As the rest of the field trip stops are not located far from the nature center, we can carpool from here to cut down on the number of vehicles at subsequent stops. Bathrooms are also available in the nature center.

STOP 2. Poricy Park Fossil Beds, Middletown, NJ
The Poricy Brook fossil locality is located in Monmouth County, NJ on the Middletown-Lincroft Road / Hwy 50. Fossil collecting is permitted within the rules stipulated by the park.
Sediments and Fossils
Only the uppermost section of the Navesink (Facies D – Figure 5 in the corresponding paper) is exposed at Poricy Brook. The upper shell bed is exposed at stream level and large specimens of Pycnodonte can be seen weathering out of the clayey glauconitic sands. Careful disaggregation of the shell bed sediments will reveal Agerostrea , Exogyra, and the brachiopod Choristothyris. Shell bed sediments also contain an abundant microfauna which can be extracted by soaking the sediment in household bleach for several days and then washing through a fine mesh to remove the clays. Careful examination of specimens of Pycnodonte will show that many contain faint red bands of original coloration preserved in the shell. In addition, most Pycnodonte record evidence of repeated predation attempts shown as irregular disruptions in the growth lines in the shell and displacements of the preserved color bands (Bennington, 2002; Bennington et al., 2000). Digging into the cut banks of the stream to obtain fossils is against the rules of the park, but I will try to obtain permission to collect some fresh specimens so we can observe the original shell coloration. Sieving the stream sediments will produce valves and fragments of the larger oysters as well as smaller specimens of belemnites, oysters, and brachiopods.

STOP 3. Big Brook Hillsdale Road Locality, Colts Neck, NJ
The Navesink Formation is exposed in cut banks along Big Brook in Monmouth County, NJ and can be accessed from the Hillsdale Road entrance to the Big Brook Nature Preserve. Fossil collecting is permitted within the rules stipulated by the preserve. Walk upstream from the bridge on Hillsdale Road to the first large cut bank.
Sediments and Fossils
This section exposes the middle interval of the Navesink Formation, from the top of Facies B at stream level to midway through Facies D (Figure 5 in the corresponding paper). The contact between Facies B and C can be clearly seen as a break in the slope of the cut bank wall about 30 cm from stream level. Belemnite guards are easy to find in the sediments directly above the contact. About midway up the cut bank wall is the lower shell layer containing articulated specimens of Exogyra costata. The upper shell bed is exposed near the top of the slope downstream from the bridge. Burrows in the upper interval of Facies B can be observed to have originated above in Facies C, piping the darker, more glauconite-rich, sediment of Facies C downward into Facies B. Specimens of the pectin Chlamys venustus can be observed in the lower interval of Facies C. The contact between Facies B and C, which we will also see at Stop 4, is interpreted by some researchers (e.g. Miller et al., 1999; 2004) to be a transgressive surface of erosion as evidenced by a sharp disconformity, reworked sandy sediment, and phosphate nodules. The increase in abundance of fossil from pelagic organisms, in particular belemnite squid quards, suggests a significant decrease in sedimentation rate across the Facies B-C boundary.

STOP 4. Big Brook Boundary Road Locality, Colts Neck, NJ
Here the Navesink Formation can be accessed via a path down to the stream on the southeast side of the bridge over Big Brook at Boundary Road. Fossil collecting is permitted within the rules stipulated by the Big Brook Preserve. Walk downstream from the bridge on Boundary Road observing the sediments exposed in the cut banks. Avoid going upstream of the bridge – this reach is bordered by private property on the north side of the stream and the landowner is hostile toward fossil collectors.
Sediments and Fossils
Walking downstream from the bridge, one can observe Facies A through Facies D (Figure 5 in the corresponding paper) in various locations along the stream banks. At stream level the callianassid burrows (Ophiomorpha) typical of Facies A weather out of the sediment in relief and their branching structure can be observed. Just above eye level the contact between Facies B and C is marked by a horizon of light, sandy blobs. Belemnite guards can usually be found weathering out of the sediment in the first meter above the Facies B-C contact. The Exogyra shell bed observed at the last stop is also present here, but it is difficult to access. Climbing the vegetated slope of a large slump at the first large cut bank downstream of the bridge allows access to the upper shell bed, although it may be covered by loose sediment. Although the fossiliferous lag that marks the sequence boundary at the base of the Navesink is below stream level at this location, weathering of this horizon farther upstream creates a steady supply of vertebrate fossils that are washed downstream. Sieving the stream gravels in the downstream vicinity of the bridge will produce a variety of shark teeth, as well as fish teeth and the occasional bone or tooth fragment from a marine reptile.

A2: HISTORICAL SEDIMENT CARBON ACCUMULATION RATES AND CURRENT ACCRETION PATTERNS IN THE MEADOWLANDS OF NEW JERSEY
Francisco Artigas, Joseph Grzyb and Michael Stepowyj
Meadowlands Environmental Research Institute
One DeKorte Park Plaza
Lyndhurst, New Jersey 07071
ABSTRACT
Historical carbon accumulation rates are preserved in the sediment stratigraphy of temperate macrotidal salt marshes. Tidal wetlands will most likely play a role as a source of carbon credits for a global carbon market (blue carbon) so estimating their long term carbon storage potential (i.e. greater than 100 years) and the marsh ability to persist over time is a necessary first step. If accretion rates are not keeping up with rising sea level there is a chance that these ecosystems could be completely inundated and lose their ability to capture carbon in the future. We analyzed the remaining carbon content in sediments using core samples and measured accretion rates and elevation change of marsh surfaces by performing Surface Elevation Table (SET) readings and feldspar marker readings over a 6 year period. Sediment core analysis shows a sharp increase in carbon accumulation rate that started around 600 years ago and reaches a maximum of 192.2 gr/m2/yr in the most recent layers. Measurement of surface and sub surface processes (i.e. accretion and subsidence) revealed that the average rate of marsh surface elevation change is approximately 4.6 mm/yr. The 60+ year rate of sea level rise established through tide gauge measurements in New York, Connecticut and Rhode Island average 2.6 mm yr-1. Based on these figures we conclude that under the current circumstances, marsh surfaces in the Meadowlands are out passing sea level rise or at least they are keeping up with sea level rise.
INTRODUCTION
Tidal marshes in glaciated northern New Jersey are connected with the retreat of the Wisconsin Ice sheet (15,000 yr. B.P), the creation of a post glacial lake Hackensack, the rise in sea level and entry of tidewater into the Hackensack valley which resulted in deposition of peat and muck over the glacier lake sediments (Heusser, 1949; Peteet, 1980). An apparent reduction in the rate of sea level rise from 3,000 to 2,000 yr B.P. (Stuiver and Daddario, 1963) is now linked to the earliest development of coastal peats (3.8 m deep) in the Hackensack valley. Evidence of this early colonization are the Alnus seeds and associated fresh water species dated to 2060 ±120 yr B.P. (Peteet, 1980) and basal peat formation over the same lake sediment dated to 2025±300 yr B.P. only a few Km away (Heusser, 1963). Palynology and peat stratigraphy evidence suggests marine transgressions and regressions, where established tidal marsh areas became sufficiently fresh water to support swamps containing alder and birch that later reverted back to marshland during marine transgressions (Heusser, 1963).
Tidal wetlands will most likely play a role as a source of carbon credits for a global carbon market so estimating their long term carbon storage potential (i.e. greater than 100 years) is a necessary first step (Freedman et al., 2009; Hansen, 2009). Moreover, solid baselines for accretion rates and quantifiable carbon flows would also be critical to any future CO2 emission reduction program. On the other hand, if accretion rates are not keeping up with rising sea level there is danger that these ecosystems could be completely inundated and lose their ability to capture carbon. Furthermore, there is a need for standardized methods for quantifying carbon sequestration and carbon storage baselines as concluded by Chumra (2003), Rocha and Goulden (2009), Crooks et al. (2010) and Moffett et al. (2010).
Historical carbon accumulation rates are preserved in the sediment stratigraphy of temperate macrotidal salt marshes (Allen, 2000). The rates of vertical accumulation depend on the type of plant community, sediment inputs, flooding regime, micro topography and autocompaction of the peat (Pethick, 1979; Stumpf, 1983). Studies in Delaware Bay, the lower Hudson Valley and Connecticut (Bloom 1964; Fletcher et al., 1993; Pederson et al., 2005, respectively) show that around 6000 yr. ago palustrine wetlands occupied the coastal valleys of the north eastern shore and that by ∼3000-2000 yr. B.P., the ongoing Holocene transgression created a variety of mud flats and subtidal environments and eventually the modern marsh, which is only a few hundred years old and holds the record of recent carbon sequestration rates (Pizzuto and Schwendt, 1997). The remaining carbon in the sediments not only accounts for carbon lost to the atmosphere through decomposition in the form of methane (CH4), carbon monoxide (CO) and volatile organic carbon (VOC) but also accounts for leaching of dissolved inorganic and organic carbon and lateral particulate carbon transfers.
Due to sea level rise, surface and sub-surface processes (i.e. accretion and subsidence) of tidal marshes is an important factor in maintaining the ecosystems’ ability to capture and store carbon. We analyze the accretion rate and elevation change of the meadowlands marsh ecosystems by performing Surface Elevation Table (SET) readings and feldspar marker readings. The SET is a leveling device measuring the relative elevation change of wetland sediments. These elevation readings allow us to see the buildup of the marsh in relation to rising seas. The shallow zone of subsidence contributes to the overall elevation of the marsh, as the subsurface processes in this zone counteract the increase in vertical accretion above the feldspar layer. Separating the vertical accretion surficial processes from the subsidence at depth is important in identifying different roles of the sediment column in marsh elevation dynamics. In this study we attempt to compare historical carbon accumulation rates by looking at carbon content in the sediment column and assess future carbon storage potential given local accretion rates and sea level rise forecasts.

STOP 1. Secaucus High School Marsh
Secaucus High School Marsh is location where we collect Surface Elevation Table (SET) readings. The SET is a leveling device measuring the relative elevation change of wetland sediments. These elevation readings allow us to see the buildup of the marsh in relation to rising seas, referencing a fixed subsurface datum. This process evaluates the surface processes at hand such as sediment deposition and erosion. Below the feldspar horizon is the zone of shallow subsidence, a stratigraphic zone extending down to the bottom of the SET rod. The shallow zone of subsidence contributes to the overall elevation of the marsh, as the subsurface processes in this zone counteract the increase in vertical accretion above the feldspar layer. Separating the vertical accretion surficial processes from the subsidence at depth is important in identifying different roles of the stratigraphic column in marsh elevation dynamics.

STOP 2. Riverbend Wetlands Preserve
To explore the total organic carbon remaining in the sediments of a natural marsh, 50cm increment peat cores to a depth of 5.5 m were extracted from the nearby undisturbed Riverbend Wetland Preserve (RWP) tidal salt marsh (N 40° 45’ 11.37”; W 74° 05’ 36.62”)

A3: CRYSTALLINE MEGABOUDINS ALONG THE LEADING EDGE OF THE TACONIC THRUST SHEET, ORANGE COUNTY, NY
Alexander E. Gates
Department of Earth & Environmental Sciences
Rutgers University
Newark, NJ 07102
As rocks are extended during deformation and break into fragments, they are termed boudins and the spaces between are gaps. However, in some geological settings, theses boudins can be quite large and are considered megaboudins or megalenses (Tricart and Lemoine, 1986). Typically, these terms were reserved for plate boundaries and highly active tectonic situations. However, large lenses of rock can form within actively deforming belts outboard of a plate boundary. This is the situation with the Monroe megaboudins of Orange County, southeastern New York which are the subject of this field trip.
The Monroe area encompasses parts of the western Hudson Highlands, an extension of the Reading Prong, the Valley and Ridge province and the Green Pond Outlier (Figure 1) (Offield, 1967; Jaffee and Jaffee, 1973; Gates and Valentino, 2000; Gates and Kush, 2007; Gates and Valentino, 2014). The Hudson Highlands are composed of 1.0-1.3 Ga Grenville ridge forming igneous and high grade metamorphic rocks of the Rodinian tectonic cycle (Gates et al, 2001; Gates et al, 2006; Gates and Valentino, 2014). The Valley and Ridge rocks in southeastern New York are composed of Cambrian to Silurian unmetamorphosed sedimentary rocks of the Pangean cycle (Rodgers, 1970; Gates and Valentino, 2014). The Green Pond outlier is a belt of unmetamorphosed Silurian-Devonian sedimentary rocks that are equivalent to the Valley and Ridge units but which occur within the Grenville rocks of the Highlands (Herman and Mitchell, 1991).
The Monroe megaboudins form a chain of small hills of 50-100 m elevation in an otherwise relatively flat terrain of +20 m relief (Figure 2). The megaboudins range in size from 50 m on an edge to as large as 1.2 X 3 km with northeast trending long axes parallel to the regional structural grain and the chain. There is no pattern to the size order. The gaps between the boudins are as large as 2 km but generally decrease towards the southwest. Jaffee and Jaffee (1973) interpreted the megaboudins to be klippe that were erosionally separated from the Highlands massif to the southeast but Gates (1996) showed that they are megaboudins. To the northwest, the area is completely underlain by shales of the Martinsburg Formation.

STOP 1. Traverse through the Museum Village megaboudin
OHM 2020: Coordinates in Guidebook are not correct.
Quartzofeldspathic gneiss with intense fracturing and alteration. The entire span of the megaboudin can be observed on the transect exposed in the Rt 17/6 road cut. Rock types and structures are observed near the Museum Village Rd overpass. The gneiss shows chlorite and hematite alteration on most fracture faces and the rock is altered throughout. Fracturing is more intense along the edges of the megaboudin and is multidirectional. Many surfaces exhibit both fibrous and polished slickensides that primarily show reverse motion but locally show many directions.

STOP 1a. Wappinger Group Limestone on the Museum Village megaboudin
Small outcrop of bedded Cambrian limestone with nodular chert layers. This rock lies unconformably above the gneiss. Note the lack of intense jointing seen in the gneiss and the gentle deformation. This is a small outcrop for reference. Limestone occurs both above and beneath the megaboudins because it is structurally repeated.

STOP 1b. Martinsburg Formation and view of the Goose Pond megaboudin
OHM 2020: Coordinates in Guidebook are not correct.
The Goose Pond megaboudin is the next south from the Museum Village megaboudin in the chain. It is located far to the west of the rest of the chain. This is because the E-W trending Monroe Fault offsets the megaboudin by approximately 1 mile in a dextral strike-slip sense. The Monroe Fault is interpreted as a Cretaceous fault but appears to be currently active with several recent epicenters located along its western extension. Several hundred feet west of the parking area are outcrops of Martinsburg shale. This shows the western contact of the Museum Village megaboudin is with lower Martinsburg Formation (Bushkill Member) and indicating a loss of section.

STOP 2. Bull Mine Mountain megaboudin
Bull Mine is a magnetite (iron) mine in the Bull Mine Mountain megaboudin. There are several adits and shafts within the mine complex and a tailings pile with large quantities of ore. The host gneiss for this iron deposit is largely metavolcanic gneiss but is also metasedimentary including calcsilicates. The mine is accessible and the dump contains a significant amount of ore. Farther along the western slope of the Bull Mine Mountain megaboudin, gneiss can be seen directly overlying Martinsburg shale in an overthrust contact. Both the gneiss and shale are highly fractured and contain slickensides showing thrust and reverse movement. The shale is highly cleaved and shows foliation and some bedding that dips beneath the gneiss.

STOP 3. View of Round Hill megaboudin
The Round Hill megaboudin has a saddle in the middle where it began to separate but never developed a gap. The gneiss is continuous across the megaboudin but at a much lower elevation where intense fracturing made it subject to erosion. From this location, the abrupt hill of the weakly to unfractured gneiss in the northern part of the Round Hill megaboudin can be seen in the other low lying shale plain. To the south of Round Hill Rd. the southern elevated part of the Round Hill megaboudin can be seen.
There are outcrops of Martinsburg shale along Round Hill Rd. and an abrupt contact with gneiss at the megaboudin saddle.

Possible stop on Rt 94 (if time permits)
Possible stop on Rt 94 (if time permits) to view Martinsburg Formation outside the influence of the megaboudins for comparison. Outcrop is beneath Railroad trestle.

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STOP 7: View of the megaboudin chain
The walk to the vantage point is on Bellvale Sandstone up Skunnemunk Mountain. Look to west to see the entire observed megaboudin chain sitting in the plain underlain by Martinsburg shale.

A4: PETROGENESIS AND TECTONICS OF PRE-, SYN-, AND POST-OTTAWAN GRANITOIDS OF THE WESTERN HUDSON HIGHLANDS, NY
Matthew L. Gorring
Department of Earth & Env. Studies
Montclair State University
Montclair, NJ 07043
Alexander E. Gates
Department of Geology
Rutgers University
Newark, NJ 07102
David W. Valentino
Department of Earth Sciences
SUNY-Oswego, Oswego
NY 13126
INTRODUCTION AND GEOLOGIC SETTING
The purpose of this field trip will be to examine the field relations, geochemistry, and geochronology of a diverse suite of pre-, syn-, and post-Ottawan (1090-1030 Ma) granitoid rocks exposed in the western Hudson Highlands, NY. These rocks are critically important for constraining petrogenetic processes and the tectonic history of the Grenville Orogen (1350-960 Ma) in the north central Appalachians. The Hudson Highlands, along with the physically contiguous New Jersey Highlands and similar rocks extending into eastern Pennsylvania, are collectively called the Reading Prong, one of the largest of several Grenville-age (∼1350 to 1000 Ma) basement massifs within the core of the Appalachian orogenic belt of eastern North America (Figs. 1 and 2; Rankin, 1975). These basement massifs lie outboard (east) of the main Grenville Province in eastern Canada and record variable amounts of post-Mesoproterozoic metamorphic and deformational overprint (e.g., Rankin et al., 1989; Gates and Costa, 1998). The Reading Prong displays evidence of only brittle deformation concentrated along narrow, reactivated Mesoproterozoic shear zones due to late Paleozoic compression and Mesozoic rifting (Gates, 1995; 1998) and thus, have a well preserved record of Grenville-age metamorphism and deformation. Rocks of the Hudson Highlands consist of a complex assemblage of metasedimentary, metavolcanic, and quartzofeldspathic (“granitic”) gneiss, and intrusive granitoid rocks that were variably deformed and metamorphosed at upper amphibolite to hornblende-granulite facies conditions during at Grenville orogenesis (Dallmeyer and Dodd, 1971; Dallmeyer, 1974; Helenek and Mose, 1984). Based on field relations and recent SHRIMP U-Pb zircon ages (Ratcliffe and Aleinikoff, 2001; Gates et al. 2004; Volkert et al., 2005; Volkert et al., 2010; Aleinikoff et al., 2012), rocks of the Hudson Highlands, and the contiguous New Jersey Highlands can be roughly divided into two groups: (1) pre-Ottawan (>1060 Ma) and (2) syn- to post-Ottawan (<1060 Ma). Pre-Ottawan rocks all have strong, penetrative, high-grade metamorphic fabrics related to the Ottawan orogeny. Syn- to post-Ottawan rocks are variably deformed, ranging from undeformed to those that locally have strong, high grade, ductile fabrics but lack the regional-scale, penetrative fabrics that characterize the pre-Ottawan rocks. Locally, syn- to post-Ottawan rocks truncate fabric elements in pre-Ottawan rocks. The area of the field trip is located in parts of the Sloatsburg and Popolopen Lake quadrangles west of the Hudson River within the west central Hudson Highlands, New York (Figs. 2 and 3). Previous mapping in this area, divided the units by rock types (Dodd, 1965; Jaffe and Jaffe, 1973; Dallmeyer, 1974; Helenek and Mose, 1984).

A4: PETROGENESIS AND TECTONICS OF PRE-, SYN-, AND POST-OTTAWAN GRANITOIDS OF THE WESTERN HUDSON HIGHLANDS, NY

Meeting Place

STOP 1. Bear Mountain, NY
The next series of sub-stops will require a moderately strenuous hike (∼5-6 miles roundtrip; 600 vertical feet of elevation change) mostly along the Appalachian Trail and the Perkins Memorial Drive (paved) to the summit of Bear Mountain. On the way, we will examine very nice exposures of not only the Canada Hill granite and Storm King granite gneiss, but also take the opportunity to look at outcrops of the “rusty” metapelitic gneisses of the Metasedimentary Lithofacies and the quartz-plagioclase-biotite-Opx (“charnockitic”) gneiss of the Metavolcanic Lithofacies. We will examine the field relations between these units and discuss the current U-Pb zircon age constraints and whole-rock geochemical data to understand the petrogenesis and implications for Grenville tectonics in the region. Bring food and water. We will be out all morning and will have lunch at the summit of Bear Mountain.

STOP 1a
The first of several stops during our hike is a very nice roadcut exposure of the “rusty” metapelitic gneiss unit of the Metasedimentary Lithofacies. The distinctive “rusty” weathering of this unit is from the alteration and breakdown of accessory Fe-sulfides (pyrite and/or marcasite?). At this locality, the metapelite has a fairly common assemblage of garnet-biotite-quartz-K-feldspar ± plagioclase ± sillimanite and has a strong foliation that is moderately NE-dipping. Metamorphism is of hornblende granulite facies and maximum P-T estimates are on the order of 700-750ºC and 4±1 kilobar based on mineral assemblages in metapelitic and mafic metavolcanic units (Dallmeyer and Dodd, 1971). Deformation and metamorphism associated with this event is most likely of Ottawan age.

STOP 1b.
On the southwest flanks of Bear Mountain along the Appalachian Trail there are a series of excellent natural outcrops of the quartz-plagioclase-biotite-Opx (“charnockitic”) gneiss of the Metavolcanic Lithofacies with a strong foliation that is moderately NE-dipping. We will make a quick stop to examine one of these outcrops. These rocks are significant because they presumably the oldest rocks in Hudson Highlands. Based on a U-Pb SHRIMP zircon core ages ranging from ∼1360-1250 Ma (Volkert et al., 2010) on the correlative Losee Metamorphic Suite rocks in the NJ Highlands and whole-rock geochemical analysis (Volkert and Drake, 1999; Gorring et al., 2001; Volkert et al. 2004) these rocks represent a calc-alkaline, continental arc suite related to subduction off the eastern margin of Laurentia during the Elzevirian Orogeny.

STOP 1c.
At this locality, there is a spectacular, glacially plucked outcrop of the distinctively blue-gray to white, leucocratic Canada Hill granite that is commonly found in the Bear Mountain area and extending northeastward into the West Point and eastern Hudson Highlands region. The Canada Hill granite at this locality is a coarse- to very coarse-grained equigranular rock composed of quartz, K-feldspar, plagioclase, and biotite ± garnet. It forms a sheet-like body ∼15-20 m thick and ∼300-400m in length that has concordant contacts with the surrounding metavolcanic “charnockitic” quartz-plagioclase-biotite-Opx and “rusty” metapelitic gneisses (Fig. 10). Foliation in the surrounding gneisses is moderately NE-dipping (∼N45W, 40NE). The contact between the Canada Hill granite and the “charnockitic” gneiss is well exposed for about ∼100m along strike where small rafts and xenoliths of “charnockitic” gneiss are observed within the Canada Hill granite. Similar crosscutting relations have been documented elsewhere in the Hudson Highlands. For example, Helenek and Mose (1984) and Ratcliffe (1992) observed the Canada Hill granite cutting gneissic fabric elements within the Storm King granite gneiss, metapelitic, and metavolcanic rocks in the Popolopen Lake and Oscawana Lake quadrangles to the south and east. In the Bear Mountain area, Helenek and Mose (1984) found xenoliths of Storm King granite gneiss enclosed in Canada Hill granite along the southern margin of the Brooks Lake Pluton. Helenek and Mose (1984) also noted a weak axial planar foliation and the location of Canada Hill granite in the hinges of large-scale, broad, open, upright, plunging folds (e.g., Bear Mountain synform) and interpreted this to indicate that the Canada Hill Granite was syntectonic to and slightly deformed during a late-stage Grenville orogenic event. Based on a recent U-Pb SHRIMP zircon core age of 1058 ±14 Ma (Aleinikoff et.al., 2012) and whole-rock geochemical analysis (Kulick and Gorring, 2004), the Canada Hill Granite represents a syn-tectonic, S-type granitoid produced by partial melting of metapelitic gneisses and emplaced during the Ottawan Orogeny (Fig. 5 and 8C).

STOP 1d.
Roadcuts along Perking Memorial Drive on the southwest side of Bear Mountain expose excellent examples of the Storm King granite gneiss. Here, the Storm King is a coarse-grained, quartz-K-feldspar-plagioclase-hornblende gneiss that is strongly lineated (L>S) rock (Fig. 11). The fabric is defined by stretched hornblende prisms and rodded quartz-feldspar aggregates interspersed with large (2-4 cm) plagioclase and/or K-feldspar augen. Based on U-Pb SHRIMP zircon age of 1174 ±8 Ma (Ratcliffe and Aleinikoff, 2001) and whole-rock geochemical analysis (Verrengia and Gorring, 2002), the Storm King granite gneiss is interpreted to represent a pre-Ottawan., A-type granitoid produced by partial melting of intermediate igneous source rocks during an early stage of AMCG-related lithospheric thinning that affected this part of the Grenville Orogen (Fig. 4A, C and Fig 8B).

