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NYSGA 2011
New York State Geological Association
83rd Annual Meeting
Field Trip Guidebook
Co-Hosted by
Central New York Association Of Professional Geologists
and
Syracuse University
Department of Earth Sciences
Edited by Nanette R. Nelson
Published by the
www.nysga.net
www.nysgaonline.org
ACKNOWLEDGEMENTS
Thanks to the volunteer efforts of CNYAPG members Paul Freyer - NYSGA 83rd Annual Meeting website design and updates, Sean Pepling and Todd Marsh - registration processing, and Lynette Mokry - Facebook and Twitter updates.
Thanks to Jeff Karson, Bonnie Andrews, Student Volunteers, and others at Syracuse University Department Of Earth Sciences, for time, facility and expertise in making the meeting arrangements and coordinating the Volunteers.
Thanks to Gerry Gould, NYSGA President 2011, for creating our 83rd Annual Field Meeting.
Special thanks to the trip leaders and their coauthors, without whom this meeting would not be possible.
And thanks to the staff at The Apple Store, Syracuse New York, for their assistance in editing this book.

A1: EFFECTS OF ADIRONDACK BASEMENT UPLIFT ON JOINTS AND FAULT DEVELOPMENT IN THE APPALACHIAN BASIN MARGIN, NEW YORK
Joshua D. Valentino
Department of Geosciences
Virginia Polytechnic Institute and State University,
Blacksburg, VA 24061
David W. Valentino
Alex P. O’Hara
Hannah Valentino
Department of Earth & Environmental Sciences
State University of New York at Oswego
Oswego, NY 13126
Introduction
Recent development of unconventional shale gas plays in the Appalachian Basin has drawn considerable attention to basement structures, and joints and fracture zones in the Paleozoic cover rocks (Figure 1), and nowhere is this more apparent than in the region of central Pennsylvania through western and central New York State (Engelder and Lash, 2009; Engelder, 2008; Jacobi, 2002; Jacobi and Fountain, 1996). Two ubiquitous joint sets occur throughout this region (J1 and J2 of Engelder), in addition to significant domains of fracture intensification related to faults (Jacobi, 2002). It was demonstrated that the regional joint sets are largely the result of hydrocarbon maturation fluid pressure under late Paleozoic Alleghanian orogenic stress (Lash and Engelder, 2009), however domains of fracture intensification have been linked to faults in the underlying crystalline basement (Jacobi and Fountain, 1996; Jacobi, 2002). Basement structure controlled the distribution and orientation of brittle faults in the overlying Paleozoic strata (Jacobi, 2002), and in some cases the displacement on basement faults had a substantial influence on patterns of Paleozoic sedimentation (Jacobi and Mitchell, 2002).
The direct observation of basement faults that had control on the distribution and subsequent deformation of Paleozoic cover is limited to the exposure of Proterozoic rocks of the Adirondack dome (i.e. Isachsen, 1975; Isachsen, 1981; Roden-Tice et al., 2000; Jacobi and Mitchel, 2002). Roden-Tice et al. (2000) and Jacobi and Mitchel (2002) suggested that the Adirondack dome uplifted in segments that were accommodated by faults related to the Iaptian rift. Jacobi and Mitchel (2002) also discovered that the distribution of the Ordovician strata was controlled by fault bounded structural blocks, demonstrating fault activity during that period. Roden-Tice et al. (2000) and Roden-Tice and Tice (2009) demonstrated that the Adirondack region underwent differential uplift with the formation of the dome, and was controlled by change in bulk compression direction and reactivation of faults. Through apatite fission track dating, Roden-Tice et al. (2000) constrained the age of the dome uplift to mid-Jurassic through the Cretaceous. Wallach and Rheault (2010) suggested that the gentle southwestern incline of the Ordovician strata west of the Adirondacks, to be directly the result of basement faulting and uplift of the Adirondack dome. They further suggested that reactivation of the Carthage-Colton shear zone and movement on the Black River fault contributed to the formation of the Tug Hill plateau. Earlier, Isachsen (1981) reported on Adirondack fault zones that form small graben that contain remnants of the Paleozoic strata that covered the Adirondacks prior to uplift. Additionally, Isachsen (1975; 1981) proposed that neotectonic activity continues in the Adirondacks, and this is partially supported by seismic activity on the Saint Lawrence fault zone and in the Champlain Valley (Barosh, 1986; 1990; 1992; Faure et al., 1996; Mareschal and Zhu, 1989; Wallach, 2002). A statistical correlation between faults and seismic activity led Deneshfar and Ben (2002) to conclude that northwest striking faults in the Adirondacks are more likely to exhibit seismic activity.
It is apparent that faulting in the Proterozoic basement of the Adirondack dome exhibits a protracted history, ranging from late Proterozoic through the Cretaceous, and possibly even neotectonic in nature. Although it was demonstrated that basement faults penetrate the Paleozoic rocks adjacent to the Adirondack dome, the extent of joint and fracture zone development associated with rise of the dome has yet to be described. The intent of this investigation was to address this issue though a detailed study of joints and fracture zones in the Middle Ordovician rocks that directly overly the western flank of the Adirondack dome. This is the region of the Tug Hill plateau, where Wallach and Reault (2010) recently identified basement faults that extend into the Paleozoic strata (Figure 2), and where deformation associated with the Appalachian basin (i.e. Jacobi, 2002; Engelder, 2009) is most likely overlapped by deformation related to the uplift of the Adirondack dome.