STOP 2. Lake Tiorati, NY
We will examine the field relations and chemistry of a sheared mafic granitoid, referred to as the Lake Tiorati Diorite at its type locality near the eastern margin of the Fingerboard Mountain Shear Zone (Gates et al., 2001c; 2004). This particular outcrop is part of a relatively large body of Lake Tiorati Diorite that is ∼200-300 m thick and is ∼5-6 km in length located on the west side of Lake Tiorati (Fig. 12A). At the southern end of the outcrop, the rock is essentially undeformed with igneous texture (Fig. 12C). The diorite is composed mostly of plagioclase, hornblende, and clinopyroxene with minor orthopyroxene, magnetite and ilmenite. The orthopyroxene occurs as brown cores surrounded by coronas of clinopyroxene and/or hornblende. There is also a large xenolith of well-foliated biotite-plagioclase-quartz (metasedimentary) gneiss in the upper part of the outcrop. In the central and northern parts of the exposure, the diorite is cut by several anastomosing mylonite bands (Fig. 12 B). The mylonite here is part of the Fingerboard Mountain Shear Zone which is one of several late- to- post-Ottawan ductile shear zones that occur in the western Hudson Highlands (Figs. 3 and 13A) that were mapped and described by Gates et al. (2004); the details of which will be the subject of trip B-3 on Sunday, October 2, 2016, led by Michael Kalczynski and Alexander Gates. U-Pb SHRIMP dating of small, subhedral zircons with minimal zoning from the undeformed diorite from this outcrop yielded a cluster of concordant ages averaging 1008 ±4 Ma (Fig. 6). Since this body is clearly cut by ductile shear zones, this age provides an upper limit on the ductile deformation event that produced the mylonitic fabric. Whole-rock major and trace element chemistry of samples from this outcrop indicate a mafic (∼50% SiO2, see Table 1) calc-alkaline, arc-like affinity for these rocks (Figs. 7A and C). We interpret the arc signature in these rocks to have been inherited from the continental lithosphere during magma generation and emplacement, and thus they do not indicate that there was active subduction zone in this part of the Grenville at the time. Based on field relations, geochronology, and geochemistry, the Lake Tiorati Diorite is best interpreted as a post-Ottawan mafic plutonic rock that was emplaced just prior to or synchronously with a major ductile shearing event that occurred ∼1000 Ma (Fig. 8D).

STOP 3. Indian Hill Shear Zone, road cuts on NYS 17A
Road cuts on north side and in median of NY Rte 17A afford an excellent view of a post-Ottawan pegmatitic granite dike that cuts mylonitic quartzofeldspathic gneiss (correlative to Storm King granite gneiss). The mylonite here is part of the Indian Hill Shear Zone which is one of several late- to- post-Ottawan ductile shear zones that occur in the western Hudson Highlands (Fig. 3 and 13A) that were mapped and described by Gates et al. (2004) and the details of which will be the subject of trip B-3 on Sunday, October 2, 2016, led by Michael Kalczynski and Alexander Gates. The pegmatitic dike is ∼2-3 m thick, vertical dike that is composed of coarse-grained granite with large crystals of hornblende that form radiating and linear aggregates. It is exhibits no deformation fabric and cross-cuts the mylonite at a high angle, and thus clearly postdates the ductile deformation of the quartzofeldspathic gneiss (Fig. 13B). Unfortunately, there are no radiometric age constraints or geochemical data for this particularly pegmatite dike, but field relations, texture, and mineralogy of this dike are very similar to pegmatitic granite dikes from the NJ Highlands (Volkert at al., 2005) and elsewhere in the Hudson Highlands (Grauch and Aleinikoff, 1985) that have U-Pb zircon ages in the range of ∼1000 to ∼960 Ma. Volkert et al. (2005) reported that NJ Highlands pegmatites are dominantly metaluminous, have fractionated A-type geochemical affinities, and share characteristics of the niobium–yttrium–fluorine (NYF) class of pegmatites of Cerny (1992). These late pegmatite dikes are interpreted to have been emplaced during a period of post-orogenic extension that significantly postdates the gravitational collapse of the Ottawan Orogeny and the late- to post-Ottawan, high-grade, ductile transpressional events (Fig. 8D).

STOP 4: Sterling Forest Granite Sheets, road cuts on Long Meadow Road (CR 84)
This roadcut along northwest side of Long Meadow Road exposes a fine example of the syn-Ottawan Sterling Forest granite sheets found in the western Hudson Highlands (Fig. 14). These pink granite sheets are very leucocratic (∼75 wt% SiO2) (Appendix Table 2), composed of almost entirely quartz, K-feldspar, and plagioclase, with only small amounts (<5%) of hornblende ± biotite with accessory apatite, titanite, and zircon. At this locality, the sheet has a medium-grained, equigranular igneous texture and shows no evidence of deformational fabric. However, locally these granite sheets are foliated where intersected by late-stage, ductile shear zones and thus, are clearly pre- or syntectonic with the shearing event. This particular sheet is one of several, 10-100 m thick, finger-like bodies that extend both southward and northward several kilometers from the main plutonic masses at Hogback Mountain (to the north) and Bill White Mountain (to the south). Here, the sheet is about 20 m thick, strikes N20E and dips ∼65 to the southeast and has intruded parallel to foliation in the surrounding gneisses. It intrudes amphibolites and intermediate gneisses of the metavolcanic unit (contact observed at the north end of the outcrop) and metapelitic gneisses of the metasedimentary lithofacies. The granite sheet exposed here (sample SF-28) has a distinctly “dished” MREE pattern, a moderately strong negative Eu anomaly (Eu/Eu* = 0.35), high HREE contents (∼20x chondritic) and very low Ba and Sr concentrations (∼20 ppm) (Fig. 5C and Appendix Table 2). These chemical characteristics indicate that amphiboles and feldspars were important phases in the petrogenesis of this particular granite. The data is consistent with partial melting of garnet-free, mafic amphibolitic source rocks and/or fractional crystallization of amphibole + plagioclase ± K-feldspar at shallower crustal levels. The Sterling Forest granite sheets represents a syn-tectonic, I-type granitoid produced by partial melting of mafic/intermediate igneous sources and were emplaced during the Ottawan Orogeny (Fig. 5 and 8C).

A5: STRATIGRAPHY, STRUCTURE, AND TECTONICS OF NEW YORK CITY AS VIEWED THROUGH ITS PARKS
Charles Merguerian
Professor Emeritus
Geology Department, Hofstra University
Hempstead, NY 11549
Research Fellow
Yale University, New Haven CT 06520
Principal
Duke Geological Laboratory
Stone Ridge. NY 12484
J. Mickey Merguerian
Geologist
Stone Ridge, NY 12484
Geological Setting
NYC is situated at the extreme southern end of the Manhattan Prong (Figure 1), a northeast-trending, deeply eroded sequence of metamorphosed Proterozoic to Lower Paleozoic rocks that widen northeastward into the crystalline terrains of New England. Southward from NYC, the rocks of the Manhattan Prong plunge nonconformably beneath predominately buried Mesozoic rocks, younger Cretaceous strata, and the overlying Pleistocene drift found capping much of the region including all of Long Island and much of Staten Island. This NYSGA paper and allied Trip A-5 field guide are intended to prepare and expose participants to our subdivisions of the venerable Manhattan Schist into three separable units by utilizing exposures in NYC parks including Isham, Inwood Hill and Central parks.
Previous Investigations
A detailed history of NYC bedrock investigations appears elsewhere (Merguerian and Sanders 1991) so the following is simply a brief excerpt and overview. In 1890 (p. 390), Merrill named the Manhattan Schist for the micaceous metamorphic rocks found on Manhattan Island and suggested, following the views of Professors W. W. Mather (1843) and J. D. Dana (1880), that they represent metamorphosed equivalents of the lower Paleozoic strata of southern Dutchess County, New York. Merrill (1890) confides that "the name Manhattan Group was proposed by naturalist R. P. Stevens, Esq., to include the rocks of New York Island".
Despite this acknowledgement, Merrill and others (1902) produced the United States Geological Survey New York City Folio (#83) and following Dana chose to use the name Hudson Schist (rather than Manhattan Schist) for the schistose rocks of NYC. This pioneering work by Merrill and coworkers set the stage for a series of detailed investigations by many geologists in the 1900's that helped define the details of NYC bedrock units and use of the term Manhattan Schist as the name locality for the unit. Merrill also extended "Group" status to include the Manhattan Schist, the Inwood "limestone" and the Fordham and Yonkers gneisses and correctly correlated the Fordham with Proterozoic sequences of the Hudson Highlands. Formal removal of the significantly older Fordham and Yonkers gneisses from the "Manhattan Group" had to await the refinement and application of radiometric dating techniques and detailed mapping in the 1960's by Leo M. Hall (1968a; b). Formal "de-Grouping" of the "Manhattan Group" took place after spirited debate at a Symposium on the New York City Group of Formations at the 1968 meeting of the New York State Geological Association at Queens College, Queens, New York. Our studies of the metamorphic rocks of NYC since 1972 have benefited from these early works and access to surface and subsurface construction sites.

A5: STRATIGRAPHY, STRUCTURE, AND TECTONICS OF NEW YORK CITY AS VIEWED THROUGH ITS PARKS

Isham Park
Today’s field trip will start where bedrock is exposed in northernmost Manhattan in Isham and Inwood Hill parks (Figure 1). Northern Manhattan boasts the highest natural point of elevation at +265.5’ achieved atop rocky ridges in Bennett Park. The rocky ridges rise abruptly above the lowland plain to the east underlain by Inwood Marble. The adjacent prominent ridges are underlain by the venerable Manhattan Schist (OZm). Our analysis of the area departs a bit from published work in that we recognize schistose rocks in Manhattan aside from the Manhattan Schist. Indeed, in Inwood Hill Park representatives of all three ductile fault bounded schistose units can be found (Walloomsac [Ow], Manhattan [OZm] and Hartland [OCh] formations).
A cut-away cross-sectional view of northern Manhattan appears on a Google Earth basemap in Figure 2. Note the interpretation of the structure suggesting that the rocky ridges of northern Manhattan are controlled by overturned synforms of Manhattan Schist rooted by a major shear zone known as the St. Nicholas thrust which cuts both the Inwood Marble (OCi) and locally, the Walloomsac Schist (Ow). Below the flat plains of northeastern Manhattan, the Inwood is folded upward to the earth’s surface and beveled above two eroded F3 antiforms cored by Fordham Gneiss and an intervening F3 synform with all folds and most associated fabrics overturned toward the NW.
Isham Park contains near continuous exposure of white to blue-white Inwood Marble cut by high-angle conjugate joints which have facilitated the weathering process by allowing aqueous solutions to permeate the rocks (Figure 3). Several lithologies occur such as dolomitic marble, calcite marble, and foliated calc-schist, units that contain siliceous layers and calc-silicate aggregates that stand in relief on the weathered surface (Figure 4).
Depending on the amount of impurities the Inwood Marble weathers gray or tan and produces a sugary-textured surface on outcrops that ultimately develops into residual calcareous sand. Overall, the outcrops illustrate profound differential weathering with dolomite-silicate units standing in higher relief and calcite marble forming local depressions. With a bit of imagination, an overview of the entire outcrop at Isham Park allows a vision of mini-karst-like topography. Perched on this eroded surface are a number of Palisades diabase erratics and red-colored till, products of glacial advance from the NW.
A preliminary geological map of Isham Park is shown as Figure 5. Four major lithotypes are shown – white, coarse-textured calcite marble, white to gray dolomitic and calcite marble, marble, schist and calc-silicate rock and well-layered white to gray dolomitic marble. Although variable, the Inwood trends roughly N55°E, 73° SE in Isham Park and forms the eastern overturned limb of a large F3 synform which is cored to the west in Inwood Hill Park by the Manhattan Schist.
The marble, schist, and calc-silicate unit is intensely sheared and internally deformed by F2 tight- to isoclinal and F3 asymmetric folds producing complex interference patterns, boudinage and internal shearing of schistose boudins over a meter in dimension (Figure 6). Clearly, the marble + schist + calc-silicate sub-unit shows over-thickening and repetition of layers however most of the remaining carbonate sequence exposed in Isham Park appears to be homoclinal. Perhaps the over-thickening of the calc-schist unit is the result of the buttressing effect of the massive, well-layered marble that surrounds it. Asymmetric south-plunging F3 folds are locally developed in the Inwood of Isham Park (Figure 7). Abundant examples of boudinage of the quartzite and calc-silicate layers into lenses occur presumably the result of ductility contrast between the more competent siliceous rocks and the surrounding marble (Figure 8).
The broad outcrop-scale folding and warping of the S1 x S2 fabric is controlled not only by regional F3 folds but also are affected by open 2 m-wavelength SE-plunging F4 crenulate folds and open warps (∼ 55° plunge) with axial planar slip cleavage (S4), solution cleavage and joints trending ∼ N-S bearing moderate to steep dips.

Inwood Hill Park
The area of Manhattan north of Dyckman Street is known as the Inwood section. Except for Inwood Hill Park most of the region is underlain by the Inwood Marble marking the type-locality for that particular unit of NYC bedrock. This unit was originally called the Inwood Limestone by Merrill (1890). The geology of Inwood Hill Park is published elsewhere (Merguerian and Sanders 1991; Merguerian et al., 2011) but a brief summary is in order. Inwood Hill Park is located in the extreme northwest corner of Manhattan Island (Figure 22). The park is bordered by Dyckman Street on the south, the Hudson River on the west, Spuyten Duyvil (Harlem Ship Canal) on the north, and Payson and Seaman Avenues on the east. Isham Park occupies the flat area northeast of Inwood Hill Park extending eastward to Broadway between Isham and West 214th Streets.
We enter Inwood Park by following the path past the playground. The first prominent ridge to your left is composed of Manhattan Schist (OZm) which also dips steeply toward the SE, essentially parallel to the orientation of the Inwood Marble exposed in Isham Park. The S3 foliation in the schist is related to F3 folds with axial surfaces oriented N4l°E, 75°SE and south-plunging hinge lines. The F3 structures are superimposed on an older gently inclined S2 metamorphic layering which trends across Manhattan at roughly N50°W, 25°SW (Merguerian, 1983; 1996a). Both units are in contact but the contact is covered with soil. They form part of a huge south-plunging syncline with the Manhattan Schist preserved in the central core of the structure (Figure 10).
Strangely, the downfolds (synclines) hold up ridges and the upfolds (anticlines) underlie the flat valleys in northern Manhattan. Such inverted topography results from the marked contrast in weathering susceptibility afforded by the marble and schist. In the overall wet temperate climates such as we experience in this region, carbonate rocks (such as the Inwood Marble) weather and dissolve much more readily than do silica-rich rocks of the Manhattan Schist. As a result, structural synclines tend to be preserved to form topographically high ridges and structural anticlines are breached by weathering and erosion and commonly underlie the low valleys. (See Figure 2.) Such topographic inversions are well known in the folded central and northern Appalachians.

Glacial Potholes
Take the “high-road” path going southward to examine the dual potholes drilled into the east-facing slope of the westernmost synclinal ridge. The structure of the westernmost ridge is another south-plunging syncline overturned toward the northwest. (See Figure 10.) The S3 foliation in the Manhattan schist has transposed earlier fabrics and is associated with tight isoclinal F3 folds south-plunging hinge lines and axial surfaces oriented N41°E, 75°SE. At the north end of this ridge, we'll see the S2 foliation change trend from NE to NW to wrap around the synformal trough.
At the top of the trail, a bonus for glacial enthusiasts, two circular potholes produced by torrents of meltwater during the Pleistocene deglaciation are found (Figure 11). Clearly the potholes are cut into an already glacially polished rock outcrop. Here, we assume that resistant glacial drift boulders settled into a small depression (perhaps in ridge hugging drift) and then began to drill downward in response to vortices produced during turbulent flow from liberated glacial melt waters. A self-fulfilling prophesy, once the drilling begins the resistant boulders are trapped and constantly replenished by new boulders moved by water. In this case (Figure 11) the upper pothole merged to drill a second adjacent pothole. Since the potholes are developed on a sloping glaciated surface (pre-Woodfordian?), it may be tempting to envision that the potholes formed during a younger glaciation (Woodfordian?).
Farther up at the top of the trail past the potholes but before the trail bends into a hairpin turn to the right, note the highly polished outcrop of Manhattan Schist (Figure 12). The glacial striae and grooves are oriented N35°W to S35°E indicating the same glaciation that brought Palisades boulders from New Jersey. Sanders and Merguerian (1998) suggest this glaciation (from the NW to SE) was responsible for most of the deep glacial erosion in the NYC area and produced the prominent Harbor Hill moraine that extends across Staten Island, Brooklyn, Queens, and Long Island.

To Scenic Overlook of Hudson River
Continue up the trail on top of the westernmost ridge and jog left after awhile to get to the fine overlook across the Hudson to the Palisades ridge of New Jersey (Figure 13). Here, the columnar joints of the Palisades ridge are quite visible forming a steep wall of mafic rock that was intruded at shallow depth during the late Triassic-Early Jurassic split up of Pangea. Thus, we view across the Hudson, the products of a totally different type of tectonic activity than we have been viewing today. The metamorphic rocks of New York City were produced during deep-seated compressive deformation while the sedimentary and igneous rocks of New Jersey were produced by extensional tectonics associated with initial formation of the Atlantic Ocean basin. A cross sectional view from Manhattan to central New Jersey (Figure 14) shows that the entire Newark Basin is a rotated block of the earth’s crust with downward motion and westward tilting accommodated along the Ramapo fault. In this way the ancient Newark Basin is analogous to the modern rift basins of East Africa.
From the scenic overlook walk northward along trail toward the Henry Hudson Bridge and note that the foliation in the schistose rocks is oriented northwesterly and dips southward at the end of the trail before it heads downward. As mentioned earlier, this is the result of the wrapping of the early S1 x S2 foliation in the schist about the southward-plunging keel of the overturned F3 synform that holds up the westernmost ridge.
The contact between the middle and lower schist units (the St. Nicholas thrust) is exposed in a 20 m zone from beneath the Henry Hudson Bridge abutment to river level. Structurally beneath the Manhattan Schist, a 0.5 m layer of sheared (mylonitic) amphibolite is deformed by folds. Unlike the amphibolite in the schist unit above, which contains subidioblastic hornblende, this exposure of Manhattan amphibolite has been intensely sheared. Green hornblende porphyroclasts are set in a wavy, anastomosing foliation consisting of colorless amphibole, biotite, and quartz ribbons. The thrust zone is structurally complex consisting of intercalated lithologies of Walloomsac (Ow) and Manhattan Schist (OZm) together with mylonitic amphibolite. The Wallomsac is highly flattened and mylonitic at this location with a strong down-dip lineation, the result of localized shearing associated with the St. Nicholas thrust zone.

Marble with calc-silicate nodules
Directly beneath the bridge, where a dirt trail leads down to the river, a coarse-textured gray-white calcite marble with differentially eroded calc-silicate nodules is exposed at low tide. It is unknown whether the marble exposed at the low-tide mark is an interlayer in the Walloomsac schist (Ow) or the Inwood Marble (OCi). Unquestionably, the Inwood Marble lurks nearby as it wraps around the westernmost ridge of Manhattan Schist and underlies the Spuyten Duyvil, Marble Hill in the Bronx, and the Hudson River and was penetrated by a utility tunnel found east of and parallel to the Broadway Bridge. As a geometric result of the southward plunge of the major folds, the oldest unit of the NYC bedrock (Fordham Gneiss) projects up to the surface in the Bronx in a huge vertical exposure immediately across the Harlem Ship Canal. Here, in the Bronx, the Fordham is painted blue with the Columbia University “C”.

STOP 1. SE of Zoo work shed, Hartland formation.
OHM 2020: The UTM coordinates in the Guidebook have been corrected to WGS 84.
The exposure consists of gray- and locally brown-weathering muscovite-biotite schist and thin interlayers of biotite granofels, rocks typical of the Hartland formation (OCh) in New York City. The S2 foliation, which predominates at this exposure, consists of parallel thin laminae and local syntectonic granitoid veins oriented N80°W, 34°SW. F3 z-folds are also obvious with traces of axial surfaces oriented N42°E, 88°SE and F3 axes plunging 35° into S17°W. Abundant pegmatite veins (some with large books of muscovite) and veinlets create a nubby weathering appearance, but should not be confused with the aluminosilicate-induced nubby weathering of the OZm unit of the Manhattan Schist. Some of the pegmatite veins have been folded by the F3 folds. Local 10-cm thick quartzose segregations are present. An amphibolite, 15 cm thick, can be found at the south end of the exposure near 63rd Street.
Evidence for SE-directed glacial flow is obvious in the glacially sculpted exposure in the form of large- and small grooves oriented N30°W to N35°W wrapping around the south end of the exposure and at an azimuth of N40°W on top of the exposure.

STOP 2. Mylonitic Hartland formation cut by glacial grooves.
E of walkway just N of 65th Street Transverse Road
OHM 2020: The UTM coordinates in the Guidebook have been corrected to WGS 84.
The exposures of Hartland here consist of slabby, gray-weathering vitreous quartzite layers (thicknesses usually 4 to 5 cm, but locally up to 30 cm), granofels, minor schist and amphibolite with a laminated fabric developed parallel to a composite S2 foliation. S2, subparallel S1 and bedding (S0), are strongly transposed (oriented N56°E, 45°SE) because of the effects of F3 z-folds with axial surfaces trending N50°E, 85°SE. The F3 folds and associated lineations plunge 24° into S21°W. Away from the limbs of minor F3 folds, at the NE corner of the first exposure, the S2 fabric returns to its typical orientation, roughly N53°W, 28°SW. Pegmatites, up to 2 m thick, containing K-feldspar megacrysts up to 30 cm in size, have been intruded parallel to S3 . Vertical healed joints cut the exposures at a high angle (N42°W) and show positive relief producing a reticulate pattern with the dominant lithologic layering and parallel metamorphic fabrics.
All of the scattered outcrops show the effects of glacial rounding and polish. Glacial grooves are oriented N47°W to S47°E; they resulted from ice flowing toward the SE.

STOP 3. Mylonitic Hartland formation and glacial grooves
OHM 2020: The UTM coordinates in the Guidebook have been corrected to WGS 84.
E of walkway near "X" crossing of paths S of "The Dene;" .
Similar to the last exposure (still in view toward the S), here the Hartland possesses a pronounced mylonitic fabric because we are approaching Cameron's Line. The composite S2 + S3 foliation is oriented N70°E, 49°SE (the combined effect of transposition by F3 fold and late warps) and has been intruded by numerous foliated lit-par-lit granitoids. In fact, two generations of granitoids cut the bedrock: 1) an older foliated generation, as mentioned above, and 2) a younger sinuous granitoid that cuts across the metamorphic layers.
Glacial grooves are here oriented N25°W to N32°W; they are products of a glacier that flowed SE.

STOP 4.Two sets of cross-cutting glacial features on polydeformed Hartland formation.
Outcrop W of "The Dene"
This large polished exposure contains rocks similar to the last three stops and shows the effects of superposed F2 and F3 folds. The composite S2 + S3 foliation is oriented N53°E, and is vertical (90°) or dips steeply SE. The bedrock has been cut by two generations of healed fractures, an older one trending N40°W and a younger one, N-S.
Obscured by post-glacial weathering on the E end of the exposure a partial pothole greets the observant student of geology. Nearby, glacial grooves are oriented N35°W again, supporting our earlier observations, indicating a SE-directed glacial ice-flow direction. At the NE end of the exposure a glacial treat awaits our eyes. Here, a subdued roche-moutonnée structure oriented N37°E is cut by N36°W-trending glacial grooves. Thus, one of our older glacial advances has left its indelible mark on the bedrock. (See Table 1.)

STOP 5. Beginning of the Cameron's Line shear zone, and glacial features
By "Platform" (outcrop E of "The Dene" and N of playground)
At this exposure, we will try to convince you that deep-seated mylonitic faults such as Cameron's Line are not unique single surfaces of dislocation but rather zones of imbricated lithologies (termed mélange) bearing mylonitic fabrics. Here, we see commingled gray-weathering quartzite- and granofels-bearing schist of the Hartland (OCh) and rusty-weathering schist and gneiss of the Manhattan (OZm) formations in fault rocks bearing a highly penetrative S1 + S2 mylonitic foliation. Lithologies typical of unit OZm are mostly found near the north end of the exposure. Although variable because of F3 folding, at the south end of the exposure, the S1 + S2 mylonitic foliation strikes N68°E and dips 22°SE and can be traced parallel to the axial surfaces of F2 folds of the S1 foliation in quartzites. The F2 folds are reclined and plunge 25° into S10°W. Elsewhere, the enveloping S2 mylonitic foliation is oriented N46°W, 27°SW.
At the north end of the large exposure, where rusty-weathering OZm predominates, OCh granofels layers, 30 to 50 cm thick, can be seen "floating" in a schistose matrix (Figure 23). Such intermixing is perhaps the product of shearing and imbrication related to the formation of mélange within the Cameron's Line thrust zone. Here the S2 foliation swings to N75°W, 35°SW. The folds and fabrics related to the F2 and older folds are strongly reoriented by F3 folds. Tight- to isoclinal F3 folds plunge 25° into S15°W with axial surfaces oriented N28°E, 68°SE. Beautiful examples of F2 x F3 interference patterns are found in this exposure.
Glacial plucking has here been facilitated by joints oriented N85°E, 70°NW. A broad roche-moutonnée structure oriented N10°E occurs at the north end of the exposure and glacial grooves and troughs are found elsewhere oriented N32°W but crosscutting relationships were not observed. Based on what we saw at Stop 4, we suspect that the NW-trending grooves are younger than the roche-moutonnée structure.

STOP 6. Typical Hartland Formation away from the Cameron's Line thrust zone.
At USGS bench mark S of The Pond
OHM 2020: Picked location from topo sheet overlay - not UTM coords.
Rocks of the Hartland formation here consist of typical gray-weathering, highly muscovitic schist and massive, structureless granofels in an exposure at the SE corner of "The Pond", across from the Plaza Hotel. The granofels layers are quite numerous; their thickness varies from 3 cm to 50 cm and they are separated by schistose layers, 3 cm to 4 cm thick, exceedingly rich in muscovite (only about 5% biotite). Bedding is thus preserved and our interpretation is that the protoliths of the granofels layers were turbidites. With a little imagination, relict grading indicates that bedding tops toward the NW with S0 and parallel S2 and S3 oriented N48°E, 70° to 80°NW.
Upright F3 synformal folds of S0 and S2 plunge 20° into S45°W with axial surfaces oriented N45°E, 85°SE. A marked difference in mechanical behavior is indicated as the granofels layers show only large-scale warping at the hands of F3 folds yet the schistose interlayers are strongly folded and crenulated. Glacial grooves are oriented N32°W indicating SE-directed glacial-ice flow.

STOP 7. Folded and glacially polished Hartland formation.
W of the Pond, opposite the Avenue of the Americas access to Park
Muscovite schist and interlayered granofels of the Hartland are cut by open warps of the composite S2 + S3 foliation. These folds, which must postdate the F3 folds, plunge southward at 51° with NE-trending axial surfaces. A minor shear zone in the center of the exposure cuts through a 10-cm-thick layer of amphibolite and an F2 reclined fold refolded by F3 occurs on the south end of the exposure.

STOP 8. Hartland rocks sheared along F3 limbs and glacial features.
On S side of West Drive, near SW boundary of Park
The effects of shearing along the limbs of F3 folds here produce a penetrative foliation oriented N32°E, 90° in highly muscovitic rocks of the Hartland formation. The effects of rounding and smoothing of the bedrock surface here are quite obvious as are glacial grooves oriented N38°W.

STOP 9. Hartland rocks exhibiting bedding.
On N side of West Drive near bridge over walkway from 7th Avenue
Pronounced interlayering of granofels and muscovite schist here typify the Hartland formation. Bedding (S0) and the S2 foliation are oriented N43°W, 30°SW near the vicinity of an F3 antiformal hinge area (7th Avenue Antiform of Figures 16 and 18). The F2 folds here show z-fold symmetry indicating we are on the eastern side of the south-plunging antiform.

STOP 10. Hartland rocks "safe at home" (Umpire Rock) .
Umpire Rock is the most-spectacular natural exposure in the southern part of Central Park. Here, rocks of the Hartland formation show the superposed effects of F2 and F3 folds, abundant syn- and post-tectonic pegmatite intrusives, brittle faults, and numerous glacial features. The rocks consist of interlayered muscovite schist and granofels that have been cut by numerous granitoids. F2 fold hinges are locally preserved but the glacial smoothing of the outcrop surface inhibits direct measurement of plunge orientation. The S2 axial-planar foliation is strongly folded here but displays an average enveloping surface of N77°W, 21°SW.
F3 z-folds vary from open- to tight- to isoclinal in profile and plunge 22° into S25°W with axial surfaces oriented N35°E, 72°SE. Beautiful interference patterns result from the superposition of F2 and F3 folds. Late-stage open warps with southward plunges are locally developed. Some pegmatites are syntectonic (foliated) and were intruded parallel to S2. Other granitoids are thin aplites oriented N50°E and crosscut all structural fabrics. Yet younger micaceous pegmatites cut the aplites. At least two brittle faults oriented N32°E cut the exposure; the one on the eastern edge of the outcrop shows a crumbly gouge zone roughly 3 m thick.
Perhaps the most-obvious geologic features here are of glacial origin. At the NW edge of the exposure, glacial meltwaters have modified spectacular glacial troughs oriented N28°W. These troughs are related to the overall SE-directed roche-moutonnée shape of the exposure with its steep drop off toward the playground area. A potpourri of glacial erratics can be found on this outcrop. We identified erratics of Palisades diabase and hornfelsic Lockatong Formation from the Newark basin W of the Hudson River, granite, and diorite.
Around the steep, north-facing wall of the exposure, note the glacial grooves oriented N46°W and the grooves oriented N35°W on the eroded outcrops immediately north of the north-facing wall. Of additional structural interest, the north-facing wall offers a rare glimpse at the shallow dip of the S2 foliation and a sub-parallel granitoid sill, all folded by F3? or younger open warps.

STOP 11. Pegmatite erratic on glacially polished Hartland rocks.
E side of walk E of Heckshcer Playground
The most-obvious feature of this stop is the 2m-high K-feldspar megacrystic pegmatite erratic but we can not be sure whether the erratic has been placed there during park construction or renovation. The “erratic” rests on rocks of the Hartland that have been scored by N38°W glacial grooves. F3 s-folds are locally found in the exposure.

STOP 12. Mylonitic Hartland rocks.
E of junction of walks N of Stop 11
The Hartland formation here shows some evidence for lithologic mixing; rocks of the Manhattan formation are present in the form of tectonic inclusions consisting of wisps- and shreds of aluminosilicate-bearing, rusty- to maroon-weathering schist. The outlines of the wisps and shreds are masked by shearing along S2 and S3. S2 is well developed here and is oriented N68°W, 42°SW. F3 folds are not hard to spot with their typical southward plunges and steep NE-trending axial surfaces.

STOP 13. The Manhattan formation, by the Carousel
The exposure of rocks immediately west of The Carousel show the rusty- to maroon-weathering typical of the Manhattan Formation (OZm). Layers and lenses of kyanite+quartz+magnetite weather in positive relief and outline the S2 foliation which is largely mylonitic. Here, S2 is variable but oriented N70°E, 25°SE because of pervasive F3 folds plunging 34° into S25°W. The F3 axial surfaces trend N42°E, 68°SE. We map this area as the beginning of the Cameron's Line thrust zone and links these exposures to those found at our earlier Stop 5.

A6: NEW INSIGHTS ON RIFT BASIN DEVELOPMENT AND THE GEOLOGICAL CARBON CYCLE, MASS EXTINCTION, AND CARBON SEQUESTRATION FROM OUTCROPS, AND NEW CORE, DRILL HOLES AND SEISMIC LINES FROM THE NORTHERN NEWARK BASIN (NY AND NJ)
Paul E. Olsen, Sean T. Kinney, Natalia V. Zakharova
Lamont-Doherty Earth Observatory of Columbia University
Palisades, NY 10968
Roy W. Schlische, Martha O. Withjack
Department of Earth and Planetary Sciences
Rutgers University
Piscataway, NJ 08854
Dennis v. Kent
and
David S. Goldberg
Brian E. Slater
New York State Museum
Albany, NY 12230
The Carbon Cycle, Global Environments, and the Sedimentary Record It is a viable theory that in the big picture, much of Earth’s geological record of is, in one way or another, a reflection of changes in the carbon cycle, itself uniquely (as far as we know in THIS solar system) and profoundly a reflection of life. Plausibly, because of the interplay between photosynthesis, weathering, CO2, radiative balance, and the thermal gradient of the crust and mantle, the Earth is the only body around our Sun with granite and plate tectonics (Sleep, 2012) and the only body with an atmosphere with significant O2 (Sleep, 2012). This field trip will view the Newark Basin (Fig. 1) and its sedimentary and biotic record though this lens of the carbon cycle. The fact that there is a Newark rift valley at all and that it is filled with largely red beds reflects this profound difference of our planet compared to our companions. Even the packaging of the Newark Basin sedimentary sequence, which is so profoundly cyclical and clearly paced by variations in the Earth’s orbit, seemingly entirely extrinsic to the intrinsic Earth system, must reflect a very strong, nonlinear amplification by feedbacks between the carbon cycle and climate. Finally, the end-Triassic mass extinction (ETE) appears to be an example of a carbon cycle perturbation caused by tectonics – the eruption of the giant Central Atlantic Magmatic Province (CAMP) pumping CO2 and SO2 into the atmosphere. These same rocks may be part of our effort to sequester anthropogenic CO2, itself a product of combustion of a half a billion years of photosynthetic natural carbon sequestration. The fact that the eruptions could occur at all may be a function of the same thermal gradient reflecting the radiative balance that makes our planet hospitable. Much of the theory of the Earth as it relates to life and the carbon cycle is on the fringe of knowledge, but it is useful to ponder how these things might work in order to frame testable hypotheses that may not only help us understand the Earth system from the seemingly arcane vantage of the Newark basin, but also frame hypotheses that have practical consequence for our future.

A6: NEW INSIGHTS ON RIFT BASIN DEVELOPMENT AND THE GEOLOGICAL CARBON CYCLE, MASS EXTINCTION, AND CARBON SEQUESTRATION FROM OUTCROPS, AND NEW CORE, DRILL HOLES AND SEISMIC LINES FROM THE NORTHERN NEWARK BASIN (NY AND NJ)
P.E.Olsen, S.T.Kinney, N.V.Zakharova, R.W.Schlische, M.O.Withjack, D.V.Kent, D.S.Goldberg, B.E.Slater

STOP 1-1. Cores, Seismic Lines and Posters at Lamont-Doherty Earth Observatory, Palisades, NY
Here we will examine cores, down-hole logs, seismic profiles, and some fossils from the New Jersey portion of the Newark Basin and in a more central position. These will relate directly to the outcrops will see after this stop.
Newark Basin Coring Project (NBCP) and Army Corps of Engineers (ACE) Cores
Stockton Formation - Princeton NBCP core and TW4: The facies of the Stockton Formation as seen in the Princeton core is closely comparable to the outcrops of the type area of the Stockton Formation near Stockton, New Jersey. Thick intervals of purplish, tan, and gray sandstone and minor conglomerate are interspersed with bioturbated red mudstone and muddy sandstone. Pedogenic features including cracks, slickensides, carbonate nodules, rhizoliths (root traces), and burrows are abundant.
Compare the red mudstone facies of the Stockton Formation in the Princeton Core with typical red mudstone from the nominal Stockton Formation of the TW4 core. Note that the huge sand-filled cracks seen in the TW4 mudstones are not seen in Princeton core mudstones. Also note the difference in color with the higher color saturation and slight purple tint of the TW4 mudstone. The TW4 facies resembles the nominal Stockton we will see in outcrop at Stop 1.2 (Fig. 24).
Lockatong Formation - Nursery and Princeton NBCP cores: Cores and logs: intervals of cores of exactly correlative lacustrine (Van Houten) cycles will be on display. Observe the decrease in thickness and change in facies from the Nursery core to Princeton, corresponding to the up-dip relationship between Nursery and Princeton and how that projects towards the hanging-wall side of the basin – the Granton Quarry area (Stops 1.3 and 1.5).
Also on display will be examples from these same cores of the lower Lockatong Formation, which changes dramatically in facies between Nursery and Princeton with correlation based on the magnetostratigraphy.
The trend from Nursery to Princeton is from thicker to thinner cycles, from finer to coarser grain, and a tendency for the lower Lockatong cycles to be replaced by red beds and tan and gray sandstone. This trend continues and is exaggerated from the Princeton area towards the northeast towards our field stops.
Passaic Formation – Somerset, Rutgers, and Titusville NBCP cores: Examples of stratigraphic overlap between the Rutgers and Titusville cores illustrates an extreme examples of lateral continuity. In particular are two siltstone layers only a few cm thick correlative between the two coring sites separated by 42 km. There is also a polarity transition just below these siltstones that serves as a corroboration of the hypothesis of correlation.
Examples of the single black-mudstone-bearing Van Houten cycle near the base of the Kilmer Member from the Somerset and Rutgers cores (11.5 km apart) will be on display. Note slight change in facies. As in the case above there is a polarity transition below and close to the base of this cycle and the base of the Member.
Passaic Formation and Orange Mountain Basalt – Martinsville core and ACE core PT-38: The upper few tens of meters of the Passaic Formation and its contact with the overlying Orange Mountain Basalt will be shown. The interval on display in the two cores contains the base of the Exeter Member of the Passaic Formation, the remarkably continuous and thin polarity zone E23r, and the projected level of the ETE. At first glance there is not much to suggest anything particularly momentous is going on here. However, correlation between the Jacksonwald Syncline section (Exeter) in the southwestern Newark Basin, from where most of the pre-ETE and ETE biological data come from, and the Martinsville, ACE cores, and exposures (Stop 1.7) is highly corroborated by cyclostratigraphy (the deep water phase of lacustrine cycle at base of the Exeter Member, polarity zone E23r, and the base of the Orange Mountain Basalt.
There is scant biological data from the cores themselves, no sporomorphs, for example; however, the spinocaudatan (clam shrimp) Shipingia olseni is present within the fine mudstones in E23r in the Martinsville core, consistent with its presence in the Jacksonwald Syncline section (Kozur and Weems, 2005). Supposedly, the presence of this taxon is indicative of a Norian age and is the principle basis for the argument that a major hiatus, spanning millions of years, is present between the base Exeter Member and what we identify as the ETE (Kozur and Weems, 2005; 2010; Tanner and Lucas, 2015).
The key observation supporting the hiatus as stated by Kozur and Weems (2011) is that, “…the upper Norian faunas were dominated by very large conchostracans, while the Rhaetian (and Hettangian) conchostracan faunas are everywhere composed of very small forms.” The lack of the early and middle Rhaetian clam shrimp zones and the presence of the large Shipingia just below the ETE in Newark Supergroup strata led to the hypothesis of this major hiatus. However, their hypothesis is falsified by the discovery of abundant large cf. S. olseni in late Rhaetian, largely marine strata in the North Germanic Basin underlain by strata contains the middle to late Rhaetian bivalve Rhaetavicula contorta and overlain by basal Liassic strata with psilocerid ammonites (Olsen and Kent, 2016).
Kent et al. (2016) note that, “…the recorded presence of the very short (∼10 ka) Chron E23r immediately below CAMP basalts in three entirely separate basins, namely Newark (Kent and Olsen, 1999; Kent et al., 1995; Olsen et al., 1996a), Fundy (Deenen et al., 2011) and Argana (Deenen et al., 2010), makes such a major regional hiatus untenable. This is because the hiatus would require essentially identical intervals of non-deposition and/or erosion in all of these basins, so that somehow deposition halted just after or else each section was eroded to variable depths exactly down to just above Chron E23r, the shortest identified chron in the Newark-Hartford APTS. But not to be deterred, (Tanner and Lucas, 2015) do not regard such an argument as precluding a regional unconformity and speculate that a late Rhaetian episode of uplift along the entire rift axis might somehow have caused such precisely timed non-deposition or erosion of the exposed strata in all of the rift valleys prior to the flood basalt eruptions.”
Examine the cores, and see if you can spot if there is any physical evidence for a hiatus.
In addition to the facies change seen across these three sites, from better cyclicity with dark gray shales in the deeper water units in the Jacksonwald syncline to the southwest, to obscure cyclicity in red beds in the northeast, there is also a parallel change from more or less consistent vertical patterns of cycles to a vertical pattern with fully fluvial conglomeritic facies below to a more marginal lacustrine facies above at the site of PT-38. The Jacksonwald area has been a major source of evidence on the initial ETE, including abundant Triassic-aspect crocodile-line tracks such as Brachychirotherium and Apatopus, while outcrops adjacent to the location of PT-38 have produced a post-initial-ETE assemblage of sparse sporomophs and macrofossil plants, and abundant footprints (Stop 1.7).
Preakness Basalt – ACE core PTI-3 and Lucent Technologies core MW-21D: ACE core PTI-3 was described by Tollo et al. (1990) and Tollo & Gottfried (1992). It contains both the pillowed lowest flow of the Preakness Basalt and the lower part of the second flow with the characteristic platy-prismatic jointing that we will see in exposures at Stops 1.8 and 2.5. Lucent Technologies core MW-21D was cored in New Providence, NJ adjacent to the Lucent Technologies (formerly Bell Labs) complex at Berkeley Heights, NJ at 40.688342°, -74.396989°. This core site is 1.7 km northeast from the site (40.676546°, -74.409439°) from which Blackburn et al. (2013) obtained a zircon U-Pb CA ID-TIMS, Thorium-corrected 238U-206Pb age of 201.274±0.032 Ma from a gabbroid float in a stream cut of Preakness Basalt. Several well-developed gabbroid layers are present in Core MW-21D and samples from this core produced an indistinguishable, although as yet unpublished, age (T. Blackburn and J. Ramezani, pers. com., 2014). There is a small gabbroid roadside exposure directly in-line and between these two sites at (40.677774°, -74.408121°) from which we have a sample that will be on display.
This Preakness date along with others from intrusions associated with the other basalt flow formations of the Newark Basin, tested and precisely corroborated the hypothesis that the cyclicity seen in the syn-CAMP lacustrine strata was astronomically paced. The durations of the sequences between basalt flow formation based on U-Pb dates provided by Blackburn et al. (2013) are indistinguishable from the astrochronological estimates derived from Olsen et al. (1996b) and Whiteside et al. (2007).
P.E.Olsen, S.T.Kinney, N.V.Zakharova, R.W.Schlische, M.O.Withjack, D.V.Kent, D.S.Goldberg, B.E.Slater

Passing TW4 core site at left
Passing TW4 core site at left at (41.002829°, -73.910658°)
P.E.Olsen, S.T.Kinney, N.V.Zakharova, R.W.Schlische, M.O.Withjack, D.V.Kent, D.S.Goldberg, B.E.Slater

PIP follows ridge crest of the Palisades cuesta
Palisades Interstate Parkway follows ridge crest of the Palisades cuesta at about 1/3 stratigraphic thickness of the sill.

Road follows a small fault with normal separation
This road follows a small fault with normal separation that offsets the Palisades ridge line, dropping down to the left.

STOP 1-2. Ross Dock Picnic Area. Fort Lee, NJ
Here we will examine strata below locally exposed Lockatong Formation that is intruded by the Palisades Sill. Then we will look at the olivine zone on the way back to the bus.
Walk south along the path next to the river to its termination at the south tip of the park. At several places we will look at mudstones and sandstones of the Stockton. Walk 960 yards south along the river path to beneath the George Washington Bridge. Continue 887 yards farther south looking for outcrops at head height on the right (west) of the path. Depending on the plant cover you will see variegated (tan purple and red) cross-bedded arkosic sandstones and minor conglomerate interbedded with massive, intensely red-purple mudstone. The mudstone is cut by numerous large and deep ptygmatic sandstone-filled cracks that are often vertically boudinaged. This is the same facies we see in TW4 below the possible Lockatong (Stop 1.1).

Phytosaur locality
At the end of the path along the Hudson is part of a set outcrops of some notoriety, having been the subject of page one of the 1910 Christmas Day pictorial section of the New York Times, entitled, “When the Giant Dinosaur Walked Down Broadway”. Never mind that it was not a giant, or a dinosaur, or on Broadway! It is in fact a partial disarticulated postcranial skeleton of a large phytosaur (semi-aquatic, non-archosaur, crocodile-mimic pseudosuchian) that was recovered at the water's edge (Fig. 25) on private land then owned by the “three Goetschius brothers” just south of the park boundary. It appears to have come from the transition between an overlying arkose and red mudstone. The specimen was discovered in March or April of 1910 by Jesse E. Hyde, Daniel D. Condit, and Albert C. Boyle Jr., who were at the time graduate students of Prof. James F. Kemp of Columbia University (Hyde, 1911). They contacted Barnum Brown and W. D. Matthew at the American Museum of Natural History (AMNH) in New York City. The specimen was collected by Brown for the AMNH over a two-week period in late December 1910, after a few months of negotiations with the land owners. The phytosaur locality has been misidentified in most published reports, and was cited by the New York Times (December 21, 1910) as being "a half-mile south of the George Washington Bridge, opposite 155th St.”, even though 155th St is closer to one mile south of the bridge! However Matthew (1911) and Hyde (1911) state that the specimen is from opposite 160th St., which is approximately 1/2 mile south of the bridge and there are outcrops still present on private land at (40.844472°, -73.965003°); The specimen is also commonly referred to as the "Fort Lee phytosaur", although it is actually from Edgewater. The specimen (AMNH 4991; Fig. 27) consists of several posterior dorsal, sacral, and anterior caudal vertebrae, both femora, tibiae, and fibulae, a few dorsal ribs, many gastralia, and numerous osteoderms. Huene (1913) described the specimen and named it Rutiodon manhattanensis. Based on the structure of the ilium, the generic assignment is correct (Huber and Lucas, 1993; Huber et al., 1993) but the specimen is indeterminate at the species level. This is the only vertebrate reported from this facies, but it suggests that further exploration might prove fruitful. AMNH 4991 is currently on exhibit in the Hall of Vertebrate Origins at the American Museum of Natural History in New York.
Take the switchback path that works its way up the hill to Henry Hudson Drive and proceed south toward the intersection with Main Street (Fort Lee) and the entrance to the park.

Weathered olivine zone of the Palisade Sill
Exposure on the north side of road has weathering profile of the olivine zone that can be clearly seen here. The olivine zone is weathered to a very crumbly diabase that, according to Naslund (1998), still has many fresh looking olivine crystals. The olivine zone is about 10 to 15 m above the base of the Palisades Sill and its weathering produces an obvious bench along the escarpment, essentially paralleling the lower contact of the sill, as observed by Walker (1969).
Proceed north along the base of the sill on Henry Hudson Drive, keep track of the bench and note where sedimentary strata at the base of the sill are exposed. Also note the faint and fine layering visible on the diabase surfaces near the base of the sill. Beware of vehicles!

Slightly discordant base of sill and metamorphosed Lockatong Formation
The thin-bedded to massive metamorphosed mudstones and siltstones, interbedded with tan arkosic sandstone, is typical of the lower Lockatong in this part of the basin, and it shows unequivocally that the red and tan units along the river are stratigraphically lower than Lockatong Formation. Of interest here is that as the sill cuts lower in the section, at either side of this outcrop, the strata become disrupted and the finer-grained appear to behave more competently while the coarser beds appear to have liquefied and partially and chaotically mixed with the diabase (Fig. 26). Note that the topographic bench tracking the olivine zone appears to bump upward here.
Proceed north under the George Washington Bridge. The road basically follows the base of the sill.

Razor-edged contact between sill and Lockatong Formation
Probably the best and most accessible contact between the Palisades Sill and underlying meta-sediments is here, where the contact tends to be planar, and very sharp, and although predominantly concordant, locally hops up or down in stratigraphy tens of centimeters. Note that over most of the exposure there is very little evidence of melting or assimilation and that fine-scale sedimentary structures are well-preserved despite proximity to the sill.
While these rocks are gray to nearly black, they contain no organic carbon. North along this same road, past the circle (at 40.862042°, -73.955783°), are exposures of similarly metamorphosed Lockatong Formation in a part of the stratigraphy (cycles W-5 and W-6 of the Nursery Member) that has been traced along the base of the sill to Hoboken and correlated with the NBCP cores (Olsen, 1980c; Olsen et al., 1989; 1996a). Away from the sill, the fossiliferous (clam shrimp, ostrcodes, fish, and rare reptiles), micro-laminated portions of the cycles have total organic carbon contents of 3 to 8 % (Manspeizer & Olsen, 1981), but here have essentially 0% organic carbon. Prior to larger scale metamorphism by the intrusions, the organic carbon content was probably in excess of 10%. This carbon, originally in the form of kerogen, was thermally cracked eventually to gas, finally methane and CO2, presumably with 13C-depleted isotopic ratios (δ13C of ∼-28‰). These greenhouse gasses made their way into the atmosphere, but whether they did so catastrophically, contributing to the ETE greenhouse crisis and “initial isotopic excursion”, or whether they leaked out slowly and assimilated without incident is unknown, although signs of disruption by escaping gas are certainly not obvious.

Reclaimed quarry in lower Palisades Sill at traffic circle
In this old quarry, the olivine zone is marked by a zone of deflected columns in the cliff face in fresh rock. Naslund (1998) notes flow banding is present within the olivine zone. You can project that zone of deflected column into the benchmarking the weathered olivine zone. What might the evidence be that the olivine zone represents a separate intrusive event or separate major pulse as suggested by Husch (1990), Puffer et al. (2009), and Block et al. (2015), and can you see any of the evidence here?

Several exposures of Lockatong and Stockton formations
There are several exposures of Lockatong and Stockton formations along the base of the Palisades Sill along this route, described in Olsen (1980c). Keep left to stay on River Road. On Gorge Road to the right are excellent exposures of Lockatong Formation described by Olsen (1980c, 2003) and Colbert & Olsen (2001). These allowed the section at Granton Quarry above the Palisade Sill (Stop 1-5) to be concatenated with that of the sections below the sill.

STOP 1-3. Churchill Road Exposure of Dramatically discordant sill and Lockatong, North Bergen, NJ
This is a very large, virtually unstudied exposure of a dramatically discordant contact between the Palisade Sill and the Lockatong Formation (Fig. 27). “Measured” using GoogleEarthTM (which has large uncertainties in altitude) the shear face of the wall is about 39 m. Using this as a guide, and accounting for parallax (non-quantitatively), about 23.5 m of Lockatong is exposed and the sill cuts down through it all towards the southeast. About three large cycles, each consisting of a couplet of a complex of prominent tan sandstone beds and complex of mudstone beds, are present averaging about 7.8 m thick.
Given that the average thickness of a 20 kyr cycle in this area is about 1.5 m (Olsen, 2001), consistent with smaller scale alternations of laminated and non-laminated mudstones at this outcrop, it would suggest the larger cycle is an expression of the short eccentricity (∼100 ka cycles). We will see more of this pattern at Granton Quarry at Stop 1.5.
Strata near the contact are deformed in a variety of ways. There are a number of blobby diabase intrusions that warp the surrounding strata, as well as several sheet-like ones that extend far from the main diabase body, and a series of small thrust faults (Fig. 27). This outcrop is very similar to that at Kings Bluff at Weehawken (Darton, 1890; Olsen, 1980c), except even more dramatic (Fig. 27). From here to the south near Weehaken, the base of the sill sits below the lowest well-developed mudstones on nominal Stockton Formation (Stop 1.4, below).

STOP 1-4. Palisades Sill contact with nominal Stockton Formation, North Bergen, NJ
OHM 2020: Coordinates are the same as for previous stop, so I ignored them. This is the Walgreen's parking lot.
This is another very large virtually unstudied exposure this time of largely concordant contact between the sill and underling Stockton Formation strata. “Measured” by GoogleEarthTM, the cliff face is about 51 m high (consistent with topographic map) (Fig. 28). Based on photographs and accounting for parallax (non-quantitatively) about 14 m of mostly tan and white arkosic sandstone and minor pebbly sandstone with a minor bed of olive-gray sandy mudstone are exposed here below the sill. Several tan arkosic xenoliths are present, one of which remains attached at its south end, making a flame-like structure (Fig. 28). This outcrop has been described by Zakharova et al. (2016) and this specific xenolith compared with the arkosic xenolith in core TW4 (Stop 2-1).
This facies of tan arkosic sandstone is common below and in part above, typical Lockatong Formation. To the north it seems to inter-finger with purple and red mudstones. While we are calling this Stockton Formation, it is unclear if it is a lateral facies equivalent of the lowest Lockatong or time equivalent to part of the Stockton as it is represented in the central Newark basin.