A1: EFFECTS OF ADIRONDACK BASEMENT UPLIFT ON JOINTS AND FAULT DEVELOPMENT IN THE APPALACHIAN BASIN MARGIN, NEW YORK

STOP 1. Lake Ontario at SUNY Oswego
The field trip begins at the parking-lot for Mary Walker Health Center on the campus of SUNY Oswego. From the parking-lot, follow the path along the lake shore toward the east to the first metal stair case. The outcrop of interest is at the bottom and to the west of the stair case.
A. Thick to medium bedded Oswego sandstone.
B. Two prominent joint sets (east-northeast and southeast striking).
C. Sinistral fault in the pavement outcrop.
D. Evidence for minor sinistral displacement on individual east-northeast striking joints.
E. East-northeast striking en-echelon fracture zones with sinistral geometry.

STOP 2. Lake Ontario in East Oswego
From the parking-lot, walk east along the lake shore to the first large exposure of the Oswego sandstone.
A. Thick bedded Oswego sandstone.
B. Two prominent joint sets (east-northeast and southeast striking)
C. Fracture zone about 1 meter wide.

STOP 3. Salmon River Falls
From the parking-lot, follow the trail northeast to the top of the falls, and then follow the trail back toward the parking-lot to the entrance to the gorge trail.
A. Oswego sandstone at the top of the falls.
B. Pulaski formation in the gorge.
C. Joints and fracture zones in the Oswego sandstone.
D. Fracture cleavage in the shale beds of the Pulaski formation.
E. Normal fault on the southeast side of the base of the falls.

STOP 4. Mooney Gulf.
From the parking area, follow the gravel road into the gulf. There are excellent exposures on the north side of the gulf. See Figure 8 for a detailed joint map of Mooney and Totman Gulfs.
A. Whetstone Gulf formation.
B. East-northeast and southeast striking joints are present.
C. Some joints can be traced 10’s of meters.

STOP 5. Robert Wehle State Park at Stony Point.
From the parking-lot, walk northwest to the lake shore. There are several trails to the lake shore, but the closest is located behind the tennis court. Once on the lake shore trail, follow it toward the northeast and see the topographic map inset for reference. It will be necessary to traverse down the steep embankment to reach lake level. See Figure 19 for details.
A. Trenton Group limestone.
B. Minor normal faults with mineralized fractures.
C. Fault with no apparent displacement. The fault merges with bedding.
D. Large rock-fall that was controlled by two prominent joint sets.
Azimuthal Electrical Resistivity for Joint Analysis
Azimuthal ER (AER) involves a Wenner survey around a single point to look for directional variation, which can be impacted by the direction of groundwater-filled joints. The direction of the lowest ER values should correlate with the direction of the most prominent joints (Taylor and Flemming, 1988). At Stony Point, the limestone bedrock is very close to the surface with thin soil. In an attempt to locate joint patterns away from the lake shore, six azimuthal electrical resistivity (ARE) surveys were conducted (Figures 21 and 22). Each AER survey was completed with an automated 24 node system with the azimuthal increment of 30 degrees.