Driving down dip-slope of Palisade cuesta

STOP 1-5. Granton Quarry exposures of Lockatong Formation and Granton Sill, North Bergen, NJ
Leave vehicles and proceed to northeast corner of store. The following is adopted from Olsen (2003).
In the northeastern Newark basin, the outcrop belt of the Lockatong on both sides of the Palisades sill along the Hudson River is remarkably rich in vertebrate fossils, despite varying degrees of contact metamorphism. In this region, virtually all fine-grained facies and all cycles have some vertebrate body fossils. Here, only the Princeton, Nursery, and Ewing Creek members of the Lockatong Formation have been positively identified. The Granton Quarry is the most famous of all the fossil localities in this belt and, in fact, the entire Newark Basin.
Remnants of the old Granton Quarry are preserved between the new Lowes Home Building Center on the south and Tonnelle Plaza (Hartz Mountain Industries) on the north. Granton Quarry was actively quarried for road metal, fill and rip rap during the 1950s and 1960s and was abandoned by 1970, whereafter it was slowly consumed by commercial developments and warehouses. Nonetheless, excellent exposures remain. The site has produced, and continues to produce, extraordinarily abundant fossils, especially vertebrates, and it is certainly one of the richest sites in North America for the Triassic (Fig. 29). This is also the best locality on this trip to see the details of Lockatong-type Van Houten cycles. Eleven such cycles with a thin-bedded to laminated division 2 are exposed on the sill-capped hill: seven are exposed on the south-facing exposure (Fig. 30) where we will see them first (40.807058°, -74.017908°), three additional cycles are exposed on the east-facing exposure; and all 11 cycles are exposed on the north-facing exposure, which is where we will examine them in more detail (40.807380°, -74.017774°). The base of the section appears to be 38-46 m above the contact with the Palisades Sill (Van Houten, 1969). This contact may be close to what was, prior to intrusion, the local Stockton-Lockatong formational contact. This section has been described in several papers including Van Houten (1969), Olsen (1980c; 2003), Olsen et al. (1989), and Colbert and Olsen (2001).
According to Van Houten (1969), these Lockatong hornfels include calc-silicate varieties in the middle carbonate-rich part, and extensively feldspathized and recrystallized diopside-rich arkose in the upper part. Some beds of arkose show well-developed cross-bedding. Because of the buff arkose at the top of nearly every cycle, these are the most visually-graphic of the detrital cycles seen on this field trip. Here, the many correlated changes occurring though individual cycles can be easily seen (Fig. 30).
Cycles G3 and G7 (Fig. 30) have produced representatives of all the known skeletal remains of Lockatong vertebrates, except definitive examples of the holostean Semionotus. The basal portions of division 2 of both of these cycles have extremely high densities of fossil fish, especially the coelacanth Osteopleurus newarki (Schaeffer, 1952). Small reptiles are also surprisingly abundant, and many important fish and unique reptile skeletons have been discovered here by dedicated amateurs and donated to various museums through the years (Colbert, 1965; 1966; Colbert and Olsen, 2001; Olsen et al., 1989; Schaeffer, 1952; Schaeffer and Mangus, 1971). Without a doubt, the three most spectacular skeletons of small reptiles found in the Lockatong Formation come from this site. These include the type specimen of the bizarre "deep-tailed swimmer", Hypuronector limnaios (Colbert and Olsen, 2001), the peculiarly-abundant and sexually dimorphic, tanystropheid Tanytrachelos ahynis (Olsen, 1979), and the gliding lepidosauromorph Icarosaurus seifkeri (Colbert, 1966) (Fig. 29). Larger remains occur as well, of which the most spectacular is the skull of a juvenile rutiodontine phytosaur (Fig. 29), but isolated phytosaur bones and teeth are fairly common and isolated vertebrae of a metoposaur amphibian also been found. This biotic assemblage is very different than that seen in post-ETE strata, but some of the elements are present just before the ETE, including phytosaurs and tanystropheids, both based on footprints in the Newark – Apatopus and Gwynnedichnium, respectively.
Cycles G8 through G11 overlap with the section on the east side of the Palisades Sill as exposed at Stop 4, as has been previously noted. A prediction of this correlation is that cycle W0 should be equivalent to G11. Examination of the easternmost outcrops at Granton Quarry of cycle G11 show that this is indeed the case. In fact, this cycle is distinctive in having a very pyrite-rich division 2 that has strikingly bright yellow and orange clay seams on weathering, a feature not seen in other Granton Quarry cycles. With the sections from both sides of the Palisades Sill combined, it is now possible to look at trends in lithology and biota at the scale of from a few thousand years (within one Van Houten cycle) to over 1 million years (i.e. three McLaughlin cycles) (Fig. 31).
Van Houten cycles thin to an average of about 1.5 m in this region, and at least some cycles from the drier phases of the 404 ky McLaughlin cycles appear to be entirely missing or replaced by tan arkose, accounting for the disproportionally low (18m) thickness of McLaughlin cycles in this area. If they scaled to the Van Houten cycles that are easily recognized, the McLaughlin Cycle should be ∼20 x 1.5 m = 30 m thick. The couplets (i.e. varves) of micro-laminated mudstones are thinner than their counterparts towards the center of the basin, but not in proportion to the thickness of the cycles, again suggesting a preferential omission of drier facies in each cycle.
This is an extension of the same thickness and coarsening trend in the Lockatong Formation that we have seen going from the Titusville to Nursery to Princeton NBCP cores (Stop 1-1). It is consistent with thinning onto the hinge margin of a half graben growth structure and incompatible with the strict version of the Broad Terrane hypothesis. The “missing” cycles and corresponding thinning of the McLaughlin cycles is consistent with offlap and bypassing on the hinge margin during lake lowstands and is also inconsistent with the strict version of the Broad Terrane. In fact, projecting that trend to the east and north, one would expect the Lockatong Formation to thin further and disappear entirely into sandstones, becoming unrecognizable, which is exactly what it does.
The stratigraphic sequence in the Hackensack Meadowlands, underlying the Granton sill to the west of the sill’s dip slope, consists of arkosic tan sandstones, overlain by black shales (that surely represent much of the remainder of the Lockatong Formation), which are in turn overlain by red mudstones of the Passaic Formation (Parker, 1993). If something like the average accumulation rate, based on the thickness of the Princeton, Nursery, and Ewing Creek members in the vicinity of North Bergen and Edgewater (i.e. 18 m/McLaughlin cycle), was maintained upward to the position of the Graters Member of the Passaic Formation (encountered in a boring; Lovegreen, 1974 cited in Parker, 1993), there is sufficient stratigraphic thickness in this area for the rest of the Lockatong and basal Passaic Formation.
At the south-facing exposures, cycles G1 and G2 are injected by diabase of the 20 m thick Granton sill (Van Houten, 1969), another component of the CAMP, which has protected the Lockatong Formation from erosion in this area. Because this sill is thin, and the Palisade Sill fairly remote stratigraphically, much of the sedimentary rock is not as metamorphosed as under the sill; some cycles still have considerable organic matter, especially noticeable in cycle G3 which on the south side of the Quarry is black with significant organic matter (Maliconico, 2010), but has little or none at the north end, where we are looking. The change in bone color tracks the thermal maturity as well: black where relatively low and white where high. Perhaps, the sandstones interbedded with the formerly organic-rich mudstones could act as conduits in the up-dip direction, venting methane and CO2 into the atmosphere.

STOP 1-6. Passaic Formation and Copper Prospect at Lyndhurst, New Jersey
Leave vehicles and proceed to view the adjacent exposures. The following is modified from Olsen et al. (2004).
We have moved considerably up section from earlier stops as well as deeper towards the depositional center of the basin, although we are still in a marginal facies. These exposures reveal most of the Kilmer Member of the Passaic Formation (∼210 Ma, NBTS) ( Fig. 4) exposed on the east side of a prominent ridge marking the western border of the New Jersey Meadowlands. This ridge is characterized by a heterogeneous assemblage of red mudstones and sandstones. However, there are a few purple and gray units present, and the eastern and stratigraphically lowest of these is parsimoniously interpreted as marking the base of the Kilmer Member (Fig. 4).
The Passaic Formation, characterized by extremely widespread units with a particularly well-developed “layer cake”-style stratigraphy, marks a stage in the tectonic evolution of the Newark rifts. Based on the very slow rates of thickening towards the faulted margins of the basin (Stop 1.1; Withjack et al., 2013), extension rates were slowing, the basin was filling towards its outlet, and the basin floors were extraordinarily wide and flat. The red Passaic and other central Pangean equivalents are the strata that most people think of when they think Triassic. At yet a broader scale, the Passaic marks an interval where basins deeper within the arid belt and closer to the rifting axis began to receive considerable amounts of brine of marine origin with the consequent development of thick evaporite sequences (e.g. Osprey Salt of the Canadian Maritime margin).
Based on correlation to the central Newark Basin, albeit tentative, the exposures at this stop reveal the uppermost few meters of member T-U and the lower half of the Kilmer Member (Fig. 4). In the central Newark basin, the basal Kilmer Member includes a prominent Van Houten cycle with a well-developed black division 2. In the region around New Brunswick (NJ), this black shale and the underlying division 1 of this cycle are often rich in copper minerals, particularly chalcopyrite. At these outcrops in the northeastern Newark basin, the same Van Houten cycle apparently lacks black shale, instead having a purple shale with associated tan or white sandstones. The unit is still copper-mineralized, at least locally, and where intruded by thin diabase sills (2.2 mi) to the south-southeast in North Arlington (NJ), it was commercially exploited in what is supposed to be the oldest copper mine in North America – the Schuyler mine (Lewis, 1907). The exposures at this stop are almost certainly the prospect mentioned by Woodward (1944) on the Kingsland estate (located at - 40.8064893°, -74.1109759° inspired by the Schuyler mine but never worked extensively. An exploratory shaft at least was opened, and the now-cemented entrance is still visible. Tan and white sandstones associated with purple and gray mudstone are exposed and mineralized with the same minerals as at the Schuyler mine, including chalcocite (black copper sulfide), chrysocolla (bluish-green copper silicate), malachite (green copper carbonate), and azurite (blue copper carbonate). It is noteworthy that there is no evidence of diabase at this location because the presence of an intrusive diabase sill has been used as an explanation for the copper mineralization at the Schuyler mine (e.g., Woodward, 1944).
The overall section at this stop consists of lower red massive mudstones of member T-U, followed by the tan and white sandstones surrounding a purple well-bedded mudstone of the basal part of the Kilmer Member. This is succeeded by massive red mudstones, a well-bedded interval, and then red mudstones and fine sandstones with gypsum nodules. The overall stratigraphy is very similar to the expression of member TU and the Kilmer member in the NBCP cores we have seen at Stop 1-1.
A large collection of very well-preserved reptile footprints was made near here by Lawrence Blackbeer in the late 1960s (pers. comm., 1985; Olsen and Baird, 1986) (Fig. 32). Although the exact location was not recorded in detail, the lithology of the footprint slabs is consistent with the local expression of the Kilmer Member. This was confirmed by the discovery in 2002 of two well-preserved tracks during a field trip for IGCP 458 (Olsen, 2002) (by PEO and A.V. Hillebrandt, June 8, 2002) in appropriate lithology from between the two prominent copper-bearing sandstones at this spot (Fig. 32).
This Norian age assemblage is distinguished in the Newark Basin by the presence of relatively large grallatorid (theropod dinosaur) footprints, up to the size of Anchisauripus tuberosus; this is the oldest level in the basin with such tracks. Relatively large examples of the plausibly non-dinosaurian dinosauriform (silesaurid?) track, Atreipus milfordensis, are present, along with a the possibly dinosauriform or poposaurid track Evozoum sp. (“Coelurosaurichnus” sp. of Olsen and Flynn, 1989), as well as crocodile-line pseudosuchian track Brachychirotherium parvum, and the small lepidosaurian track Rhynchosauroides spp. This track assemblage records the beginning of the rise to ecological dominance of the dinosaurs, which in lower horizons are conspicuous by their relative rarity and small size. This assemblage is similar to that recovered from the Passaic Formation of Rockland County (see Stop 2-2).

STOP 1-7. ETE and E23r in uppermost Passaic Formation and Overlying Initial CAMP Basalt. Former Tilcon Quarry, Woodland Park, New Jersey 5
Leave vehicles and proceed to view the adjacent exposures. The following is modified from Olsen et al. (2004).
The “Four Seasons at Great Notch Spa and Club” (K. Hovnanian) “adult community” occupies the site of a quarry that produced a very large amount of important stratigraphic, sedimentological, and paleobiological information, especially during the last few years as construction proceeded for the development. The quarry was owned and run by a series of operators and is therefore known by various names, including: Little Ferry Asphalt, Union Building and Construction (UBC) Corporation, R.A. Hamilton, Dell Materials, and most recently Tilcon (the last operator). It has also been referred to as the “Clifton Quarry” and West Patterson Quarry (Gallahger & Hanczaryk, 2006).
The end Triassic extinction has left a rich, albeit asymmetrical, record in the northern Newark Basin. While most of the biological record below the ETE is from the southwestern Newark Basin, that above the initial ETE is from is northern part. Fortunately, the very short (∼10m, <20ka) interval of reverse magnetic polarity lies in close proximity under the ETE allowing correlation that is independent of biostratigraphy (although in agreement with it).
Two main localities have provided nearly all of the biotic data in the Northern Newark Basin, both of which are now-abandoned quarries incorporated into Montclair State University and the now-abandoned quarry (this stop). The Montclair State locality (40.868368°, -74.194389° and vicinity) produced a good collection of footprints in the 1970s into the early 1980s with some excellent examples being represented by actual specimens or latex molds ending up in the Princeton collection at Yale, Peabody Museum (New Haven, CT) or the Donald Baird mold collection, now with PEO (the latter badly in need of archiving). Overwhelmingly dominant are brontozoid tracks, including a full size range from Grallator to Eubrontes giganteus. Batrachopus cf. deweyii is the only other form recognized. The Woodland Park quarry site, described by Olsen at al. (2004) and Gallagher & Hanczaryk (2006), produced large numbers of a full size range brontozoid dinosaur tracks including Eubrontes giganteus, several with unique preservation styles, abundant Batrachopus deweyii tracks, and the lizard-like track, Rhynchosauroides sp. Possibly thousands of tracks from this site have been examined by amateur collectors, with many finding their way into museum collections, notably the Princeton collection at Yale, the New Jersey State Museum (Trenton, NJ), and the Morris Museum (Morristown, NJ). Despite the very large numbers of tracks this site has produced there have been no examples of any other footprint taxa, nor any typical Triassic forms, some of which have been found nearby in lower strata (e.g., Baird, 1986) in Essex County.
As it was in 2011, when Tilcon was winding down its activity, the quarry exposes about 50 m of uppermost Passaic Formation and most of the 55 m thick lowest of three major flows of the 150 m thick Orange Mountain Basalt (Figs. 33 and 34). In this area, the uppermost Passaic Formation consists of two units of strongly contrasting facies: a lower interval of fluvial facies, and an upper unit of marginal lacustrine facies. The bulk of the upper Passaic in this region consists of upward fining cycles of relatively poorly sorted pale red conglomerate and pebbly sandstone with poorly defined trough cross bedding grading upward into massive red mudstones and sandstones (described by Parker et al., 1988). The units are intensely bioturbated, which is what obscures the bedding. This facies is overlain by red and gray mudstones and sandstones with more distinct bedding and excellent preservation of small-scale sedimentary structures, which are more heterogeneous than underlying units. There are cross-laminated sandstones with channel morphologies, tilted thin beds that toe laterally into mudstones suggestive of small deltas or crevasse splays, tabular beds of climbing ripple cross-lamination, and thin bedded mudstone beds suggestive of suspension deposits in standing water. Many sandstone beds are bound by clay drapes, and many surfaces are covered by ripples, desiccation cracks, and trace fossils, notably reptile footprints. The uppermost surface of this interval is covered by the Orange Mountain basalt and locally seems to have preserved some depositional relief, including small channels (Fig. 33). Vertebrate footprint assemblages (Fig. 35) and floral remains from the upper facies completely lack all Triassic forms, indicating that the interval postdates the ETE.
The thin reverse polarity interval E23r was identified in the north Quarry wall at about 16 m below the Orange Mountain Basalt in the coarser, fluvial, conglomeritic facies (Fig. 34) that is similar to normal Passaic formation in this area (Parker et al., 1988).
The coring transect of the Army Corps of Engineers (ACE) Passaic River Diversionary Tunnel Project passed through this area, and a series of short cores (<200 m) were recovered through the uppermost Passaic and lower Orange Mountain Basalt (Fedosh and Smoot, 1988; Tollo & Gottfried, 1992; Olsen et al, 1996a; Olsen et al., 2002). All of them show the same facies transition as seen at this stop. Reverse polarity zone E23r has been identified in these cores at the appropriate levels as well (e.g., ACE core PT-38: Stop 1.1).
The floral assemblage from discontinuous pods of gray mudstone and sandstone at this stop include abundant remains of Brachyphyllum, a cheirolepidiaceous conifer and less common fragments of the dipteridaceous fern Clathropteris meniscoides, a large variety of casts of stems and rhizoliths and poorly preserved pollen mostly of the genus Classopollis. This is a typical post-ETE assemblage very similar to that in the overlying Feltville Formation. The fern Clathropteris meniscoides is the source of the spores at the spore spike in the southwestern part of the Newark basin.
A quite remarkable feature of the assemblage from this site is that it records the appearance of the first truly large theropod dinosaurs, and increase in size (length) of over 20% that occurs at or just after the extinction level. A 20% increase in track length should scale to a doubling of mass, and thus this represents a very significant change in the top predators. As spelled out by Olsen et al. (2002), there are two obvious possible scenarios to explain the abrupt increase in size in theropod dinosaurs across the Triassic-Jurassic boundary in eastern North America (and globally). First, that the appearance of the much larger theropods represents a dispersal event from some unknown location, or second, that it represents an evolutionary event. Thus far, we favor the second, evolutionary hypothesis for the appearance of large theropods and suggest that the abrupt increase in size is most easily explained by a sudden evolutionary response of the theropod survivors (which may have been quite small) to ecological release, operating at time scales of thousands of years. We hypothesize a response similar to that inferred for reptiles on modern islands lacking competitors. This evolutionary response hypothesis could be falsified by the discovery of equivalently large theropod bones or diagnostic Eubrontes giganteus (emphasis on the ichnospecies is important) tracks in unquestionably pre-ETE Triassic strata. Thus far these are wanting, contrary to assertions of, for example, Thulborn (2003), Lucas et al. (2006), and Lucas & Tanner (2008). In any case, this track assemblage suggests that the dramatic drop in non-dinosaurian diversity was caused by an extrinsic environmental catastrophe such as the CAMP, and the resulting drop in competitive pressure was the trigger for the global spread of large theropods. Sauropodomorph dinosaurs also survived the ETE, joining theropod and ornithischian dinosaurs to establish the familiar dinosaurian-dominated ecological pattern that dominated the terrestrial world for the next 135 million years.
The Orange Mountain basalt overlies the Passaic Formation and is a high-Ti quartz normative tholeiite (Puffer and Lechler, 1980; Tollo & Gottfried, 1992), a basalt type extremely widespread in the CAMP as the initial flow type. While it is the oldest flow sequence in the Newark Basin, slightly older flows (by thousands to tens of thousands of years), occur in Nova Scotia and Morocco (Blackburn et al., 2013). Based on the connection of the zircon-bearing Palisade intrusion to the Orange Mountain Basalt flows in Rockland County, the 238U-206Pb age of the basalt is 201.520±0.034 Ma and that of the ETE is 201.564±0.015 Ma based on the zircon ages and astrochronology (Blackburn et al., 2013).

Parking for stop 1-8

STOP 1-8. Upper Feltville Fm and lower Preakness Basalt Quarry
Leave vehicles at strip mall and walk about ∼145 yards (∼133 m) and enter woods down to creek). Proceed upstream ∼130 yards (∼ 119 m) observing outcrops of upper Feltville Formation to abandoned quarry in upper Feltville and basal Preakness Basalt. The following is modified from Olsen et al. (2003).
Manspeizer (1980) described this locality in that year’s NYGSA guidebook noting the three basic units present. The upper Feltville Formation, a lower pillowed flow of the Preakness Basalt and a second massive and highly fractured flow of the Preakness Basalt (Fig. 36). The Feltville Formation exposed in the old quarry and adjacent stream consists of interbedded tan and red sandstones and red and gray and purple siltstones. The latter contain sporomorphs, conifer fragments, and wood. In terms of the cyclostratigraphy of the Feltville, this sequence is the interval of maximum precessional variability in the 100 ka cycle exhibiting the lowest precessional variability within its 405 ka cycle. The second flow of the Preakness has a 238U-206Pb age of 201.274±0.032 Ma, which is in complete agreement with its cyclostratigraphic age (Blackburn et al., 2013).
The basal flow of the Preakness as exposed here consists of a pillowed basalt complex and more massive flow lobes that fed the pillows, all of which show considerable vesicularity. This is Preakness flow P-1 of Tollo & Gottfried (1992) and is a distinct and mappable unit extending at least from the ACE core transect to the north near the border fault. It seems to be absent from at least West Orange (I-280) to near Somerville, NJ, but reappears along I-287 at Pluckemin, NJ. Olsen (1980a; 1980b) described outcrops of the lower flow but did not differentiate it from the overlying flow P-2 of Tollo & Gottfried (1992). At this locality there is little metamorphic effect on the underlying Feltville Formation, which is to be expected because P1 was extruded into water, presumably as deep as the thickness of the pillowed flow itself. Proceed from the quarry up the hill on the north to West Overlook Avenue and then to the west to exposures of basalt. The contact between P-1 and Tollo & Gottfried’s (1992) flow P-2 can be seen here. P-2 is the very thick flow that is present all over the entire extent of the Preakness Basalt and is characterized by having an intense splintery or prismatic fracture (Faust, 1975) and gabbroid layers (Puffer & Volkert, 2001). Prévot & McWilliams (1989) noted that this flow has unusually low magnetic inclinations compared to the other Newark basin flows. They also found the same low inclinations in the second flow of the Hartford basin Holyoke Basalt and the Deerfield basin Deerfield Basalt. Hozik (1992) showed that the Sander Basalt shared the low inclinations unlike all the other basalts of the Culpeper basin. All of these low-inclination flows have the same chemistries (Puffer, 1992; 2003), all have gabbroid segregations, and all but the Deerfield Basalt have the characteristic splintery fracture. In the Hartford and Deerfield basins, a flow of similar chemistry but having a tendency to be pillowed is present below the flow with the low inclinations. As pointed out by Prévot & McWilliams (1989) these directions would seem to indicate correlation, and correlation within the time frame of secular variation, suggesting that these flows represent the same eruptive event of no more than 10s or 100s of years. The Sander flow with the low inclinations is over 200 m thick, and P-2 of the Preakness Basalt is more than 90 m thick, and if the flow extended from Massachusetts to Virginia, it would be one of the largest lava flows known on Earth.
In terms of environmental effects, rate as well as magnitude matters, and the eruption of this flow, if it was indeed one eruption, would have been among the largest flows known on Earth in terms of volume, and would have had significant global environmental effects. The largest single flow of the Columbia River Basalt is on the order of 5000 km3 (Tolan et al., 1989), but if the Preakness and its equivalents averaged 100 m in thickness, spanned 800 km along strike, and were 100 km wide prior to erosion, it would have a volume of 8000 km3. This does not include the area spanned by dikes of the same composition that extend well into Canada (McHone, 1996). Flow P-1 is highly vesicular at this locality and P-2 has very significant fracture porosity and permeability. The well-developed, platy-prismatic fracture in Flow P-2 is very well displayed here and could be very significant for sequestration. As previously discussed, Goldberg et al. (2009) argue that carbonation reaction in permeable zones of basalt could provide a significant locus for carbon sequestration. However, while there is a large amount of porosity and permeability obvious here, it has yet to be demonstrated that it exists at depth in these ancient basalts.

B1: THE GEOLOGY OF STATEN ISLAND - HARD ROCK GEOLOGY - SELECTED FIELD SITES
Alan I. Benimoff
Department of Engineering Science and Physics
College of Staten Island
Staten island, NY 10314
ABSTRACT
This field trip will visit two localities, namely the Staten Island serpentinite in the I-278 Road Cut and the Palisades Diabase at Graniteville Quarry Park in Staten Island, NY.
John McPhee(1993) wrote: “ Southeastern Staten Island is a piece of Europe glued onto an ophiolite from the northwest Iapetus floor”.
Staten Island NY, a borough of New York City, approximately 13 miles long axis by 7 miles short axis, has a very diverse geology (e.g., igneous Rocks, metamorphic rocks, sedimentary rocks, cross bedded sediments, glacial deposits, glacial striations and grooves, kettle holes, beach deposits, streams, bluebelts and coastal features). This field trip will focus on the Diabase of the Palisades Sill at the Graniteville Quarry Park in Staten Island, NY and the Staten Island Serpentinite.

B1: THE GEOLOGY OF STATEN ISLAND - HARD ROCK GEOLOGY - SELECTED FIELD SITES

STOP 1. Xenolith fusion (trondhjemite) at Graniteville Quarry Park , Staten Island, NY
At this stop we will examine a xenolith of argillaceous Lockatong Formation enclosed in Palisades diabase that has undergone partial fusion to yield a pyroxene trondhjemite. The sodium-rich slab-like xenolith of argillite is 30 m long, 0.5 m thick and strikes N 30° E with a vertical dip. The xenolith was derived from Lockatong located below the sill. One could think of this as ancient divergent plate boundary.

STOP 2: The Staten Island Serpentinite in the I - 278 Road Cut
Park on Melhorn Road. +40.608940°; -74.11433° we will meet here. We will then walk east on Lightner Avenue and take the dead end road on the right. Proceed on trail downhill and take the trail on the left, proceed uphill and proceed north to outcrop. This is a filled in road cut for a now de-mapped road. I-278 is to the north. Do not enter I-278!
This is an outcrop of Staten Island serpentinite that was emplaced during the Taconic Orogeny, during the assembly of Pangaea. The serpentinite was emplaced as an ophiolite along a plate suture between an island arc (Hartland Terrane) and sediments accumulating along the Laurentian continental margin(Manhattan schist). The serpentinite is composed of lizardite, chrysotile, antigorite and Olivine. chromite, magnetite, anthophyllite, magnesite and other accessory minerals. One could think of this as an ancient convergent plate boundary.

B2: NATURALLY OCCURRING FILTRATION SYSTEMS SEQUESTERING METAL CONTAMINANTS FROM HISTORICAL TAILING WASTES AT THE STERLING LAKE SMELTER COMPLEX, HUDSON HIGHLANDS, NEW YORK
Sivajini Gilchrist
School of Environmental and Sustainability Sciences
Kean University
Union, NJ 07083
Earth and Environmental Sciences
Newark, New Jersey 07102
Mining History
Over 15 million people in New York, New Jersey, Pennsylvania and Connecticut depend on the Highlands Region’s (Fig. 1a) 800,000 plus acres of forested watershed for drinking water (Porter, 2008). Large-scale iron mining operations from 1730 to the early 20th century (Smock, 1889; Ransom, 1966) exposed the Highlands to environmental degradation. Although the region is recovering naturally, tailing wastes are still visible and chemically reactive impacting soil and water quality. In addition to iron mining, the Highlands were also exploited for sulfide ores (Gilchrist et al., 2009) but volumetrically spoils from iron mining operations were far greater than sulfide mining operations, the Sterling Lake iron smelter complex is one such example. This area was denuded of its forest to support the smelting operations. Waterfront property owners extract the lake water for potable use. Despite visible tailing wastes chemically decaying in the vicinity, water pH was found to be neutral when measured during a study of this site (Gilchrist et al., 2011). How is this possible if heavy metals are abundant in these tailing wastes?
Soil cores and water samples were obtained from several locations at the site (Fig. 1b) and chemically analyzed to determine the extent of soil contamination. Geochemical results of the recovered soil cores were compared to regulatory standards and to background soils for the eastern USA (New York State Department of Environmental Conservation (NYSDEC) TAGM 4046, 2009) and the New Jersey Highlands soils (New Jersey Department of Environmental Protection & Energy (NJDEPE), 1993). Chemical analyses suggested that naturally occurring mechanisms are maintaining the neutral water pH. The Highlands Region is a desirable real estate for developers. It is hoped that obtaining answers to the natural recovery of an area impacted by past invasive destructive mining activities will fend off development to protect critical watersheds such as the Highlands region.
An active Panzhihua magnetite mining area in southwestern China yielded high concentrations of Ti, V, Cr, Mn, Zn, Cu, Pb and As in the area’s soils (Yanguo et al., 2003) due to airborne depositions from mining and smelting activities. Elevated levels of Cd, Cu, Pb and Zn were found in another but sulfur-rich magnetite mine in central China (Zabowski et al., 2001). These limited studies show that magnetite mining operations can deliver significant metal contaminants to surrounding soils.

B2: NATURALLY OCCURRING FILTRATION SYSTEMS SEQUESTERING METAL CONTAMINANTS FROM HISTORICAL TAILING WASTES AT THE STERLING LAKE SMELTER COMPLEX, HUDSON HIGHLANDS, NEW YORK

STOP 1. Lautenberg Visitor Center
All 4 – 5 stops are short walking distances around the mining complex, including the visitors’ center, which showcases a model of the underground mines and aboveground facilities before the whole operation was abandoned in the early 20th C. The exhibits also include samples of the rock types mined and other mining paraphernalia.
Against all odds, the once extensively mined area recovered with the return of the forest, a clean lake and streams with neutral pH waters. This is undoubtedly due to the naturally occurring filtration/retention systems at the site, both by the SOM and the sesquioxides in the lower soil horizons. The study was able to trace the Cr sources from the slag/ash to breakdown of the parent rock bearing magnetite and other Cr-bearing minerals. Whether these types of Cr filtration/retention systems can efficiently remove Cr in areas severely impacted by Cr contamination requires further study.

B3: LATE PROTEROZOIC SHEAR ZONES OF THE WESTERN HUDSON AND NEW JERSEY HIGHLANDS
Michael J. Kalczynski
Department of Earth & Environmental Sciences
Newark, NJ 07102
ABSTRACT
Multiple phases of deformation associated with the Grenville orogeny are recorded in the rocks exposed in the northern Reading Prong of southeastern New York and northern New Jersey. The rocks of the Hudson and New Jersey Highlands are considered to have formed in an island arc or marine magmatic arc setting ca. ∼1.3 Ga, as volcanics, volcaniclastics, and sedimentary rocks. Deposition terminated when continental collision resulted in the formation of a major mountain belt during the onset of the Grenville orogeny. Granulite facies metamorphism created the dominantly gneissic regional foliation and migmatization, with extensive pegmatite intrusion. During this time, the Ramapo and Reservoir faults were established as zones of major crustal weakness. Dioritic dike and stock intrusions occur shortly afterwards, but prior to the second event. The second Grenville deformational event was likely due to tectonic escape and resulted in the reactivation and creation of multiple dextral shear zones late in the Proterozoic.
The northeast-trending Ramapo and Reservoir fault zones were initially established during the earliest phase of the Grenville orogeny as ductile reverse faults. In the later phase, both zones were reestablished as ductile strike-slip faults. The shear sense is unequivocally dextral, evidenced by the multiple kinematic indicators such as S-C fabrics, rotated porphyroclasts, and asymmetric boudins. Evidence is also present for multiple subsequent reactivations, including later ductile and brittle fabrics.
Late in the Grenville cycle, a ∼35 km wide zone of anastomosing near vertical mylonite zones overprinted early shallowly dipping foliations. Locally, shear zones in the western Hudson Highlands became dilational and extensive alteration and vein mineralization occurred. The veins formed in dilational right step-over jogs during the late stages of movement in northeast trending dextral shear zones. Locally buffered fluids controlled mineralization, resulting in calc-silicate, ferromagnesian, and quartz-sulfide assemblages. This process produced three zones: 1) a ‘bleached’ zone of altered wall rock adjacent to the vein, 2) an outer ‘layered’ zone in the vein, of ferromagnesian-rich bands, and 3) a core of massive magnetite ore and secondary minerals.

B3: LATE PROTEROZOIC SHEAR ZONES OF THE WESTERN HUDSON AND NEW JERSEY HIGHLANDS

STOP 1. Unsheared Metavolcanic Gneiss, Harriman State Park, NY
Strongly inter-layered intermediate and mafic gneisses with migmatitic bodies, just outside of the SE shear zone. Mafic layers are characterized by assemblages of clinopyroxene and amphibole with minor plagioclase, magnetite, sphene, and apatite. Intermediate layers are mainly plagioclase with minor quartz, apatite, amphibole, and biotite. The felsic leucosome is composed of coarse plagioclase, quartz, and K-feldspar, which form veins and clots including classic “net veining”. Minerals exhibit preferred orientations in the gneiss and appear granular in the leucosome. Late stage K-feldspar pegmatites can also be observed in this outcrop, containing mafic gneiss xenoliths.
Gneisses exhibit a strongly banded, intermediately dipping, foliation that strikes N-NE. Isoclinal intrafolial folds can also be observed, with axis following similar orientation. This deformation is indicative of main stage Grenville tectonism, and was unaffected during the later tectonic event, associated with the formation of the ore deposits. Contrast these rocks with Stop 2.

STOP 2. Southeastern Shear Zone Boundary, Harriman State Park, NY
OHM 2020: Coordinates given in Guidebook are not correct.
Several meter scale lozenge and cigar shaped boudins of mafic gneiss are contained within mylonitic quartzofeldspathic gneiss, with folded biotite and local amphibole-rich layers. The layers appear contorted and wrap around the mafic bodies. The encased mafic gneiss is similar to that of Stop 1, however it also contains contorted folds and veins of magnetite. The long axis of the bodies and fold axis appear sub-parallel, and shallowly plunge to the northeast.
Both Stops 1 and 2 are similar in composition and therefore grouped within the same metavolcanic sequence. Long axis and fold axes roughly parallel shear zone boundaries and fabrics within. This location is at the edge of the southeastern dextral, strike-slip shear zone. Deformation steadily increases to the northwest, into the central shear zone, characterized by a steepening of planar fabric and increase in intensity of linear fabric. The contrast of the features at Stop 1 with Stop 2 shows the difference between the first main Grenville and second strike-slip events.

STOP 3. Hogencamp Mine, Harriman State Park, NY
Hogencamp Mine lies in the southern part of the mineralized zone. Here the sheared wall rock is dominated by quartzofeldspathic and amphibole-pyroxene (metavolcanic) gneisses with inter-layered calc-silicate gneiss and marble locally. Hogencamp Mine was active from the earliest to latest 18th century. It is characterized by a series of meter to several meter scale horizontal and vertical mine shafts and open pit mines. The mines can be traced along strike for up to a kilometer. The mineralized zone that hosts Hogencamp Mine is roughly 6 kilometers long and extends into Pine Swamp Mine (Stop 4). The vein ranges in thickness from 3 to 15 meters at the mine locations to as little as one meter in the narrow zones connecting the deposits. The Hogencamp Mines can be followed to the southwest from this location for up to a kilometer.
The vein-wall rock contact is sharp and semi-concordant to mylonitic foliation. On the small-scale it appears slightly discordant, crosses foliation and erodes into the wall rock. This is best observed in the open pit mine, directly in front of the northeastern most mine shaft, below Cape Horn (Fig. 10). Here, the bleached zone is characterized by the deposition of calcite and scapolite, and retrogression pyroxene to amphibole, also containing phlogopite, calcite, and minor apatite locally. Earliest vein deposit is characterized by layered amphibole, orthopyroxene, and clinopyroxene, later by massive clinopyroxene and magnetite, cemented by late stage, interstitial calcite in the ore zone. Clinopyroxene and localized magnetite are euhedral, forming doubly terminated crystals, thought to have crystallized in cavities. The veins are also intruded by very coarse grained pegmatites which contain xenoliths of the mafic vein material.

STOP 4. Pine Swamp Mine, Harriman State Park, NY
Pine Swamp Mine lies in the northern part of the shear zone within the same mineralized vein which hosts Hogencamp Mine, roughly one kilometer alone strike (NE). Pine Swamp is also characterized by a 3 to 12 meter horizontal mine openings and several, meter scale open pit mines (Fig. 10). The mines that compromise the Pine Swamp deposit can be traced along strike for several hundred meters, with minor semi-concordant offshoots in the northern extent of the deposit. This portion of the hydrothermal vein lies dominantly within sulfide-bearing quartzofeldspathic gneiss country rock, which contains inter-layered metavolcanic gneisses. The bleached zone is primarily defined by retrogression of pyroxene to amphibole, also containing minor amounts of scapolite, and apatite locally. Orthopyroxene and amphibole dominate the narrow layered vein and thick massive sequences followed by the magnetite deposits. Massive minerals are locally cemented by late stage sulfide minerals, mainly pyrite and pyrrhotite. The flat wall adjacent to the mine proper is yellow to rust colored, due to the weathering of the sulfide-rich country rock. Massive minerals orthopyroxene, amphibole, and substantial magnetite can also be observed.

STOP 5. Lake Tiorati Diorite, Harriman State Park, NY
Pluton of coarse- to very coarse grained black and white speckled diorite. On the south side of the outcrop, the diorite is equigranular in texture with random grain orientation. It contains a roof pendant of well-foliated biotite quartzofeldspathic gneiss that exhibits crenulation cleavage. The xenolith contains a drag fold along its contact with the diorite. It also contains a rim of granitic pegmatite that connects to pegmatite and quartz veins within the diorite. The diorite contains plagioclase and hornblende and clinopyroxene but with brown cores or orthopyroxene. Other phases include magnetite and ilmenite. In the northern part of the exposure, the diorite is crossed by anastomosing mylonite bands. The mylonite strikes northeast and is near vertical. Lineations plunge shallowly to the northeast. Kinematic indicators include rotated porphyroclasts and S-C fabric. Where it can be determined, shear sense is consistently dextral.
Subsequent to the first tectonic event which included the nappe emplacement and granulite facies metamorphism, there was a period of intermediate plutonism. The xenolith was deformed and metamorphosed prior to intrusion. The xenolith became more ductile as a result of the heat of the pluton. Thus, drag folds formed along its edges as it fell into the magma. The magma was hot enough to cause partial melting of the rim of the xenolith, producing a granitic melt. The diorite crystallized at a higher temperature than the granitic melt. Fractures opened in the newly crystallized rock and the remaining granitic melt squeezed into them forming the veins. Later deformation produced the mylonitic fabric in the diorite. This outcrop is at the eastern edge of a large dextral strike-slip shear zone with similar orientation.

STOP 6. 17A Indian Hill Mylonite Zone, Tuxedo, NY
The rock is biotite quartzofeldspathic mylonite gneiss with interlayers of biotite gneiss locally, interpreted to have a volcaniclastic origin. The mylonite is well foliated and lineated and composed of plagioclase, quartz, potassium feldspar, and biotite. This mylonite exhibits well developed kinematic indicators including S-C fabric, reverse shear cleavage (RSC), rotated porphyroclasts, and shear bands. These kinematic indicators show a consistent dextral shear sense. The width of the zone and the low S-C angle indicate significant offset during the second event. Because this shear zone developed in biotite-rich gneiss, it displays kinematic indicators better than most zones. It is another in the series of anastomosing dextral shear zones that were produced during the second event. The gneiss is interpreted to have a volcaniclastic origin.

STOP 7. Ramapo Fault Zone, Riverdale, NJ
The northeast-trending Ramapo fault zone is the major border fault which juxtaposes the Proterozoic gneisses of the New Jersey Highlands with the Mesozoic sedimentary and igneous rocks of the Newark Basin. Width of the fault zone varies from approximately 5 to 10 km (Ratcliffe, 1980). Abundant moderate to steep southeast-dipping zones up to 25 m thick are developed within the granitic gneisses of the fault zone and exhibit mesoscopic S-C mylonite fabric. The fault zone is also intruded by mafic dikes which have been subsequently sheared during brittle reactivation. The Ramapo fault zone originally developed as a reverse right-lateral strike-slip fault during the Grenville orogeny (Ratcliffe, 1980) and has a long and complex kinematic history which included four to five recognizable episodes of fault movement. Despite the long history of reactivation of the zone there is no strong evidence of any post-Mesozoic or neotectonic movement. The mylonites within the Ramapo fault zone consistently indicate top to the northwest reverse faulting. These zones were reactivated under mid- to upper-greenschist facies conditions during the Taconic orogeny approximately 450 to 460 Ma (Ratcliffe, 1980) (Costa and Gates, 1993).
This exposure is located in Foot Hill Park at the end of West Parkway in Riverdale, New Jersey (Fig. 11). The entire exposure consists of ultramylonite of the Ramapo fault zone. Glacial striations oriented essentially north-south have polished the surface of the exposure. The alternating black and white/gray bands of foliation dip moderately to the southeast. The black bands are composed of fine-grained foliated chlorite, whereas the white/gray bands are quartzofeldspathic. Both quartz and feldspar deformed in a ductile manner, and are extensively dynamically recrystallized. Small grains of pyrite are present within the foliation.

STOP 8: Reservoir Fault Zone, West Milford, NJ
This stop illustrates how hydrothermal chemical and resulting mineralogical changes in a fault zone can change deformation style from brittle to ductile. We will observe undeformed protolith (granitic gneiss), hydrothermally mineralized cataclasite (brittle), and mylonite (ductile) of the mineralized zone. The undeformed to slightly deformed rock is mapped as pyroxene gneiss and interpreted as a metasedimentary sequence. The rock consists of diopside-, amphibole- and rarely scapolite-bearing granitic to quartz dioritic gneiss with sparse inter-layered amphibolite gneiss and pegmatite veins. The faulted rocks are cataclasite and breccia with mainly rounded blocks and clasts of granitic-quartz dioritic gneiss.
The matrix material is composed of ∼95% randomly oriented actinolite with minor epidote, albite, chlorite, and sulfides although finely ground xenocrystic phases from the gneiss are locally abundant. Thin ductile shear zones can be found in this outcrop but the structures observed are primarily the result of brittle deformation coupled with hydrothermal activity that produced the amphibole-sulfide mineralization. After formation through hydrothermal alteration, the amphibole-rich matrix underwent ductile deformation forming an S-C mylonite, more typical of rocks found in the center of the fault zone. The ductile deformation produced a strong foliation with significantly reduced grain size. Kinematic indicators include dragged foliation, S and C bands, rotated porphyroclasts, and offset markers showing a consistent dextral strike-slip sense (Gates, 1993).

B4: LOWER TO MIDDLE DEVONIAN ROCKS OF THE DELAWARE WATER GAP NATIONAL RECREATION AREA, NEW JERSEY: FRACTURE AND LITHOLOGIC CONTROL ON ROCK-SHELTERS, KARST AND GROUNDWATER FLOW
Don Monteverde
Ron Witte
Steve Domber
New Jersey Geological and Water Survey
Trenton, 08624
Kittatinny Mountain is a major ridge that crosses eastern Pennsylvania, through northwestern New Jersey and into southern New York. It is underlain by Middle Silurian Shawangunk Formation, a resistant quartz sandstone to quartz-pebble conglomerate that separates younger Silurian and Devonian carbonate and clastic sediments on the west from Cambrian and Ordovician flysch and platform carbonates to the east. Kittatinny Mountain displays a change in structural trend from northeastward to northward near an exposure of Upper Ordovician nepheline syenite, part of the Beemerville Intrusive Complex. Westward this same structural trend is marked by upright and northwest directed overturned folds and well developed cleavage in Pennsylvania, which becomes a broad zone of gently dipping formations generally devoid of a penetrative cleavage in New Jersey. Here outcrop widths of the units are doubled. Tight and overturned folding with cleavage development and an associated decrease in outcrop width reappears farther to the north across the New York border. This undeformed zone widens to the west creating bowed margins on maps and DEMs with the syenite body at the center of the bow.
Did the Beemerville Intrusive Complex form a rigid block that created a strain shadow against Alleghenian westward directed compressional deformation? Preliminary field data in conjunction with regional gravity and seismic reflection studies while not definitively pointing to this hypothesis as the only possible conclusion it also does not negate it as a possible answer. Other possible explanations exist including indentor-controlled variability and margin-controlled geometry for example which require further research. At this point we favor an interaction with a foreland obstacle, the Beemerville Intrusive Complex.
The strain shadow creates an impact on weathering and groundwater flow as compared to the more highly deformed regions to the north and south. Karst development has to date only been found within the strain shadow, mainly in the Onondaga Limestone where beds dip uniformly gently to the northwest. Here joints, enlarged by dissolution, dominantly control groundwater flow. Other reactions of weathering to this change in structural style along strike are investigated such as joint cave development in non-carbonate rocks.
The advent of DEM’s (digital elevation models) and LIDAR (acronym for Light Detection and Ranging) as well as Google Earth has allowed the investigation of the detailed landscape without leaving the office.
These tools are especially helpful with the geology of northwestern New Jersey. Using these tools, one sees a long curving ridge stand out in the topography that trends westerly out of eastern Pennsylvania, turning more northeasterly through New Jersey and more northerly into New York. Its name depends on its location, Blue Mountain in Pennsylvania, Kittatinny Mountain in New Jersey, and Shawangunk Mountains in New York (figure 1). It also forms a geological time break in that older rocks from Ordovician to Mesoproterozoic lie to the east and the younger rocks ranging from Silurian and younger to the west. One particular feature is an apparent nearly doubling of the outcrop width in New Jersey between Kittatinny Mountain and the Delaware River. Several different belts of rocks increase in width across the Culvers Gap, Branchville, Milford and Port Jervis South quadrangles (figure 1).
The best place to observe this morphologic change in the field is from High Point State Park in northwestern New Jersey. At the High Point monument (figure 1), beautiful vistas are open in all directions that offer a good vantage point to observe the changing topographic expression of the regional landscape. The visible topography is mostly controlled by the underlying bedrock with locally a blanket of thick glacial deposits. The ridge is the Middle Silurian Shawangunk Formation with the younger Bloomsburg Red Beds forming the western slope of Kittatinny Mountain. In a visual traverse beginning in the northwest, the distant ridges comprise the gently tilted Devonian and younger rocks of the Appalachian Plateau termed the Poconos in Pennsylvania and Catskills in New York. Northward is the termination of the Shawangunk Mountains/Formation. Eastward, there is a multilayered assemblage of rocks in both type and time. Just below the overlook the sandstone, greywackes and slates of the Ordovician Martinsburg Formation are visible. Farther afield are well-defined ridges in the Hudson and New Jersey Highlands consisting of Mesoproterozoic metamorphic rocks related to the Grenville Orogeny. A linear valley between the low lying Martinsburg ridges and the metamorphic ridges, named Kittatinny Valley in New Jersey, contains a belt of Cambrian and Ordovician carbonate rocks that lay in a recess position due to their higher degree of erosion. Southward, Kittatinny Mountain swings westward into Pennsylvania.
This field trip is not to investigate the reasons for this increased width of the exposed Middle Devonian through Middle Silurian rocks, though we will present two possible explanations. The field trip will offer examples of how the structural imprint, related to this increase of the outcrop belt, plays a role in many different features such as karst, groundwater flow, and habitation by early man.

B4: LOWER TO MIDDLE DEVONIAN ROCKS OF THE DELAWARE WATER GAP NATIONAL RECREATION AREA, NEW JERSEY: FRACTURE AND LITHOLOGIC CONTROL ON ROCK-SHELTERS, KARST AND GROUNDWATER FLOW

STOP 1a: Jager Road (near Brau Kettle), Sandyston Township, New Jersey
Location 1a-1 – Creek bed just downstream from culvert 1 (fig. 1-15) near Schoharie – Onondaga contact.
Features - Large solution joints, Onondaga Limestone (Edgecliff Member) and swallow hole along left bank.
Discussion – Here the Onondaga limestone forms the creek bed, which is primarily a bedding-plane dip slope cut by several large solution joints (fig. 1-16). The rock is a thin to medium-bedded, fine-grained, faintly nodular, non-cherty, sparsely fossiliferous limestone. Given its proximity to the Schoharie contact, the limestone probably belongs to the Edgecliff Member. Large crinoid columnals that are used to define Onondaga’s base have not been found near stop 1. However, the scarcity of outcrops due to dip slope geometry and burial by glacial cover in this area makes their discovery fortuitous at best. The main point to take away from this “blah, blah, blah” discussion is that the lower Onondaga in Karst Park is non- to sparsely-cherty and that is where many of the sinkholes occur.
Systematic joints in the Onondaga generally are aligned along two major trends (fig. 1-2). Enlargement of these joints and their intersections over time by dissolution, as well as minor bedding-plane dissolution has resulted in an extensive, integrated network of subsurface conduits (will discuss further at Stop 1b, Brau Kettle). The long axis of oval to trough-shaped sinks and lines of multiple sinks in Karst Park are aligned along these trends showing that karst features are strongly controlled by jointing (probably not an epiphany to most, but the lead geologist at this stop has a surficial geology background and is amused by simple observations). Solution along joints has resulted in various forms. In most places, joint surfaces are straight-walled to slightly curvilinear. Elsewhere, digitate forms (fig. 1-16) are observed, the result of dissolution along closely-spaced orthogonal to perpendicular joint sets. Also, in a few places, short, narrow openings occur that suggest a distinctive vertical component to dissolution.
A small swallow hole is found along near base of cascades, along the stream’s left bank below the roots of a small tree (fig 1-17). The swallow hole is following a large joint (020° trend), draining southwest. It is now partially covered in debris (mostly gravel). Scraps of screening and rebar (also found at other swallow holes) show manmade interference with natural flow conditions. These efforts generally fail, but once in a great while they’re thwarted by inquisitive geologists (ask Don). Most of the time this area was observed, about 70% of stream flow entered the swallow hole. Remaining flow continued downstream toward the left-hand bend eventually disappearing into the channels coarse alluvium. Over the last few years, flow many times has been observed to continue downstream past the bend to Stops 1a-2, 1a-3, and 1a-4 (fig. 1-15). The main reason for this is that the swallow hole at Stop1a-1 has become partially blocked with gravel and debris, material washed in during periods of storm-related discharge or maybe Don (the geologist not the rock) had something to do with it.
Head downstream to Stop 1a-2 either by following the stream bed (only if it’s dry) or by following the stream’s left bank. The small pit you pass on your right supplied sand to local denizens. The sand is eolian, blown off late Wisconsinan glacial outwash braid plains in nearby Minisink Valley. The sand is part of an extensive eolian sheet that has been found as much as 200 feet (61 m) above the valley floor. Just north up Stop 1-b, small sand dunes as much as 5 feet (2 m) high, cover the east side of the valley (a story for another time).
Location 1a-2 – Creek bed downstream from left hand bend.
Features - Buried swallow hole below slump, Onondaga joint-blocks, coarse gravel bar.
Discussion – Stream flow to location 1a-2 is rare. During a field trip to this area in February, 2016, the typical view of stream flow downstream from culvert 1 (the one where the stream disappears before the bend) was not so typical. Upon arriving at location 1a-2, two observations stood out: 1) most stream flow (∼ 75 %) was disappearing into an area of boulder alluvium beneath a small slump along the channel’s right side (fig. 1-18) and the remaining flow was diverted around a coarse gravel bar (located just upstream from the slump) to a small swallow hole located along the streams left bank at Stop 1a-3.
The sinking stream was probably draining into a large open joint that may have been open for observation at one time. However, recently slumped sediment (eolian sand overlying till) and Onondaga joint-blocks have covered the swallow hole. It appears that under natural conditions, variable discharge along reaches between swallow holes may be due to blockage of swallow holes upstream. Over time, the cyclical filling and emptying of swallow holes (collapse into sink holes or erosion by running water) has resulted in a complex stream flow history. Also, heavy precipitation may overwhelm the capacity of the swallow holes to drain the creek, and channel bars may also divert flow around or to swallow holes.
Onondaga joint blocks here are non-cherty and sparsely fossiliferous limestone similar to that at Stop 1a-1. Given the gentle dip of bedding (<15°), this limestone and outcrops downstream probably belong to the Edgecliff member.
Location 1a-3 – Creek bed just downstream from Stop1a-2.
Feature - Swallow hole along left bank in collapsed till.
Discussion – The swallow hole (fig. 1-19) is a small sinkhole formed mostly in till that underlies the left steam bank and hill-slope. Shallow bedrock in the stream channel just downstream from this location suggests that bedrock is very near the surface below the sink. It is very probable that this sink overlies a large solution joint or solution joint intersection. Again, it’s very rare for surface drainage to reach this location, but this year’s February storm was severe with runoff heightened by frozen ground and melting snow.
Location 1a-4 –stream channel just upstream from culvert 2.
Features – Small cave along right stream bank, joints, Onondaga Limestone
Discussion – The intersection of a large solution joint (114° ∼v) and creek channel (possibly JI) forms the opening to a small cave (fig. 1-20). The entrance is 28 inches (71 cm) wide and 32 inches (81 cm) high with the top of the entrance formed by soil and tree roots. Bedding is 021°10° NW, similar to bedding at Stop 1a-1. The large solution joint that forms the cave entrance trends 114 degrees and has nearly vertical to slightly scalloped sides (possibly eroded by sediment laden water). The 114° trend is part of a regional set of cross joints that cluster around 120 degrees. The cave floor from its entrance extends about 5 feet (2 m) before it drops another 3 feet (1 m) into a gravel choked opening. During periods of very high stream flow, the creek partly flows into the cave and over the years its floor near the entrance has filled with sand and fine gravel. As elsewhere, a small grate near the entrance does prevent most of the coarse sediment from entering the cave.
The Onondaga here is very fine grained, non-cherty, thin to medium bedded and slightly flaggy limestone. In places, silty (?) laminae with bedding parallel, curvilinear traces mark the rock’s weathered surface (fig. 1-20).
Location 1a-5 – stream channel downstream from culvert 2.
Features – Spring, small reservoir and box.
Discussion - Several small springs are located along south side of Jager Road. Here the small reservoir and box (fig. 1-21) are typical structures used to collect water where it is often directly piped down slope to another holding area. The springs and seeps found along the south side of Jager Road discharge at or very near the till/rock contact. The small stream-cut valley topographically cuts this contact and together with the northwest dip of bedding creates favorable conditions for the emergence of springs. Given the occurrence of open solution joints along the rock’s surface springs probably represent areas where water flow has been concentrated.
The new retaining wall was built after flood waters from then Tropical Storm Sandy (10/29/2012) washed out the road, nearly removing most of the eastbound lane.
Location 1a - 6 – just downstream from culvert 3.
Features – small swallow hole along right bank near right concrete abutment. Located at base of steep slope.
Discussion – Lastly, if we look downstream from culvert 3, you’ll notice a small opening (22” wide (56 cm) by 16” (41 cm) high) along the stream’s right bank just below the concrete abutment (fig. 1-22). Just past the opening the swallow hole’s floor drops 3 to 4 feet into a small trough that trends about 55 degrees. The trough walls are partially bounded by outcrop, suggesting that this opening is following a large solution joint. Similar to the cave at Stop 1a-4, soil and tree roots form a ceiling. The opening has increased in size four fold over the last two years. Presumably, decreased subsurface discharge upstream due to sediment infilling of swallow holes, has increased discharge in the creek’s lower reaches. These hydraulic modifications are episodic and may only take one or two good storms to greatly alter stream flow.
Below culvert 3 (fig. 1-15) most of the stream drains into the swallow hole directly or seeps through the gravelly alluvium adjacent to it. Downstream the creek is usually dry until input from a small spring below culvert 4. From here discharge seeps into boulder alluvium within 100 feet (30 m) of where the spring enters the channel. Normally the creek is dry downstream until it picks up outflow from Brau Kettle.