STOP 6. Whetstone Gulf State Park.
Excellent exposures of Utica black shale occur in the bed of the creek that parallels the park road into the gulf. As well, the Whetstone Gulf formation is exposed in numerous high-walls that can be accessed along the road side farther up the gulf.
A. Utica black shale.
B. Whetstone gulf shale and siltstone beds.
C. Complex joint sets in the Utica formation (see text for details).
D. Follow the trail into the gulf to view the transition from Whetstone Gulf formation to Pulaski formation.
E. Follow the Rim Trail to the head of the gulf to view thick sandstone beds on the lower Pulaski formation.

A2: THE MARCELLUS SUBGROUP IN ITS TYPE AREA, FINGER LAKES AREA OF NEW YORK, AND BEYOND
Chuck Ver Straeten
New York State Museum/Geological Survey
3140 Cultural Education Center
Albany, NY 12230
Gordon Baird
Gary Lash
Dept. of Geosciences
SUNY-Fredonia
Fredonia, NY 14063
Carlton Brett
Geology Department
University of Cincinnati
Cincinnati, OH 45221-0013
Jeff Over
Department of Geological Sciences
SUNY-Geneseo,
Geneseo, NY 14454
Ceren Karaca
Teresa Jordan
Department of Earth and Atmospheric Sciences
Snee Hall, Cornell University
Randy Blood
EQT Production
625 Liberty Ave, Ste 1700
Pittsburgh, PA 15222
INTRODUCTION
br /br /The Marcellus “shale” was long one of the neglected “ugly ducklings” of New York stratigraphy that was known mainly for its black shale facies, the cephalopod-rich Cherry Valley Limestone, its potential as a source rock, and occasional interesting fossil finds like the famous Devonaster starfish trove found in upper Marcellus sandstones of the Hudson Valley. Generally, it was seldom the focus of much attention, however, during the last five years Marcellus strata have been the center of scientific and public attention, both as a regional symbol of economic opportunity and of controversy regarding exploitation of hydrocarbons.
The Marcellus in New York State is considered a subgroup of the Hamilton Group, which includes two different major lithofacies suites: the classic thin, black shale/dark gray mudstone succession, with minor carbonates developed in central to western New York; and the thick, coeval synorogenic siliciclastic succession of basinal to marine shoreface and terrestrial deposits in eastern New York. Beginning in underlying upper Onondaga strata, the succession represents two major (“third order”) sea level cycles, which were apparently deposited over a 2-4 million year period. Total Marcellus thickness across the state ranges from less than 7.5 meters in the west near Buffalo to over 580 m in the Hudson Valley region (Rickard, 1989).
Herein we assemble a broad set of perspectives and knowledge on the strata of the Marcellus subgroup in the northern Appalachian Basin. Owing to the complexity of this topic the reader will find the paper divided into four chapters, written by various co-authors, as well the road log and brief stop descriptions at the end.

A2: THE MARCELLUS SUBGROUP IN ITS TYPE AREA, FINGER LAKES AREA OF NEW YORK, AND BEYOND
C.VerStraeten, G.Baird, G.Lash, C.Brett, J.Over, C.Karaca, T.Jordan, R.Blood