STOP 1b. Brau Kettle (spring and sinkhole)
Location – 125 feet south of Old Mine Road and Jager Road intersection.
Features – Brau Kettle (spring and sinkhole)
Brau Kettle is a unique sinkhole-spring located along the eastern edge of Minisink Valley near the intersection of Jager Road and Old Mine Road in Sandyston Township, New Jersey (fig. 1-2). References to the kettle go back to the early French and Dutch settlers. The name was likely derived from the Dutch word for “brewing” or “boiling” (Dalton, 1976), a fitting description of the spring during discharge.
The kettle (fig. 1-23) is a conically shaped depression approximately 10 feet (3 m) deep by 20 feet (6 m) wide with its floor located in till. The sloping walls of the kettle are in thin wind-blown sand and till. Depth to rock is unknown, but given the kettle’s geometry and discharge history, it is assumed that the Onondaga Limestone is very near the kettle’s floor. Brau Kettle can be classified as an intermittent spring that varies from dry, to partially filled, to spilling; with highly variable fill and spill periods. A hydrogeologic investigation of Brau Kettle and its relationship to the Onondaga Limestone commenced in 2008 by the New Jersey Geological and Water Survey under a research permit granted by the National Park Service. This investigation consisted of measured hourly water level data using an ADR logger from the kettle and a nearby domestic well, precipitation data, and kettle discharge measurements.
It is hypothesized that the kettle was formed when a near-surface solution feature (joint or joint intersection) in the Onondaga Limestone enlarged to the point where the overlying surficial materials collapsed creating a sinkhole. Over time the flowing groundwater removed most of the finer materials leaving a boulder lag on the kettle’s floor. Because the kettle is well above the Delaware River near the base of Wallpack ridge, groundwater only rises in the kettle during wet recharge periods. Farther downstream (closer to the Delaware River) is a series of perennial springs which discharge (in a boil-like fashion) through glacial outwash and postglacial alluvium. The lower elevation springs can be thought of as the perennial “base-line” discharge points and the kettle can be thought of as the overflow or relief valve when groundwater levels are elevated and discharge is high through the local joint-controlled hydrogeologic system.
Figure 1-24 shows selected water-level elevation data for the kettle and a nearby domestic well and precipitation data. The numbered descriptions below refer to the corresponding number on Figure 1-24. 1) Dashed grey line is elevation of base of kettle outlet channel; kettle elevations above this indicate that the kettle is discharging to the adjacent stream. When the green line is flat at approximately 434 feet (132 m), the kettle is dry. 2) Water levels in the well and kettle increase in response to precipitation/recharge on Oct 28th. 3) Water levels in the kettle and well recess. 4) Rate of decline increases once kettle stops flowing out outlet. 5) Kettle is dry while water level in well continues to decline. 6) Increase in well water levels due to small precipitation/recharge event, but not high enough to come above base of kettle. 7) Water levels in well increases and kettle temporarily fills in response to precipitation/recharge event. 8) Kettle fills and begins to discharge out outlet, water levels in well increase. 9) Note that water levels follow similar trend, but are at different elevations since well water level represents a composite water level from multiple zones in the aquifer; whereas kettle represents only the upper-most zone in the aquifer.
Figure 1-25 shows the period when a square notched weir was installed in the Brau Kettle outlet channel and used to measure discharge. Calibration of the manual and data recorder measurements was poor with an R-squared error of 0.79 and seepage around the edges of the weir was observed after several months of operation. The discharge estimates should be assumed approximate at best. The kettle and domestic well water level elevation can be seen rising and falling in response to recharge events as described in Figure 1-24. Discharge is observed to have occurred in the wetter winter months when Evapotranspiration is low and recharges rates and water levels are typically highest. Discharge also periodically occurs during the summer and fall for short durations when heavy rains cause significant but temporary increases in water levels. Discharge rates hover in the 500 to 1000 gpm range and peak as high as 3,500 gpm. This would make the kettle a 3rd order spring and fairly large for what is typically observed in New Jersey. Also of interest is that a nearby stream channel (located approximately 100 feet (30 m) to the north and lower in elevation that the base of the kettle) is typically dry when the kettle is actively discharging. This suggests that groundwater flow is highly constrained along joint-controlled flow paths.
Lastly, because springs may be used to determine the health of the aquifer, floral and faunal studies have been conducted throughout New Jersey (biologists and geologists working together, hmmmm. another sign of the apocalypse). Figure 1-26 shows a recent monitoring of Brau Kettle where a brook trout was captured. An additional study by NJGWS, monitors spring chemistry and temperature. Water samples collected between 10/18/2012 and 7/26/2013 show a range of pH between 7.0 and 7.5 with temperature ranging between 8.6 to 12.0 centigrade.

STOP 2a. Dingmans Ferry Spring
Geologic Setting The same as Stop 1. We are still on the northwest flank of Wallpack Ridge formed here by a gentle dip slope of the Onondaga Limestone. In most places, the slope is covered by thin till. Along the Delaware River, glacial and postglacial terraces flank the river. The field stop route will traverse the lower and older part of the Onondaga first followed by a short ascent to the younger part of the formation. The lower part of the Onondaga is non-cherty (similar to that observed at Stop 1-1a) whereas the upper part is very cherty. Large crinoid columnals that define the base of the limestone were observed by Spink (1967) along County Route 560, located about one mile (1.7 km) from the parking area. The columnals were confirmed by the trip leaders and several more were found nearby along strike.
Location – Lower slope of Wallpack Ridge.
Features – Dingmans Ferry spring, large solution joints, Onondaga Limestone (Edgecliff Member) and tufa.
Discussion – The spring (fig. 2-2) flows out of a large solution joint (070°), and emerges from a large opening at the base of a slope break. From here it spills downstream, cascading over a lag of till stones before coalescing into single channel. A very large oak tree (5-foot (1.5 m) diameter) stands sentient next to the spring, drinking its cool water for centuries. Building ruins below near Old Mine Road (fig. 2-1) and a nearby spring box suggest settlers used the spring for potable water. Evidence of Amerind history in the area (Schrabisch, 1915) suggest the refreshing spring water was enjoyed well before this wild area was settled by colonists. Given the proximity of the spring, cave, and chert resource to each other, this area was probably sacred to the Minsi Lenapi that lived along the banks of the Delaware river.
Tufa, porous calcium carbonate (fig. 2-3), covers many of the rocks near the spring. It was deposited by emerging spring water, following a decrease in pressure (subsurface to atmospheric) resulted in the precipitation of CaCO3. Water samples collected by NJGWS show pH values ranging from 7.25 to 7.42 and total dissolved solids ranged from 161 to 179 ppm; all measurements typical for springs in this area.
The nearby creek bed (fig. 2-1) is lower along contour from the spring and is typically dry. Here the Onondaga Limestone forms the creek bed, primarily a bedding-plane dip slope cut by several large solution joints (fig. 2-4). The limestone exposed along the creek bed is a thin to medium-bedded, faintly nodular, non-cherty limestone with some fossils. Its lithology is similar to the Onondaga observed at Stop 1a, so it may belong to the Edgecliff member. Similar to the situation at Brau Kettle, the lower and dry creek next to the spring shows that groundwater flows along strata-bound solution joints. Upstream a few small seeps discharge into the channel and a small wetland also drains into the channel as well as a small stream that flows off the hill-slope above the spring and well above the Schoharie – Onondaga contact. Present hydrologic conditions do not explain erosion observed along the creek. Perhaps the channel may have been cut by glacial meltwater or postglacial stream flow prior to a change in subsurface drainage and the formation of Dingmans Ferry spring.
Recently, the spring’s small stream was diverted to a larger channel (fig. 2-1). Spring discharge can now be observed flowing into the dry channel just upstream from the culvert on Old Mine Road. This manmade diversion was in response to erosion abatement and icing along Old Mine Road.
Proceed across dry (hopefully) creek bed and head upslope. Safety Alert. Be very careful crossing channel. If wet, the sloping rock surface is very slippery and may also be covered by leaves and moss. Also, watch out for a paper wasp nest near the south side of the dry creek. Hopefully, these insects will vacate the premises before our trip.

STOP 2b. Amerind chert use, Tom Quick Cave, Cherty Onondaga limestone
Geologic Setting The same as Stop 1. We are still on the northwest flank of Wallpack Ridge formed here by a gentle dip slope of the Onondaga Limestone. In most places, the slope is covered by thin till. Along the Delaware River, glacial and postglacial terraces flank the river. The field stop route will traverse the lower and older part of the Onondaga first followed by a short ascent to the younger part of the formation. The lower part of the Onondaga is non-cherty (similar to that observed at Stop 1-1a) whereas the upper part is very cherty. Large crinoid columnals that define the base of the limestone were observed by Spink (1967) along County Route 560, located about one mile (1.7 km) from the parking area. The columnals were confirmed by the trip leaders and several more were found nearby along strike.
Location – Hill overlooking the Delaware River near Dingmans Ferry and the only privately owned toll bridge across the Delaware River. Add history of Dingmans Ferry.
Features - there are three things to see, 2b-1) possible evidence of Amerind chert utilization, 2b-2) Tom Quick Cave, and 2b-3) cherty Onondaga Limestone (flinty Don). Depending on the group size, slope conditions, and whether we’re on schedule, we may stop at all three locations (fig. 2-1). Discussion -
2b-1 – Slope below outcrop.
There are many small chert fragments and a quartzite hammerstone (fig. 2-5) near the base of a tree. Because tree root growth may concentrate rock fragments on the surface (old mapping trick in areas of sparse outcrop), their occurrence here may not indicate Amerind working of this chert resource. However, some chert fragments exhibit conchoidal fractures and the hammerstone’s tip has been broken in a way to suggest it was used as a tool. Also, the hammerstone fits remarkably well into the palm of your hand. Amerinds quarried and collected chert throughout Wallpack Ridge to provide blanks for tools and projectile points (Phillip LaPorta, personal communication, 1996)). Given the location of this hill overlooking the Delaware River, proximity to Amerind encampments situated on alluvial terraces near Dingmans Ferry (Schrabisch, 1915), and abundance of chert in the Onondaga here, this site would have been a prime location to collect chert. It may have been quarried from the outcrop or collected from loose rock on the slope below. Typically, larger pieces of chert were knapped into smaller blanks at the outcrop and then carried back to encampments where they were further worked into tools such as scrappers and projectile points. Hopefully, the evidence presented shows that this site was actively used to process chert. At least that’s our story (spring, cave, chert) and we’re sticking by it.
2b-2 – Tom Quick cave.
The cave is a long, narrow slot (fig. 2-6) that runs about 25 feet (8 m) along a large joint (027°). Given the attitude of bedding (043° 12° NW) and proximity to a steep slope down dip, the cave is probably a fracture cave that formed when a very large joint block moved downslope by creep., and not the result of solution weathering. However, the initial enlargement of the joint by solution weathering cannot be discounted. In addition to creep, movement may have been aided by root growth and ice wedging. Also, evidence for solution weathering beneath cherty limestone (Stop 2b-3) may have contributed to detachment along bedding along the base of the joint block. Above the cave small sinkholes are found that are aligned along the 027° fracture.
Eye witness accounts (Bathgate, 1916) of a small room at the cave’s terminus about 55 feet from its entrance suggest the cave may have been larger than its current size. During a return visit, Bathgate could only proceed about 20 feet into the cave. One of the cave walls had moved closing off the passage. This account suggests that the cave may consist of several joint blocks that at times may move independently from one another.
As with most caves, local lore provides interesting stories where fact is not easily separated from fiction. The cave is named after Tom Quick Jr., who may have used the cave as a hideout during the mid-1700’s following one or several Indian skirmishes (Dalton, 1967). Supposedly, Tom’s father, Tom Quick Sr. was mortally wounded in a raid when the family was cutting ice on the Delaware River (njherald.com/article/20151206/ARTICLE/312069975#).
Currently the cave is closed by the National Park Service in order to protect bats from a deadly fungus that causes white nose syndrome.
2b-3 – Cherty Onondaga Limestone outcrop along west side of hill.
This face offers a good opportunity to investigate the cherty beds of the upper Onondaga. Originally named the Corniferous Limestone (Cook, 1868) based on similarities cherty limestones found in Pennsylvania and New York. This 14 foot-high (4.3 m) outcrop shows an abundance of chert nodules dispersed throughout the outcrop (figure 2-7). The chert nodules vary from 2 to 3 inches (5-7.5 cm) across. Close inspection shows areas where the chertification was incomplete yielding a dark gray mottled appearance. Associated with this incomplete certification are intriguing very thin parallel black curving lines that are commonly associated with the mottled spots (fig. 2-7, inset photos). There is no preferred orientation of these thin bands, which we suggest may relate to the secondary chert-forming process. Further study is needed to completely understand this appearance.
Due to the absence of a preferred fracturing in these beds the chert would be more easily worked and highly prized by the original inhabitants of this region. Farther to the north this same cherty upper part of the Onondaga is highly cleaved which would greatly inhibit the ability to work those cherts into usable points. Beds are generally wavy with variable thickness of 3 to 8 inches (7.6-20.3 cm). At the base of this outcrop are two small solution openings (fig. 2-8) in generally chert-free beds. The solution appears to occur at the intersection of the bedding plane and some weakly developed joints trending 068°. This minor bedding plane solution may have enhanced joint-block movement down slope which led to the development of Tom Quick cave.
Given its high chert content and younger stratigraphic position relative to the basal Onondaga, we believe we are looking at the Moorehouse Member (possibly its upper part). We have not encountered the Nedrow Member in our mapping because it may not be here because it may be indistinguishable from the Edgecliff or Moorehouse Members (Oliver, 1956) or because of its shaly nature it does not outcrop along the Onondaga dip slope. The Tioga bentonite, which defines the Seneca-Moorehouse contact has not yet been encountered in western New Jersey, but as stated in the long discussion preceding Stop 1a we believe the Seneca lies mostly buried beneath alluvium and glacial outwash making its identification problematic.

Peters Valley School of Craft - Lunch Stop
Peters Valley, which is on route to Stop 3 (Bevans Rock Shelter). Park in upper lot near picnic pavilion (fig. 2-9). Rest rooms are located at the bottom of the hill across the street from the gallery. Please take a moment to stop by the gallery and checkout the many fine works of the local artisans.
Peters Valley School of Craft is a non-profit corporation, founded in 1970 in partnership with the National Park Service to promote and encourage education and excellence in craft. Peters Valley School of Craft's programs include adult summer workshops, youth programs, opportunities for artists, special studio programs, public exhibitions, demonstrations, and outreach. Peters Valley School of Craft maintains studios in eight disciplines: blacksmithing, ceramics, fiber surface design, fiber structure, fine metals, photography, special topics and woodworking. Description from https://www.nps.gov/dewa/planyourvisit/peters-valley.htm.
For more information about Peters Valley School of Craft and the programs offered, visit the campus at 19 Kuhn Road, Layton, NJ 07851, call (973) 948-5202 or visit their website at petersvalley.org.
We’ll probably spend about 45 minutes here and then take the short drive over to Stop 3 (Bevans Rock Shelter). Turn right onto Wallpack Road to continue trip.

STOP 3. Bevans Rock Shelter - Parking
Location and logistics Stop 3 is located in the Culvers Gap quadrangle in the Delaware Water Gap National Recreation Area (DEWA) on Wallpack Ridge above Peters Valley (fig. 1-1). The exact location of the rock shelter is not shown in order to protect the cultural integrity of the site. Follow trip leaders to secret parking area and then we’ll proceed by foot to the rock shelter. The large outcrop near the parking area is the Esopus Formation, a very thin to thin-bedded, very fine-grained sandstone. Bedding is 046° 16° NW and the outcrop is cut by a well-developed cleavage (081° 72° SE).
Geologic Setting
The Bevans Rock Shelter (fig. 3-1) sits high on Wallpack Ridge about one mile (1.6) km from both the Delaware River and Flat Brook in Wallpack Valley. The rocks in the shelter area are oldest to youngest are the Glenerie Formation and Ridgely Sandstone of the Oriskany Group, Esopus Formation, Schoharie Formation, and the Onondaga Limestone (fig. 3-2). All formations dip northwestward with the Onondaga forming a long dip slope to the Delaware River. The Ridgely Sandstone, which consists of thick-bedded quartz-pebble conglomerate and coarse quartz sandstone (Monteverde, 1992) may not be present over the Glenerie at the shelter, but it has been observed nearby to the south, where it thickens along strike to Wallpack Bend and reaches a maximum thickness of 32 feet (9.8 m).
Oriskany through Onondaga time represents a sea-level cycle where 1: the Oriskany Group represents a carbonate shelf to clastic sequence (beach and nearshore fluvial deposits), 2: the Esopus Formation represents deeper water deposition marked by very low fossil content and occurrence of the trace fossil Zoophycus, 3: the Schohaire Formation is a transitional unit that marks a return to shallower seas, and 4: the Onondaga represents a carbonate shelf sequence, which in places contains patchwork reefs.
The shelter rocks over the years have had several interpretations. Henry Kummel’s field sheets (1895, on file at NJGWS, Trenton, New Jersey) show that the Cauda Galli Grit (now recognized as Esopus) was mapped at the shelter with the Oriskany contact located just east of the shelter. Meredith Johnson, during a visit to the shelter in 1938 (NJGWS permanent notes on file at NJGWS, Trenton, New Jersey), indicated that the shelter rocks belonged to the Oriskany Limestone. Johnson also noted that base of the shelter contained “numerous small brachiopods of the type similar to Anoplotheca flabellites. Herpers (1952) noted that a contact between the Oriskany and Esopus occurs at the shelter and that the lower fossiliferous zone belongs to the Acrospirifer murchisoni zone of the Oriskany. Monteverde (1992) showed that the shelter lies within the Esopus Formation. Hmmm. multiple interpretations of the same outcrop, let’s see if we can add to the confusion.
Discussion
Geology of Bevans rock shelter.
Take ten geologists to an outcrop and you’ll wind up with 10 different interpretations. An old witticism to be sure, but one with a kernel of truth to it. Who’s right and who’s wrong? We’ll present the facts and you can make up your own minds. Esopus, Oriskany, or both?
The outcrop at Bevans rock shelter looks much different than the Esopus outcrop near the parking area and above the shelter, which is a dark gray, non-calcareous, very fine-grained sandstone with a well-formed cleavage. The trace fossil Zoophycos is also found throughout the shelter’s rocks. The shelter’s roof rock (fig. 3-1) is similarly described so we’re confident that this part of the shelter is Esopus. The 10.5 feet (3.2 m) section (fig. 3-1) below the roof is much different. The rock here is mostly (we did not check every bed) a thin- to medium-bedded, calcareous, very fine-grained sandstone where cleavage is not nearly as well-formed as it is in the overlying rocks. Throughout the shelter’s back wall solution voids up to 6 inches (15 cm) in diameter (most are less than 2 inches (5 cm)) are found along bedding (fig. 3-3). Also, a few dark gray, calcareous concretions (fig. 3-3) occur along bedding about midpoint between the shelter’s roof and floor. Zoophycos occurs throughout this section to at least 2 feet above the shelter’s floor (fig 3-4). Lastly, a thin bed of small brachiopods (fig. 3-3) occurs about 5.4 feet (1.6 m) from the shelter’s floor. Presumably, these are the same brachiopods observed by Johnson and Herpers, which were interpreted to be Oriskany fauna (fig. 3-3). Biostratigraphically, this is a mixed zone where Oriskany and Esopus faunas are transitional. Lithostratigraphically, a contact occurs between non-calcareous and calcareous sandstone at or just below the shelter’s roof. As far as we are aware, no one has described Zoophycos in the Oriskany. However, Brett and others (2009) indicated that a few Oriskany brachiopods were transitional into the Esopus. Spink (1967) also noted, that the lower Esopus contact in places is “gradational through an interval of several feet in which arenaceous and calcareous siltstones become interbedded with, and then are replaced by, silty limestones.” Spink’s silty limestones are probably the Glenerie Formation.
Given the best available data (one of Don’s favorite terms of escapism) and similarity to Spink’s description of the Esopus-Glenerie contact, the shelter section below the roof represents the basal, transitional facies of the Esopus Formation. The Oriskany contact lies just to the east, buried beneath a bog that flanks the shelter. However, if you want to place the contact elsewhere, that’s fine, just publish your work after we retire.
Geomorphology
The rock shelter and the smaller caves on its flanks (fig. 3-5) were shaped by glacial erosion and postglacial mass weathering. The main shelter, with its resistant Esopus roof, was chiefly formed where the easily eroded transitional Esopus rock was removed by glacial plucking and abrasion. The scalloped surfaces on the shelter’s back wall (fig. 3-3f) appear to be glacially scoured. Also, the absence of loose rock beneath most of the shelter’s roof suggests this material was removed by glacial erosion. Admittedly, some of this material may lie buried in the bog that lies adjacent to the shelter. However, given the large size of current joint blocks in and around the shelter, one would expect that some of this material should be here on the floor of the open part of the shelter. Other than smaller stones, this material was probably not moved by the shelter’s past inhabitants.
Over time, part of the shelter’s roof and walls have collapsed (specifically the north end). The result of postglacial frost wedging and slump where joint blocks became dislodged and fell away from the outcrop. Similarly, the fracture caves on the shelter’s flanks may have been formed by frost wedging. However, because bedding dips into the hillside, the movement of these very large joint blocks was not helped by gravity as it was at Tom Quick Cave (Stop 2-c). Another possibility is that ice wedging may have occurred during glaciation. Specifically, during deglaciation when overlying ice was thin and freeze-thaw cycles much more robust.
The smaller cave in the shelter (fig. 3-5) appears to be largely a result of mechanical weathering along a nearly vertical 096° joint that intersects the shelters back wall. However, dissolution in the lower Esopus beds may have aided the cave’s formation. Archaeology of the Bevans Rock Shelter
The Beans rock shelter (fig. 3-6), located in Sandyston Township, Sussex County is a prominent rock shelter that was used by Native Americans during the Late Archaic (3000 B.C to 1000 B.C.) and Woodland (1000 B.C. to 1550 A.D.) periods. This rock shelter sits about 300 feet (91 m) above the Delaware River, located halfway between the Delaware and Wallpack Valleys. The shelter has an eastern exposure and lies adjacent to a narrow bog. It has an overhanging roof that projects up to 20 feet outward from the rock face, creating a sheltered space underneath. The habitable area of the shelter consists of three parts (fig. 3-7). To the south (near fireplaces “a” and “b”) lies a typical overhanging rock, 24 feet long, which projects eight feet outward about 10-14 feet above the floor. In the center (near dislodged rocks), another overhanging rock, 22 feet long, has a roof 8 feet high projecting 6 feet, and is protected in front by two detached masses of rock, one small, the other large, lying 5 feet from the rear wall. The central section has a higher degree of enclosure due to the two detached blocks which hold up the roof and form the eastern wall. At the right is a cave-like compartment (near fireplaces c and d), 16 feet long, 4 1/2 feet wide and 6 feet high. This northern section offers the most protection. All three parts lie in an approximate straight line at the foot of a low cliff and their total length is about 62 feet. The dirt floor underneath the rock is level and composed of light sand mixed with rocks. Two archaeological surveys were conducted here, one from 1912-1913 by Max Schrabisch, archaeologist and writer and another in 1931 led by Dorothy Cross (State Archaeologist and Curator for the New Jersey State Museum). Several local collectors also reported finding material in the main shelter from time to time, but none of this was officially recorded.
Max Schrabisch partially excavated the Bevans rock shelter while making an archaeological survey of Sussex County for the state from 1912 - 1913. In the summer of 1931, from June 8 to July 7, the New Jersey State Museum and the University Museum, Philadelphia, sponsored the complete excavation of the four shelters at the Bevans Rock shelter under the direction of Dorothy Cross. These two surveys uncovered many artifacts or traces of human habitation. During the first excavation by Schrabisch, the southern open shelter (location b, fig. 3-7) yielded the most aboriginal remains while the middle section contained the least. The rear was smoke-stained and discolored by ancient fires but no relics were found on the surface. Native American relics were found from three inches to two feet below the surface. Items included both plain and ornamented pot shards, deer bones, projectile points (identified as arrow and spear points), multiple tools (drill, pestles, hammers, blades), net sinkers, many flint and jasper flakes, and at least 1000 pieces of pottery (most cord-marked) belonging probably to approximately 20 different pots were found in the three parts of this rock shelter. Also, several fire pits were excavated (fig. 3-7), some of which contained mussel shells. Figures 3-8 and 3-9 are some of the artifacts collected during the Schrabisch survey.
A second excavation was conducted in 1931 Led by archaeologist Dorothy Cross (fig. 3-10). Altogether, the second excavation produced 102 various stone artifacts (some of which included arrow points, blades, scrappers, one possible hoe, hammerstones, net sinkers, one maul, one anvil, and one rubbing stone), 11 bone artifacts, 1,428 potsherds (both cord-marked and plain), 100 fresh-water Unio shells (whole and fragmentary), three crinoid stems (possibly used as jewelry) and several thousand whole and fragmentary animal bones, a fragment of a trade pipe, and a lead bullet. Three undisturbed pits were found during this excavation. All pits showed traces of fire action and contained refuse material.
Both archaeologists who excavated the site came to different conclusions about the habitation of the site. According to Schrabisch, “based on the materials found here, the rock shelter was tenanted more or less permanently and perhaps used for winter quarters. The fireplaces suggest cooking and the pottery indicates that the women and children accompanied the men and shared their quarters.” Cross believed “the Bevans shelters were used as temporary abodes and this is attested to by the absence of permanent household equipment. Almost all of the artifacts can be associated with hunting and fishing, either directly or indirectly; though the number of potsherds is a little greater than would have been associated with a hunting or fishing camp.” Cross further stated that “if the entire contents of the shelter were available, more definite conclusions might be drawn” regarding Amerind habitation.

Bevans Rock Shelter

STOP 4. Montague Mini Mall, Montague, NJ
Location and logistics
Stop 4 is located in the Milford quadrangle along Clove Road behind the Montague Mini Mall (fig. 4-1). An exposure of the Coeymans Limestone was uncovered during quadrangle-scale mapping around 1990. A short discussion will precede a good look at this unique exposure. Please do not use your hammers at this site. We wish to protect the outcrop from further degradation so others can also enjoy this interesting outcrop.
Fractures and Weathering
This outcrop was originally excavated in the 1980’s during the construction of a self-storage facility. Since its initial exposure, the outcrop has been weathering fairly rapidly. Both regional strike and cross strike joints were originally evident across these fossil-rich carbonate beds. The strike joints, probably through dissolution and freeze thaw have forced large carbonate joint blocks to break away. Some, I am sure have been picked up for ornamental rocks in personal gardens. Only a single strike joint is visible on the back of the outcrop in the trees. However, a nice cross joint which exposes several thick calcite-filled veins lies near the southern part of this rock body (figure 4-2). The calcite veins appeared to have dissolved faster than the surrounding bedrock which enhanced the formation of large loose blocks.
Even though the fractures here tie in with the main theme of this trip, they were just used as bait to allow us to include this field stop. So read on through the following explanation and enjoy an unusual carbonate outcrop in northwestern New Jersey.
Regional Geology
Rocks of Middle Silurian through Lower Devonian age trend northeast-southwest across northwestern New Jersey (figure 4-2). To the east, gentle, upright folds occur in the Middle to Upper Silurian Shawangunk Formation and Upper Silurian Bloomsburg Red Bed. Moving up section and still eastward of our present location, lies the Upper Silurian through Lower Devonian Poxono Island Formation, Bossardville Limestone, Decker and Rondout Formations and Manlius Limestone. All are locally covered by surficial deposits. The Lower Devonian Coeymans Formation, the lower part of the Helderberg Group, is exposed in front of us. Continuing westward and sparsely exposed lies the rest of the Helderberg Group including from oldest to youngest, the Kalkberg Limestone, New Scotland and Alsen Formations and Port Ewen Shale. As one migrates still farther westward towards the Delaware River the successively younger northwest-dipping units consist of the Glenerie Formation of the Oriskany Group, Esopus (seen at stop 3) and Schoharie Formations, the Onondaga Limestone (seen at stops 1 and 2) and lastly the Marcellus Shale. Regional investigations suggest that the Bloomsburg is the youngest folded unit while the remaining younger unfolded units dip gently northwestward (Monteverde, 1992, Monteverde and Epstein, unpublished data, Drake and others, 1996). Folds in these units reappear immediately south of Wallpack Center (Monteverde, 1992) and to the north across the New York state line into Port Jervis.
Silurian and Early Devonian sediments record the paleoenvironmental change from the end of the Taconic Orogeny into the oncoming Acadian Orogeny. Workers have mapped the changing continental sediments of the Shawangunk into the marginal marine sediments of the Bloomsburg Red Beds (Epstein and Epstein, 1969, 1972). The Bloomsburg displays different sedimentary assemblages indicative of fluvial, estuarine, lagoonal, tidal flat and offshore bar and beach paleoenvironments. These rocks continue to grade upwards into the Poxono Island and Bossardville that mark the continuing transgression through a brackish supra-tidal and intertidal flats depositional environment into a carbonate depositional environment (Epstein and others, 1967; Barnett, 1970, Epstein, 1986). The overlying Decker Formation witnessed a developed carbonate shelf with minor clastic sediment influx as well as locally developed biostromal reef complexes consisting of possible corals + stromatoporoids(?). Time progressed and the sediments of the Rondout mark a relative sea level fall into restricted lagoonal and tidal flat paleoenvironments (Herpers, 1951; Epstein and others, 1967; Epstein and Epstein, 1969). Denkler and Harris (1988) used conodonts from the Rondout to identify the Silurian to Devonian boundary.
Sediments of the overlying lower part of the Helderberg Group record a deepening and corresponding marine transgression. The Manlius Limestone suggests changes from lagoonal and intertidal environments to the high-energy conditions of a carbonate shelf/ shoal and associated patch reefs of the Coeymans Formation (Epstein and others, 1967; Barnett, 1970; Smosna, 1989). Succeeding deeper shelf settings are observed in the Kalkberg sediments and into the argillaceous limestones of the New Scotland Formation (figure 4-3). In this region the overlying Alsen Formation records a minor regression and redeposition of fossiliferous cherty limestone. The same regression is marked in eastern New York by crinoidal grainstones of the Becraft Limestone. Sea level returned to subtidal conditions as shown by the Port Ewen Shale sediments (Barnett, 1970), which marked the end of the Helderberg Group deposition.
Epstein and others (1967) subdivided the different Helderberg formations into members from eastern Pennsylvania to southern New York (figure 4-4). The different members highlight the regionally shifting paleoenvironment along this carbonate margin. Because the descriptive terminology of carbonate units differs from clastic units, one not actively working in these units may become confused with respect to their meaning. Therefore, figure 4-5 outlines the terminology originally devised by Dunham, (1962), and subsequently modified by Embry and Klovan, (1971) so a non-carbonate geologist can understand the meaning of the discussion.
The Shawnee Island Member of the Coeymans Formation is the sole unit exposed at this stop. In the woods to the east the older Thacher Member of the Manlius Limestone is exposed. he overlying Kalkberg and New Scotland locally emerge from the Pleistocene cover to allow their mapping along strike to the northwest and southwest.
Patch Reefs and Flank Paleoenvironments
Along its outcrop belt from eastern Pennsylvania through western New Jersey, eastern New York and westward into central New York, the Coeymans Formation contains at least 14 isolated reef deposits (Oliver, 1960; Rickard, 1962; Epstein and others, 1967; Isaacson and Curran, 1981; Precht, 1982, 1984, 1989; Smosna, 1989). Nine-reefs have been documented in the Deansboro Member of the Coeymans Formation in the Syracuse, New York region and the remaining are in the Shawnee Island Member in northeastern Pennsylvania and northwestern New Jersey (figure 4-6). Each Shawnee Island build up is a patch reef with a central core ranging up to 160x70 m and 15 m thick, accompanied by associated flank beds (figure 4-7) (Epstein and others, 1967; Precht, 1982, 1984, 1989; Finks and Raffoni, 1989; Raffoni and Finks, 1989).
Flank Beds
Reef flank facies consist of bedded bioclastic reef debris that thin away from the reef proper (James and Bourque, 1992) (fig. 4-7). Wilson (1975) differentiates two separate facies, that of flank beds and talus. Bioclastic debris is the exclusive sediment of flank beds, while talus also contains lithoclastic material. Lithoclastic material consists of partially lithified micritic material ripped up from underlying beds. Talus facies deposits are rare compared to flank bed facies (Wilson, 1975). Tucker and Wright (1990) suggest that these flank deposits only form near wave base and are therefore grainstone dominated. High energy waves and currents washed over these skeletal debris deposits and removed all micritic material (Smosna, 1989).
Reef flanks, as seen here, contain a high content of reef debris. This material lies broken and fragmented without any accompanying micritic or lithoclastic material. Fragmental hemispherical Favosites and crinoids constitute the greatest percentage of debris (fig. 4-7). Scarce stromatoporoids are also exposed. Rare brachiopods are present, though I have yet to find any good examples. Crinoids, although not typically part of a reef complex, are exposed here as broken fragments that commonly weather in relief. The character of the limestone beds indicates a reef flank paleoenvironment. The absence of micritic material and lithoclasts suggests an environment above wave base, in strong currents, but not reef proximal enough to be considered talus. The corresponding reef could be south of this exposure as indicated by this outcrops apparent coarser grain size in that direction. Finks (oral communication, 2001) suggested that this site is proximal to a patch reef, currently not exposed.
Relative abundance of the different bioclastic material varies over the outcrop. Corals exist across the outcrop, but they dominate in the southern beds. Crinoids occur as dispersed debris and also concentrated as bed load. They are moderately sorted in the absence of coralline material. Stromatoporoids, distantly related to modern sponges are less common across the exposure.
Grain size is variable across the exposure with a general north-south trend across the central beds. A rudstone texture from fragmented hemispherical corals appears more common in the south. Across the outcrop towards the north a general grainstone texture developed from smaller coralline debris exits. The oldest beds remain as a wackestone to packstone across the outcrop that changes through younger beds as fragmental crinoid lenses that grade into a bioclastic rudstone. Having trouble following this discussion without a figure showing outcrop geometry

B5: NEW INSIGHTS ON RIFT BASIN DEVELOPMENT AND THE GEOLOGICAL CARBON CYCLE, MASS EXTINCTION, AND CARBON SEQUESTRATION FROM OUTCROPS, AND NEW CORE, DRILL HOLES AND SEISMIC LINES FROM THE NORTHERN NEWARK BASIN (NY AND NJ) - Continued
Paul E. Olsen, Sean T. Kinney, Natalia V. Zakharova
Lamont-Doherty Earth Observatory of Columbia University
Palisades, NY 10968
Roy W. Schlische, Martha O. Withjack
Department of Earth and Planetary Sciences
Piscataway, NJ 08854
Dennis v. Kent
and
David S. Goldberg
Brian E. Slater
New York State Museum
Albany, NY 12230
The Carbon Cycle, Global Environments, and the Sedimentary Record It is a viable theory that in the big picture, much of Earth’s geological record of is, in one way or another, a reflection of changes in the carbon cycle, itself uniquely (as far as we know in THIS solar system) and profoundly a reflection of life. Plausibly, because of the interplay between photosynthesis, weathering, CO2, radiative balance, and the thermal gradient of the crust and mantle, the Earth is the only body around our Sun with granite and plate tectonics (Sleep, 2012) and the only body with an atmosphere with significant O2 (Sleep, 2012). This field trip will view the Newark Basin (Fig. 1) and its sedimentary and biotic record though this lens of the carbon cycle. The fact that there is a Newark rift valley at all and that it is filled with largely red beds reflects this profound difference of our planet compared to our companions. Even the packaging of the Newark Basin sedimentary sequence, which is so profoundly cyclical and clearly paced by variations in the Earth’s orbit, seemingly entirely extrinsic to the intrinsic Earth system, must reflect a very strong, nonlinear amplification by feedbacks between the carbon cycle and climate. Finally, the end-Triassic mass extinction (ETE) appears to be an example of a carbon cycle perturbation caused by tectonics – the eruption of the giant Central Atlantic Magmatic Province (CAMP) pumping CO2 and SO2 into the atmosphere. These same rocks may be part of our effort to sequester anthropogenic CO2, itself a product of combustion of a half a billion years of photosynthetic natural carbon sequestration. The fact that the eruptions could occur at all may be a function of the same thermal gradient reflecting the radiative balance that makes our planet hospitable. Much of the theory of the Earth as it relates to life and the carbon cycle is on the fringe of knowledge, but it is useful to ponder how these things might work in order to frame testable hypotheses that may not only help us understand the Earth system from the seemingly arcane vantage of the Newark basin, but also frame hypotheses that have practical consequence for our future.

B5: NEW INSIGHTS ON RIFT BASIN DEVELOPMENT AND THE GEOLOGICAL CARBON CYCLE, MASS EXTINCTION, AND CARBON SEQUESTRATION FROM OUTCROPS, AND NEW CORE, DRILL HOLES AND SEISMIC LINES FROM THE NORTHERN NEWARK BASIN (NY AND NJ) - Continued

STOP 2-1. Cores, Seismic Lines and Posters at Lamont-Doherty Earth Observatory, Palisades, NY
Here we will examine cores, down-hole logs, seismic profiles, posters, and some fossils mostly from the Rockland portion of the Newark Basin near the northern terminus of the basin. These exhibits are meant to compliment the Stops of Day 1 and are related directly to the new seismic profiles across the basin in Rockland. These will relate directly to the outcrops will see after this stop.
Core TW4 on the Lamont Campus
We will examine the following features of Core TW4: 1) Diabase and xenolith; 2) Possible Lockatong Formation; 3) Nominal Stockton Formation; 4) High gamma sandstones without organics; 5) Gypsum-bearing red beds; Odd purple interval; Contact with Fordham Gneiss.
Core from the Tandem Lot
Metamorphosed lower Passaic Formation: Approximately 150 ft of core was collected from above and close to the Palisade Sill. Core is characterized by the presence of metamorphic minerals, most obviously epidote, and by peculiar colors, such as green and various shades purple and orange (Slater et al., 2012). Anhydrite, quartz, calcite, and feldspar cements are present. Sedimentary fabrics suggest pedogenic nodular carbonates and fluvial or marginal lacustrine environments.
Cuttings and side wall cores from the Tandem Lot
Compare these cuttings and sidewall cores with the equivalent footages on the logs and with the seismic line to get a comprehensive perspective on the 6880 ft Tandem Lot drill hole.
Passaic Formation: Most Passaic formation washed cuttings look like they are nearly 100% sandstone because the mudstones wash out. We will show examples of the comparison between cuttings and sidewall cores.
Palisades Sill: Cuttings displayed will be from: 1) the upper part of the sill near the contact with the Passaic Formation; 2) the high gamma part of the sill plausibly from the zircon-bearing “sandwich horizon”; 3) from the middle part of the sill; 2) and the lower part of the sill, comparable to what is seen in the TW4 core.
Lockatong Formation: The cuttings are easily mistaken for gneiss, but the sidewall cores and FMI logs show that the section below the sill is similar to what we saw at Stops 1.3 and 1.5 consisting of alternating gray and dark mudstones and tan sandstones.
Fossils from the Passaic Formation of Rockland County
Fossils from the old Manhattan Trap Rock Company Quarry at Nyack Beach State Park (Stop 2-2): Large tetrapod, probably reptile burrows; a small theropod dinosaur (brontozoid) track, Grallator sp.; Scoyenia (arthropod) burrows; and rhizoliths (root traces). The Grallator sp. track may be the only definitive dinosaur footprint from New York State.
Fossils from Snedeker's (or Waldberg) Landing, Haverstraw (41.173200°, -73.934633°): A small sandstone quarry located south of Haverstraw Beach State Park has produced a series of quite good and diverse fossils over the decades. On display will be the tetrapod trace fossils and fish scrap shown in Fig. 37, as well as additional Cynodontipus burrows, small very clear Brachychirotherium sp. tracks, and complex rhizomorphs (root traces).

STOP 2-2A. Passaic Formation and Palisade Sill
Passaic Formation and Palisade Sill, Old Manhattan trap Rock Quarry, Nyack Beach State Park, Upper Nyack, NY.
Park vehicles at lot near beach on the Hudson and walk toward the brownstone Dutch colonial-looking “bathhouse” and the adjacent outcrops of Passaic Formation.
Nyack Beach State Park, is the southeastern component of a series of contiguous state parks including Hook Mountain State Park, Rockland Lake State Park, and Haverstraw Beach State Park all contained within Palisades Interstate Park. It hard to see it now, but this park was a huge active trap rock quarry in the nineteenth and early twentieth century (Fig. 38). Quarrying may have begun for the red sandstone at this site by the middle 18th century and the quarry a Station B may have been part of the string of at least 30 (!) quarries extending from Upper Nyack to Piermont at the peak of the operations in the middle 19th century. The “Voorhis” Quarry at this site may have begun as one of these, but by the later 19th century, the quarry was focused on the diabase instead; the production of a higher quality “brownstone” had shifted to the Connecticut Valley (mostly of Jurassic age). In 1872, a huge stone crusher complex was built, eventually extending from the trap rock quarry floor to the river, filling the sandstone quarry as part of the Manhattan Trap Rock Company (OPRHP, 2013). The blasted diabase was dumped from the quarry floor (Station C) into the steam-engine-powered-crusher and sorting system and conveyed via belts down to a cement structure (still extant) on the north side of the brownstone powerhouse and then out on a long raised double pier where the crushed stone was loaded onto freighters on the Hudson (Fig. 38A). By the 1890s, the destruction of the Palisades cliffs and the associated blasting and crushing noise at Hook Mountain and elsewhere had become a conservation cause. In 1906, the authority of the Palisades Interstate Park Commission (the impetus for which was led by The New Jersey Federation of Women’s Clubs) was extended by legislative action to Hook Mountain and north, and by contributions from members of the Rockefeller (the estate – Kykuit - of which was opposite the quarry), Harriman, and Perkins families, the Hook Mountain area and its quarries were purchased by the commission – ending quarrying by 1912. Many buildings of the complex were removed as was the rock crushing equipment, making the sandstone quarry again accessible (Fig. 38B). The Work Progress Administration (WPA) repurposed and rehabbed the powerhouse in 1936 as a bathhouse with a large fireplace and ballroom (OPRHP, 2013), which is the structure visible today at Station A.
The most extensive description of the geological aspects of the quarry was made by Kümmell (1900) when the Manhattan Trap Rock Company was operating at full-bore. Kümmell (pp. 27-28) notes: “At the time of my visit, the trap at the south end of the quarry could be seen cutting across the sandstone obliquely downward to the north, a distance of about 35 feet in 60. Thence it followed conformably the bedding planes and gradually regained its former elevation above sea level, though still at a lower geologic horizon. Its general elevation at the quarry is about 260 feet A. T. If the base of the trap kept to the same horizon which it has where it turns so abruptly eastward at Verdrietege Hook, the rise of the underlying sandstones up the dip would carry it from 620 to 6601 feet higher above sea level than it actually is at the quarry. The evidence seems conclusive therefore that the abrupt turn at Hook mountain north of Nyack, is due to the descent of the base of the sheet to a geologic horizon 600 or 700 feet lower than that occupied where it crosses the Rockland Lake-Nyack road.” These observations are very important because they show that the crescentic offset of the Palisade ridge is not due to an anticline as sometimes presumed, but rather by the change in stratigraphic level intruded. Unfortunately, very few other detailed observations have been published on the extensive remaining aspects of the site, except for Savage (1968), and in fact the large sandstone quarry at Station B, seems to have escaped geologists’ attention entirely until brought to the attention by Dr. William Menke (Columbia University) who found it while hiking. There are no published observations on the paleontology for the Passaic Formation at this site.
Station A. The handsome brownstone “bathhouse” is the repurposed part of the Manhattan Trap Rock Company complex of buildings. The tall brownstone tower-like structure on the south side of the building was the base of a large smokestack of the steam powerhouse of the plant (anonymous, 2011). We presume the sandstone for this building came from the quarry at Stop 2-2, Station B (below). Exposures behind the “bathhouse” are the lowest in this area and consist of a complex of bioturbated mudstones, micaceous reddish-brown sandstone, and some greenish-gray arkose (Savage, 1964). Some surfaces have dessication cracks and less disrupted clay bedding surfaces that could have tetrapod tracks. Carbonate nodules are present and carbonate and mud pellet intraformational conglomerates are present at the bases of some of the sandstones. According to Savage (1964) the paleocurrents are towards the northeast here, characteristic of many exposures in the Rockland part of the Newark Basin where they generally have easterly directions. This is distinctly different, as is the mineralogy, from the Stockton Formation as seen at Snedens landing where the paleocurrents are largely towards the west (Savage, 1964; Olsen, 1980b). Completely absent at this and the other exposures at this site are the red-purple massive mudstones with the very large ptygmatic arkose-filled dessication cracks seen in TW4 core and exposures at Stop 2.2, consistent with this section being upsection from those near the state-line.
From Station A walk 112 m SW along entry road to end of wall on right side of road. Turn northeast and walk up macadam path 39 m to entrance to trail at 41.120394°, -73.912492°. Walk 54 m northeast and turn sharp left up switchback trail. Walk 57 m southwest to right turn. Walk 90 m northeast to path to quarry. Go 41 m northeast into middle of old sandstone quarry.

STOP 2-2B. Old Sandstone Quarry
This sandstone quarry was previously filled by the crusher complex of the Manhattan Trap Rock Company of the late 19th and early 20th century and prior to that it may have been the Voorhis sandstone quarry. More than 50 m of red mudstone and red and some tan sandstone are exposed. Fossils are abundant in the rubble from the quarry along its edges and down the slope to the east. Beware of broken glass, etc. Fossils are common (Fig. 39). Scoyenia (arthropod) burrows and clay rhizoliths (root traces) are abundant, sometimes obliterating bedding. At least one brontozooid dinosaur track, Grallator sp., has been found along with one bone fragment. But most striking are the large flattened burrows, 10 to 15 cm wide, that are surprisingly common (four visits with four finds). We identified similar flattened cylindrical features as large roots at Stop 2.3, but they differ from roots in maintaining a relatively constant diameter and not branching. Instead they are consistent with tetrapod burrows. Such burrows indicate that these strata have intervals when they were above the water table for significant amounts of time. It is possible that skeletal remains could be found in such burrows and one should be alert to that possibility when looking about.
The section has several laterally persistent intervals of thin bedded siltstone and sandstone suggestive of shallow water lacustrine intervals seen in the Passaic Formation near Milford, NJ., and it is possible these were deposited during the wet phases of climatic precessionally paced Van Houten cycles.
Looking west and up towards the top of the quarry, you can see the remains of the cement portals for chutes from the trap rock quarry itself. These can be seen in Fig. 38B. The adjacent mudstones have a gray or purplish tint and the sandstones are large tan. We will see this again at Station C and the colors might be most simply explained by metamorphism approaching the sill contact.
Time permitting, we will leave the sandstone quarry and continue up the trail to the road up to the upper parking area.
Return 90 m southwest from middle of quarry and then 138 m southwest to switchback turn. Turn right and go 119 m to chair at last switchback turn before road. Turn left and go 98 m to entrance onto road. Turn right and walk northeast up road to parking area.

STOP 2-2C. Trap Rock Quarry
The upper parking area at Nyack Beach State Park occupies the former floor of the main part of the Manhattan Trap Rock Company Quarry. Observe jointing in sill: is this columnar jointing? At the far northern end of the quarry a “rotten” zone of diabase typical of the olivine zone of the sheet (Walker, 1969; Steiner, 1989).
Walk 90 m southwest to electrical service boxes. On right (northwest) 26 m is a continuous exposure on a promontory of metamorphosed Passaic Formation to the oblique, down to the west, contact with the Palisade Sill. Exposure is at 41.121486°, -73.913278°.
From the electrical boxes, proceed 44 m southwest to stone bathroom. Most of the blocks of this building are metamorphosed Passaic Formation. Many blocks exhibit nodular zones with epidote, presumably replacing carbonates. Walk back to electrical service boxes and go right down steps to road.