STOP 1. Marcellus subgroup at Seneca Stone Quarry
(parking area on left, inside the gate) This large active quarry exposes Devonian strata of the Eifelian and lower Givetian, as well as minor folding and a thrust fault distinctly visible on the southern wall; the Onondaga Limestone is the primary production unit. In the lowest level the Lower Devonian Manlius and Oriskany formations floor the quarry. Four members of the Onondaga are recognized in respective upward succession: Edgecliff, Nedrow, Moorehouse, and Seneca. The Seneca Member is easily recognized on the quarry faces as it is bound by two distinct ash beds that weather and stain the walls orange. The lower ash is the Tioga B – Onondaga Indian Nations Ash, which marks the base of the Seneca; the Tioga F is used to recognize the base of the Marcellus subgroup (Figure RL-1A). The entire Bakoven member of the Union Springs Formation (Figure RL-1B) and the succeeding lower Oatka Creek Formation, consisting of the upward succeeding Hurley, Cherry Valley, East Berne, and Chittenango members (Figure RL-1C) can be clearly seen in the quarry benches and walls.
The Bakoven Member, approximately 4 m thick here, overlies dark gray biowackestones of the Seneca Member and represent deposition in the HST and FSST of the 1d/Eif-2 sequence. The Tioga F Ash, approximately 10 cm thick, defines the base of the Marcellus and Union Springs Formation. The lowest part of the Bakoven is dark gray muddy biowackestones and packstones that contain ostracodes, bivalves, pelmatozoa, and dacryoconarids. Seventy centimeters above the base of the Bakoven is a disconformity that preserves abundant fish material, including acanthodian spines, crassopterygian teeth, and placoderm plates, preserved in thin grainstones that are developed in decimeter-scale wide shallow channels. These channels may be analogs of younger, linear erosional furrows associated with a channeled disconformity surface within the lower part of the dark Levanna Shale Member in Erie County, New York (see:Baird et al., 1999; stop 6). Above this disconformity are finely laminate black shales and thin calcareous beds, where the carbonate material is dominated by Styliolina, other dacryoconarids, and thin brachiopods that sometimes form thin grainstones and packstones. The upper Bakoven contains nodular carbonates and laminated black shales.
The Oatka Creek Formation is comprised of four ascending members: Hurley, Cherry Valley, East Berne, and Chittenango. The base of the 1e/Eif-Giv sequence is the Hurley Member which consists of light-weathering very fossiliferous biopackstone-grainstone, characterized by the proetid trilobite Dechenella, which is amalgamated onto the base of the Cherry Valley Member to form a single ledge-forming carbonate approximately 50 cm thick. The Hurley – Cherry Valley contact is an irregular hardground surface. The Cherry Valley is brown weathering, fossiliferous biopackstone-grainstone, and is remarkable for numerous large, truncated orthicone nautiloids and Agoniatites vanuxemi exposed on a corrosion surface, that based on sedimentological evidence, must have been exposed on the Devonian sea floor. These strata record deposition during the TST.
Black styliolinid-rich shales of the East Berne Member overlie the Cherry Valley Member. Several brachiopod-rich horizons occur in the lower 50 cm, which represent the first appearance of the Hamilton fauna, characterized by diverse corals and brachiopods. The Halihan Hill Bed is a 20 cm thick gray calcareous mudstone that marks the appearance of a more diverse shelly fauna, including Mediospririfer, Ambocoelia, Athyris, Pseudoatrypa, and others, and delineates the base of the Chittenango Member. These strata fall within the late TST of the 1e/Eif-Giv sequence. Based on magnetic susceptibility, the Eifelian- Givetian boundary is placed at the Cherry Valley – East Berne contact. The lower Chittenango is composed of organic-rich black shale containing variably rich styliolinid- and brachiopod-bearing horizons. Three horizons of large – up to 1 m in diameter - calcareous concretions are developed between 3 and 5 m above the base. These concretions are apparently also developed in the lower Chittenango Member at the Oatka Creek type section in LeRoy, NY as well as in strata near Marcellus (Stop 3). The Chittenango represents deposition during the HST and FSST; the base of sequence If/Giv-1 will be examined at Stop 2.
C.VerStraeten, G.Baird, G.Lash, C.Brett, J.Over, C.Karaca, T.Jordan, R.Blood

LUNCH STOP: Cayuga Lake State Park
C.VerStraeten, G.Baird, G.Lash, C.Brett, J.Over, C.Karaca, T.Jordan, R.Blood