Parking for stop 2-3

STOP 2-3. Passaic Formation above Palisade Sill
Park vehicles on unpaved road and proceed 294 m south along N Greenbush Rd to break in vegetation at 41.083084°, -73.946247°. Proceed southwest 34 m at 232° (true N) to 41.084403°, -73.946810°, adjacent to large bedding surfaces. Proceed 54 m due west to a point (41.083117°, -73.946887°) on the bedding plane surface near the “discovery site” for the area.
Reptile footprints were originally found during reconnaissance of excavated rock surface by Paul Olsen and Robert F. Salvia in fall of 1972. Fossils were removed shortly thereafter and deposited in the State Museum of New York, in the case of footprints, and Yale University, in the case of bone and teeth fragments. After initial discovery and salvage, no more material was found until the preparation of this report. Excavation of the site for fill occurred prior to and had ceased by the time of the fossil discovery and since that time the site has lain fallow and is now partly covered by vegetation. However, much bedrock remains exposed.
The site consists of series of large bedding plane (dip slope) exposures comprised of variegated (gray, tan, purplish, greenish, and red) slightly metamorphosed mudstone and siltstone and arkosic sandstone of the Passaic Formation. The stratigraphic level may be correlative with one of the gray sequences further to the southwest within the basin. The Palisades Sill outcrops to the east, north, and south of the site. From the attitude of the outcropping adjacent diabase on north, south, and east sides, it appears to be strongly discordant, cutting though the Passaic Formation at a high angle. Judging from what is known elsewhere where there are similar contacts and based on the visible metamorphism of the bedrock, the Palisades diabase probably underlies the Passaic Formation at this site at some depth, probably more than 10 feet and probably less that 500 feet.
Four basic classes of fossils were found at the site: 1) reptile footprints; 2) tetrapod burrows; 3) possible teeth and bone scraps; and 4) rhizomorphs (natural casts of plant roots). Two areas you can see most of these features are centered at a north area (A: 41.083347°, -73.947186°) and a south area (B: 41.082287°, -73.946835°) with a 25 m radius.
1) Reptile Footprints: Reptile footprints were found in three places at the site. The first, “the discovery slab” was found in place with all of the tracks filled with white sandstone (Fig. 40) close to 41.083117°, -73.946887°. It was quarried out, taken to the New York State Museum and reassembled by the exhibition staff (briefly described by Olsen & Flynn, 1989). We (Paul Olsen and Robert F. Salvia) subsequently removed the white sandstone fill of the tracks. The slab in its present state reveal at least 12 three-toed footprints, each measuring about 12- 13 cm long (Fig. 40). The tracks have a shape typically associated with small dinosaurs and in fact they have been cited numerous times in the literature (e.g., Fisher, 1982) as the tracks of the small theropod dinosaur Coelophysis, which they are certainly not. Small coelophysid theropod dinosaurs such as Coelophysis, have a relatively long digit III (middle digit) on the foot producing bronozooid type tracks of the ichnogenus Grallator, but digit III on the tracks in the discovery slab is relatively short. On this basis alone, Coelophysis can be discounted as the track maker, even though coelophysid dinosaurs are known from strata both older and younger than this site in the Chinle Formation of the Southwestern United States (Irmis et al., 2011; Ramezani et al., 2014), and a small bronozooid was been found at stop 2-2 (Fig. 39).
The tracks on the discovery slab (Fig. 40) could belong to one of non-coelophysid dinosaurs known from the late Triassic, a non-dinosaurian dinosauromorph, or even a crocodile line archosaur convergent on dinosaurian form. Non-coelophysid dinosaurs such as the herrersaurid Chindesaurus do occur in North America (Irmis et al., 2007) and something like that could have made the track. However, only Herrersaurus proper has well preserved feet and these have a large digit 1 on the pes that should have impressed, but we do not see that in these tracks.
Atreipus (Olsen & Baird, 1986) is fair match to the footprints on the “discovery” slab in having a tulip-shaped hind track with a relatively short digit III for its size. Although Atreipus is usually found with forefoot impression, it is not rare to see trackways in which no forefoot impressions are present. Unfortunately, the tracks on the discovery slab are not well preserved enough for a positive identification. In any case, Atreipus can now, with some confidence, be assigned to a recently discovered group of non-dinosaurian dinosauromorphs, the silesaurs (such as Silesaurus). It is possible that poposaurs, a group of crocodile-relatives (suchian pseudosuchians) that evolved bipedal very dinosaur-like forms such as Effigia okeeffeae (Nestbitt, 2007), could have made these track, but Effigia too has a large digit 1 and so cannot be simply hypothesized to have made the discovery slab tracks. In summary, the tracks were not made by Coelophysis and may not have been made by a dinosaur.
Two occurrences of probably small quadrupedal forms were found on blocks that had been transported to the west edge of the property abutting Route 303 (Fig. 41). These were collected and given to the New York State Museum, although their present location is unknown. These small tracks probably belong to Brachychirotherium (a distant crocodilian relative that was not dinosaur-like), but they are actually too poorly preserved to identify.
2) Tetrapod burrows: Large cylindrical casts are present (Fig. 41) in a greenish gray silty to fine sandy massive mudstone in the southwestern outcrops. Originally, Paul Olsen thought they were tree roots or trunk, but like the similar forms from Stop 2.2, they do not branch and are more simply interpreted as tetrapod burrows.
3) Possible teeth and bone scraps: A few small teeth and bone fragments were found. The shape of the probable teeth is superficially consistent with a phytosaurian reptile, but the metamorphism renders identification extremely difficult. The possible bone fragments are unidentifiable. These specimens were deposited in the vertebrate paleontology collection of the Peabody Museum of Yale University.
4) Rhizomorphs: A variety of rhizomorphs (root traces) are present throughout the exposed bedrock. These consist of whitish claystone natural casts in a greenish gray, silty to fine sandy massive mudstone (Fig. 41). They are present in most layers, but are especially obvious in the layers with the mapped tetrapod.
There have been several attempts at preserving this area via cooperative agreements between the land owner and Orangetown (the municipality), spearheaded by local residents (e.g., Town of Orangetown, 2009). Thus far, a firm arrangement has not been reached because of unfortunately timed economic downturns.

Tandem lot on left was drilling site.

Parking for Stop 2-4

STOP 2-4. Passaic Fm ss and cgl on Thruway, Monsey, NY.
NB! This site cannot be visited without a permit from the New York State Turnpike Authority and without proper safety attire.
Park vehicles near overpass for turnpike on east side of Saddle River Road. Leave the vehicles and proceed to north side of overpass. Go over fence and proceed east up to highway. At highway, stay to the outside (north) of the barricade and walk along cut to the east.
This cut exposes roughly 25 m of red pebbly sandstone and conglomerate and very minor mudstone. Conglomerates are dominated by Paleozoic sedimentary and metamorphic clasts. Highly irregular bedding with almost no preserved fine scale sedimentary structures, most simply explained by bioturbation by roots and burrows. This section was certainly deposited by fluvial processes, based on the apparent channel forms. This facies is typical of most of the Passaic Formation in the western half of Rockland County.

STOP 2-5. Upper Feltville Fm ss and cgl, lower flows of Preakness Basalt
Upper Feltville Formation sandstone and conglomerate and lower flows of the Preakness Basalt, at former Tilcon, Union Hill Quarry, Village of Sufferen, Town of Ramapo.
As mapped by Volkert (2011) Union Hill is underlain by an outlier of Preakness Basalt in a syncline with the Feltville Formation, Orange Mountain Basalt and uppermost Passaic Formation. Only the upper Feltville and lower Preakness Basalt, in which the trap rock quarry was developed, are exposed here, the rest being covered by Pleistocene till and Holocene deposits except for another small outlying area of basalt. We will examine the section from the top down in three stations, A, B, and C.
Station A. Preakness Basalt: The two lower flows of the Preakness Basalt are well exposed here and very similar to what we saw at Stop 1.8. The lowest flow is irregularly pillowed and the succeeding flow has a massive base and a typical, for the Preakness, entablature with well-developed, platy-prismatic jointing. The top of second flow is not exposed. Ratcliffe (1988) suggested that the western part of the quarry occupies a lower structural level than what is exposed on the east side. He suggested two possibilities: 1) a basalt flow complex flowing in a topographic depression west of the conglomerate; or 2) a westward-dipping or vertical fissure feeder surfacing in flow rocks. Ratcliffe notes that the pillowed zone was exposed at the deepest parts of the quarry so that (2) seems contradicted. This will be discussed on the exposures. However, there is little doubt that distinctive features of the Preakness Basalt, particularly its platy-prismatic jointing are very laterally persistent.
Station B. Contact between Preakness Basalt and Feltville Formation: The contact between the uppermost Feltville Formation was well exposed during quarrying operations and was described by Ratcliffe (1980; 1988). Presently only some ledges of coarse dolostone conglomerate are exposed near where the contact projects. According to Ratcliffe (1980, p. 297), “Superb exposures at the south end of the quarry … show a vertical wall of coarse fanglomerate, enclosing a large boulder of brecciated dolostone in an apparent channel that, in turn, is overlain by an upward-fining cycle ending in fine red shale with greenish slate chips. Vesicular pillow lava directly overlies this shale.” Based on stratigraphic position directly below the lowest flow of the Preakness Basalt, this is time-equivalent to the reddish and gray sandstones and mudstones at Stop 1.8.
Station C. Wall of conglomerate of the upper Feltville Formation: This wall of brown conglomerate is a noticeably different color than typical red conglomerate of the Passaic Formation. According to Ratcliffe (1980, p. 297), “Clasts in the fanglomerate include epidote-rich hornblende granite gneiss, Silurian Green Pond conglomerate, dolostone clasts, and several cobbles of basalt pillows.” Clasts of basalt other than pillows are present as well. The presence of these basalt clasts are evidence that these units are upper Feltville Formation. Volkert (2011) map the presence of Orange Mountain Basalt in this area on the basis of extrapolation from the Cushtunk, NJ area, although there is no direct observational evidence, close to Union Hill. However, Ratcliffe (1988) note that the chemistry of a small basalt outlier 2.4 km northeast of Union Hill (at around 41.133685°, -74.126122°) is indistinguishable from that the upper Ladentown flows to the northeast. The Ladentown flows are in turn part of the Orange Mountain Basalt (Blackburn et al., 2013; cf., Puffer, 1987; Puffer et al., 2009). This small basalt outlier projects to the conjectural Orange Mountain Basalt on the northeast limb of the Union Hill Syncline. That the Orange Mountain Basalt does not outcrop in this area is not indicative however, because it does not outcrop all along the east side of Camgaw Mounatin, where it is mapped by records of numerous water wells (Volkert, 2011). The hypothesized presence of the Orange Mountain Basalt in the Union Hill area could easily be tested by drilling.

Parking for Stop 2-6
Proceed to parking lot of train station and to walkway to Station (41.115038°, -74.154749°). Walk east and southeast 42 m and turn left before the chain link fence. Walk 36 m north-northwest to outcrop.

STOP 2-6. Footwall of the Ramapo Fault Zone, Suffern, NY.
Proceed to parking lot of train station and to walkway to Station (41.115038°, -74.154749°). Walk east and southeast 42 m and turn left before the chain link fence. Walk 36 m north-northwest to outcrop.
This outcrop is described as follows by Ratcliffe (1980) as cataclasite and fault fabric in cataclastic gneiss at Ramapo fault: “These small exposures of black, chlorite-coated, cataclastic, hornblende-granite gneiss are much more instructive than the exposures north of Suffern commonly visited by field trips. Excellent chlorite-slick surfaces dip in conjugate fashion northwest and southeast and exhibit down-to-the south right-oblique slip on southeast-dipping surfaces and down-to-the-west and left-oblique movement on southwest-dipping surfaces. The near-vertical attitude of the extension fractures here … suggests that the rocks of the footwall block … have not undergone rotation after formation of the cataclastic fabric.”
Volkert (2011) mapped this outcrop as Mesoproterozoic hornblende granite of uncertain affinity with abundant xenoliths of well-foliated gneiss. According to Volkert’s map, it is about 330 m northwest from the mapped position of the Ramapo Fault and 75 m northeast from a NW-SE right lateral strike slip fault. Mapped foliations in the hornblende granite are to the southeast 30°-60° and a southeasterly dipping normal fault is shown on the immediate northwest.
It is worth noting that the mapped position of the fault does not correspond to the apparent escarpment of the Ramapo Mountains, and that nearly all outcrops are hundreds of meters within the footwall from it. Because the border faults of the Newark Basin tend to follow pre-existing structures, especially of Paleozoic age, brittle features that may have formed prior to the formation of the Newark basin proper may be hard to differentiate from Late Paleozoic structures. It is noteworthy that the position of the Ramapo Fault cannot be easily seen seismic profile, although that in part may be do to its relatively high angle here, structure parallel to the boundary fault are not as obvious at this site as one might hope.

B6: LATE AND POST-IGNEOUS MINERALIZATION OF THE ORANGE MOUNTAIN BASALT AND THE CO-MAGMATIC PALISADES SILL
John H. Puffer
Dept. of Earth & Environ. Sciences
Emeritus
Rutgers Univ.
Newark, NJ 07102.
Karin A. Block
Dept. of Earth and Atmospheric Sciences
City College of New York
NY 10031
Chris Laskowich
Geologist
14 Old Rifle Camp Road
West Paterson
NJ 07424
Michael Dorsey
Tilcon NY Inc,
162 Old Mill Rd.
West Nyack, NY.
The three Orange Mountain basalt flows are typical in most respects to other occurrences of HTQ-type CAMP basalt. However, some unusual to rare mineralization and structures are associated with the flows. Unusually high quality zeolite mineralization is associated with an Orange Mountain pillowed flow while high quality prehnite is found associated with highly vesiculated subaerial structures and historically important copper mineralization is associated with metasomatism at the base of the first flow. A distinct and uniform 4 m thick black layer at the base of the first flow contains up to 35 volume percent fine grained disseminated calcite and is overlain by a 4 m thick white albite enriched micro-vesicular layer that has locally thickened into diapir shaped structures containing vesicles up to a meter across. We propose that these mineral and structure associations are the result of a complex sequence of high temperature hydrothermal activity heated by the underlying intrusion of co-magmatic Palisades diabase magma and by subsequent low temperature hydrothermal activity associated with later pulses of Palisades magma and by post igneous burial dewatering.
Safety considerations
The field trip accompanying this chapter will include rock quarry sites. Therefore, for your protection, hard hats, steel-toe boots, long pants, and eye-goggles, must be worn while visiting these sites. Stay a safe distance away from quarry or road-cut walls where loose rock may fall, and be sure to wear goggles when trimming rock samples. Be aware that using a steel hammer as a chisel can cause steel splinters to fly off.

B6: LATE AND POST-IGNEOUS MINERALIZATION OF THE ORANGE MOUNTAIN BASALT AND THE CO-MAGMATIC PALISADES SILL

STOP 1. Lower New Street Quarry, Woodland Park, NJ.
The Lower New Street Quarry (Fig. 8) is located in a wooded lot at 100 New Street, Paterson, New Jersey adjacent to Route 80 east, in Passaic County, and is mapped within the Paterson Quadrangle. It is one of several trap-rock quarries cut into the Orange Mountain basalt of New Jersey. High quality specimens of prehnite (Fig. 9), analcime, chabazite, datolite, heulandite, pectolite, natrolite, stilbite, and amethyst have been found in at Lower New Street and in the adjacent Upper New Street quarry located on the east side of New Street. This secondary mineral assemblage in the context of Paterson area trap-rock quarries has been described by Fenner (1910), Schaller (1932), Drake, (1943), Mason (1960), Sassen (1978), Peters et al. (1980), Peters (1984), Cummings (1985, 1987), Kent and Butkowski (2000), Imbriacco (2009, 2010) Sinkankas, J. (1964), Puffer and Student (1992), Puffer and Laskowich (2012), and Laskowich and Puffer (in press).
Subaqueous pillowed OMB2 at base of quarry
At the base of the Lower New Street quarry, in a trench along the south end of the quarry wall, excellent exposures of pillow basalt provide evidence of subaqueous extrusion. Pillows are an important characteristic of the OMB2 flow wherever it has been described. Most of the pillows are large (about one meter across) and are coated with a dark green palagonite rind. Subtle differences in shape and distribution have enabled Manspeizer (1980) to distinguish between pillows, flow lobe pillows, and bedded pillow buds although some of the distinctions among sub-types are based on observation made at other quarries including the Upper New Street quarry that was cut into the OMB2 flow.
Subaerial pahoehoe OMB2 (OMB3?) on quarry wall
Flat pahoehoe surfaces, pahoehoe toes, collapsed and open lava tubes, large lower flow vesicles, and massive to columnar joint systems are exposed along the quarry wall of the Lower New Street quarry. In contrast to the pillows observed in the trench at the base of the quarry the elongate ellipsoidal structures exposed on the quarry wall are here interpreted as subaerial pahoehoe toes. The criteria for distinction between pillows and pahoehoe toes was presented by Manspeizer (1980) as first established by Macdonald (1953):
Pahoehoe toes
Major axis of the ellipsoid 3 or 4 times the cross sectional axis.
Concentric structures in cross section.
Moderately to highly vesicular or amygdaloidal.
Vesicles elongate tangentially to edge or not at all.
Lava tubes are common, resulting in central cavities.
Radial joints are poorly developed or absent.
Pillows
Major axis of ellipsoid less than 3 or 4 times the cross sectional axis.
Radial structures well developed.
Moderately to poorly vesicular or amygdaloidal.
Vesicles elongate radially, especially near the edge.
Lava tubes are rare.
Radial joints are well-developed and conspicuous in cross section.
These criteria continue to be generally accepted among volcanologists. Although not all of the ellipsoid dimensions of the pahoehoe toes exposed on the quarry wall appear to be more than 3 times the cross section axis, the criteria is based on the maximum dimension of the cross section axis which is not typically exposed in outcrop. It is, however, apparent that lava tubes are common across the quarry face. Each of these tubes have been lined to varying degrees with prehnite. Most of these tubes have collapsed or partially collapsed under the weight of late OMB3 flow inflation resulting in horizontal layers of breccia cemented with prehnite.
At a central location on the south-west quarry wall a smooth flat surface dipping northward about 15 degrees is interpreted as a subaerial pahoehoe surface. Similar surfaces are not commonly found throughout the OMB1 and OMB3 flows despite their generally recognized acceptance as subaerial flood basalt flows. The pahoehoe surface exposed here marks the transition of a subaerial flow lobe before it was buried by a thick layer of massive tholeiitic basalt. Some columnar cooling joints are apparent in the upper quarry wall together with large vesicles that are a characteristic of OMB1, again, generally accepted as subaerial.
Secondary Mineralization
In general, the most of the prehnite (Fig. 8) that we have found among Orange Mountain basalt exposures throughout New Jersey is contained within subaerial structures including diapirs, large partially filled vesicles, half-moon vesicles, and vesicular flow-tops (Puffer and Laskowich, 2012). In contrast, the most productive zeolite collecting is largely confined to the pillows of the OMB2 flow with some notable exceptions. The prehnite to zeolites abundance ratio throughout the Lower New Street quarry above the pillow layer is typical of Orange Mountain subaerial exposures elsewhere and is quite high. There is no definitive explanation for this. However, the zeolites found in the Orange Mountain basalt are much more highly hydrated than prehnite and in most cases are sodic in contrast to prehnite which contains calcium as the only significant octahedral cation. Perhaps preferential salt water contamination of the pillowed layers during extrusion is a controlling factor. Geochemical evidence (Puffer and Student, 1992; Tollo and Gottfried, 1992) indicates that the zeolite enriched pillowed portions of OMB2 contain up to 5.34 percent Na2O compared to a typical OMB concentration of 2.4 %.

STOP 2. Very Strange White and Black Layers at base of first Orange Mt basalt flow, Woodland Park, NJ
At Stop 2 we will sample the White and Black layers of OMB1 exposed along Ryle Road at the Paterson Animal Shelter near the north end of Totowa Road (Fig. 9). Large slabs of basalt fallen to the base of the cut allow close inspection of pipe vesicles at the base of the black layer. Note the micro-vesicular texture of the White Layer and the black spherical shaped structures 1 to 3 mm across that comprise about 80% of the Black Layer. They are best observed with a hand lens. These spherical structures were interpreted by Puffer and Laskowich (2012) as collapsed bubbles that formed too early in the cooling history of the basalt to prevent closure of lava behind them.

STOP 3. Orange Mountain Basalt at Great Falls, Paterson, NJ
We plan to stop across from the Libby’s Lunch Restaurant within a three minute walk from the edge of the cliff overlooking Great Falls. Simply walk toward the US flag at the falls (Fig. 10). The upper-middle 70 % of the OMB1 flow is exposed. An abandoned hydroelectric power plant can be seen on the bank of the Passaic River. Common half-moon vesicles are exposed along upper surfaces of basalt.

STOP 4. Tilcon Haverstraw Quarry in Palisades Sill, Haverstraw, NY.
The trap-rock quarry at Haverstraw (Fig. 11) is owned and operated by Tilcon Corp. and is located on the west bank of the Hudson River. We will exit our bus at the mine office located at 66 Scratchup Road.
Tilcon N.Y., part of the Oldcastle Materials group, operates a crushed stone quarry in Haverstraw, New York. The quarry first began mine operations in 1927 and has since expanded to cover 112 acres. The majority of stone crushed in the northern Rockland County quarry ships out on barges down the Hudson River to terminals in New York City and Long Island where it will be used for construction projects including asphalt and concrete.
The quarry produces crushed diabase, known as “trap rock” in the construction industry. The stone is first blasted from the quarry’s rock faces before being crushed by the primary crusher, which is visible from the entrance of the mine. From the primary crusher, stone is sent through a tunnel under Route 9W to the secondary plant where it is crushed and screened to ensure proper size for construction usage/applications. Once the stone passes a quality test, it is transported to customers via trucks or barges.
The quarry sits on the Northern extent of the Palisades sill. The top of the quarry by the radio antenna is 580ft above sea level. The current quarry floor is -220ft. Cores drilled down from this level show another 160ft of diabase before intersecting the lower contact with the Newark group sedimentary sequence (Moore 2015). The diabase is columnar jointed in the south west corner of the quarry and dips sharply in the north east. This sharp dip causes the northeast faces to appear less defined and there is more rubble on the benches. The eastern face also shows evidence of faulting with no displacement. There is evidence of slickensides on some of the rock mined. Inside some of these faults and also in some joints mineralization of primarily calcite occurs (Delcos 2003).
The quarry has exposed both upper and lower contacts between the palisades sill and the surrounding sedimentary rocks of the Newark basin. The lower contact was intersected while constructing a conveyor tunnel under 9W (Delcos 2003). Unfortunately, the contact was covered by concrete upon completion of the tunnel. The upper contact is exposed on one of the uppermost benches on the North West face. This contact has only been recently exposed by mining operations. The upper contact zone is not clearly defined in the quarry. This is evident in The Western side of the mine where overburden is being stripped to expose more diabase. This stripped area has a horst and graben structure making it difficult to find the contact.
The Haverstraw Quarry is one of only two Quarries actively mining the Palisades sill diabase, the other is Tilcon’s West Nyack Quarry.
Probably the first thing that most visitors to the Haverstraw Quarry notice is the impressive depth of the open pit. Thirteen 50 foot benches have been cut into the Palisades Sill that have exposed the lower few meters of the overlying Lockatong Formation (a non-marine meta-siltstone/argillite) and about 700 feet (about 230 m) of the Palisades Sill. Drilling into the base of the quarry has penetrated another 200 feet (65 m) of Palisades; therefore about 78% of the total thickness of the Palisades sill is visible along the quarry walls. The upper contact is rarely exposed; however at Haverstraw a distinctly red hornfels is exposed. Some of the Lockatong hornfels has dropped down along normal faults to form a graben at the southern quarry wall. The northern end of the sill becomes increasingly dike-like and at Haverstraw dips to the south at about 15 degrees.
Some of the late to post-magmatic structures and textures that are exposed in the walls of the quarry include granophyres and pegmatoids. However, it is important to point out that these structures are confined to the upper Palisades. The geochemistry of the upper Palisades does not resemble the Orange Mountain basalt which is the principal objective of this chapter. The exception is the thin layer of upper chill zone that represents the upper portion of the first pulse of Palisades magma. All late pulses have intruded between the initial upper and lower chill zones. However, we have not yet analyzed samples of diabase from the upper chill zone at Haverstraw and it is possible that some late pulses intruded parallel to and above the initial chill zone, although evidence of hornfels layers or chill zone contained within the sill have not yet been found.
Granophyres
Ferrogranophyres are defined as rocks primarily composed of residual liquid with > 55% SiO2 and > 14% FeOT. In Fort Lee, NJ these constitute the sandwich horizon where the upper and lower crystallization fronts meet. The granophyre assemblages at this location exhibit significant deuteric alteration exemplified by pyroxenes almost entirely replaced by amphibole, sericitized plagioclase, and abundant myrmekite.
Gabbroids/Pegmatoids
In Upper Nyack, ferrogranophyres adopt a gabbroid/pegmatoid texture and occur from ∼ 200 m to ∼ 300 m. At 84 m where FeOT reaches a maximum of 18%, the texture corresponds to a coarse ferrodiorite with abundant skeletal opaques, large euhedral plagioclase, and interstitial pyroxene. Higher in the section, (124 m to180 m) the ferrodiabase exhibits a similar texture to that observed at 84 m. Hornblende often replaces pyroxene along the rims and is accompanied by alteration products of plagioclase (sericite). From 168 m to 250 m the most evolved differentiates are ferrogranophyres containing abundant interstitial myrmekite and opaques, and exhibiting evidence of hydrothermal alteration. There is evidence of sheared fabrics possibly caused by transport of residual liquid northward, and resulting in changes in the mineral assemblages near the solidus temperature.
At the Haverstraw quarry, smeared lenses of light-colored granophyric pegmatoid are apparent near the upper contact (Fig. 12). These lenses have been previously interpreted as products of segregation of liquid expelled from crystal mush accumulated on the floor of the magma chamber (Ragland and Arthur, 1985) and has been dubbed a ‘pocket pegmatite’ (Steiner et al. 1992). In places where pocket pegmatites occur, large crystals grow against the facies boundaries as a result of rapid crystal growth likely due to saturation with an deuteric fluids.
Zeolite veins
Most of the mineralized veins exposed in the wall of the Haverstraw occupy thin (0.25 to 2 cm) joints that cut through the diabase at an angle to the columnar joint system. These joints are commonly mineralized with calcite, stilbite, prehnite, chabizite, and other zeolites as mono-mineralic veins or mixtures. Where there has been displacement along joints the slickensides are typically coated with chlorite or amphiboles.