STOP 2. Lockwood Family dairy farm quarry, Half Acre/Oakwood
This small quarry exposes strata of the uppermost Oatka Creek Formation (Cardiff Member) and lowermost Skaneateles Formation (Mottville Sandstone Member; Figure RL-2).
Medium dark gray, burrowed silty mudstones of the Cardiff Member (Oatka Creek Formation) comprise the lower approximately 2.3 m of the section here. The Cardiff Member here is slightly calcareous, and poorly fossiliferous. Coiled and straight nautiloid cephalopods are part of the sparse fauna; the “hitch-hiking” bryozoan Reptaria stolonifera was found on one of these.
The dark gray mudstones of the Cardiff are overlain by buff-colored, calcareous very fine sandstones of the Mottville Member. In this area, basal Skaneateles strata are in a transition from sandstone- to limestone-dominated facies (coeval Mottville and Stafford members, respectively). Baird et al. (1999) used the term Stafford Member here. Closer examination in the lab indicate an apparent greater percent sand to calcite at this locality, so the term Mottville Member is better applied.
Relatively low in the Mottville Member here a thin, fossiliferous highly calcareous sandstone bed 3.2 m above the base of the section, termed the Mottville A bed (Figure RL-2), is characterized by very fine to lower fine sand-size grains, and benthic fossils including the brachiopods Cupularostrum, Emanuella and Devonochonetes, auloporid corals, and other fauna. The upper part of the Mottville Member here, including the Mottville B bed, is less fossiliferous; however, at least some parts of it are heavily bioturbated by the trace fossil Zoophycos which may, alternatively mark even shallower water conditions than the Mottville A bed below. The greater degree of Zoophycos churning of the Mottville B interval may actually indicate the shallowest water conditions, and mark the Ie/Eif-Giv - If /Giv-1 sequence boundary. Although all of the buff-colored, calcareous sand-rich strata have been assigned to the Skaneateles Member, technically all of the strata below the shallowest point in the Mottville are progradational strata that are a part of the Sequence Ie/Eif-Giv FSST and belong to the Oatka Creek Formation. See Baird et al. (1999) for more details of Mottville Member facies and correlations.

STOP 3. Marcellus subgroup
Along NY 175/NY 174 near Slate Hill Road, Marcellus, NY
This roadcut along the east side of NY Routes 174 and 175 at the northwestern base of Slate Hill exposes the lower black shales of the Oatka Creek Formation (Chittenango Member). Additional nearby sections, however, expose most of, or all, of the Marcellus in its type area, around Slate Hill (Figure RL-3). Hall (1839) did not name a specific type section, but it likely would have been placed at Slate Hill.
Cherty fossiliferous limestones of upper part of the Seneca Member (Onondaga Limestone) are visible in roadcuts on either side of the highway to the north. Intervening strata of the Union Springs Formation and lowest Oatka Creek Formation (including the Hurley, Cherry Valley and East Berne members and the Halihan Hill Bed) are covered southward along the highway to Slate Hill Road.
However, the top Seneca, entire Union Springs through basal East Berne succession, and during some years the Halihan Hill Bed, is exposed in a nearby creek bed, approximately 500 m (0.3 miles) east of the intersection of Slate Hill Road and NY 174-175. The Onondaga-Marcellus contact is sharp here, with no K-bentonite bed at the contact. Topmost beds of the Seneca Member are overlain by 3.1 meters of Bakoven Member black shales with styliolinid to bedded/concretionary diagenetic limestones; the shale/limestone ratio approximates 3:1. These Union Springs strata are capped by a 70 cm-thick ledge of the Hurley and Cherry Valley limestones. Only one 12 cm-thick bed of the Hurley Member is recognized along the stream. Several centimeters of the overlying East Berne black shales were recently observed above the Cherry Valley ledge, and in earlier years the Halihan Hill Bed was also visible along the creek.
Beginning in the ditch near the intersection with Slate Hill Road is an extensive exposure of black, rusty-weathering pyritic fissile shale with multiple levels of small-to-large discoidal septarian concretions. The base of this succession in the lower Chittenango Member is likely close to the top of the Cherry Valley Member and the overlying Halihan Hill Bed. The cut continues to exhibit the same lithology up through the section, exposed southward along NY 174-175 for several 100 meters.
Much of the rest of the Oatka Creek Formation can be studied along a small gully that ascends the northwest side of Slate Hill, beginning at a culvert toward the south end of the roadcut. The section, most of which is exposed in and along the creek bed, rises approximately 40 meters (130 feet) above the road level. The upper part of the succession transitions into dark gray mudstones (Cardiff Member) in the vicinity of a large bend in the creek roughly 23 m in elevation above the road, but the top-Cardiff contact with the overlying Mottville Member is not reached in this locality. The Mottville Member forms the cap of a steep cascade near the top of a deep gorge – “Jacknife Ravine” - approximately 1 km (0.7 miles) to the southeast of the roadcut. This ravine has yet to be fully explored and has potential to yield the most complete Marcellus section in the area.

STOP 4. Upper Onondaga Formation and lower Marcellus subgroup
At Hanson-Jamesville Quarry
Outcrops at the far southeast end of the Hanson Aggregates quarry at Jamesville expose the Onondaga Limestone and the lower part of the Marcellus subgroup. Key features at this site include a thinner Seneca Member at the top of the Onondaga Formation, a prominent bone bed just above the Onondaga Marcellus contact, and black shales of the Bakoven Member (Union Springs Formation).
Between the Seneca Stone and Jamesville quarries (Stops 1 and 4), the Seneca Member thins from 7.1 m to 5.4 m. Regional correlation of the Tioga A-G K-bentonites indicate that while the Tioga F bed lies at the Onondaga-Marcellus contact at Stop 1, both the Tioga E and F beds are missing from the section. A 5-8 cm-thick bed below the topmost Onondaga Limestone bed is the Tioga D bed. The eastward thinning and top-down absence of Tioga K-bentonites and upper Onondaga strata continues to the Albany area (Seneca Member = 3.2 m at Oriskany Falls; 2.0 m at Cherry Valley; and zero in the Helderbergs). This is indicative of diachronous east to west tectonic-load induced subsidence of proximal areas of the foreland basin during the renewed onset of orogenesis in the Acadian mountain belt.
Given the absence of the Tioga F Ash at Jamesville, the Onondaga-Marcellus contact is placed at the highest Onondaga-like limestone (32 cm thick, above the Tioga D Ash bed). The contact is overlain by a 0-5 cm-thick lag bed rich in phosphatic debris with numerous fish bone fragments and teeth. This bed marks a prominent sediment-starved surface, associated with the end of carbonate production and transport in this region, and the concentration of resistant phosphatic lag material on the sea floor.
The sharp upper surface of the bone bed is overlain by black shales of the Bakoven Member of the Union Springs Formation. Only the lower part of the Bakoven is exposed much here. At times in the past, the top of the Cherry Valley Member could be found in the weeds at the south end of the black shale exposure, 6.5 m above the top of the Onondaga Limestone.
In a nearby creek exposure on private land (south of NY 173 and east of Sweet Road), the Onondaga- Marcellus contact, and approximately 1.3 m of lower Bakoven Member black shales, are succeeded by shales interbedded with thin packages of limestone, followed, in turn, by a covered interval. Upper Bakoven strata are again visible in the stream still farther upsection, where black shales and concretionary to thin-bedded limestones appear to be difficult to correlate between separate stream forks.
In the upper part of this creek section, the prominent Hurley-Cherry Valley limestones ledge (10 and 73 cm-thick, respectively) is capped by black shales of the East Berne Member. The Halihan Hill Bed is found at the top of the creek exposure, 73 cm above the top of the Cherry Valley. Here it is comprised of two distinct layers, a lower 13 cm-thick dacryoconarid-rich bed, and an upper 16 cm-thick layer with brachiopods and other normal marine benthic fauna, indicative of well-oxygenated conditions on the sea floor at that time. The base of the Hurley Member and the base of the brachiopod-rich upper Halihan Hill Bed mark the base of two of three fourth order sequences within the Oatka Creek Formation (Sequence Ie/ Eif-Giv).
A near by abandoned quarry, also on private land, exposes a thick succession of mid (?) to upper Oatka Creek dark gray mudrock facies, mostly corresponding to the Cardiff Member interval. The Mottville Sandstone, the basal member of the Skaneateles Formation, is not seen in the quarry.

A3: THE GREEN VEDDER MEMBER – A HIGHSTAND SYSTEMS TRACT IN THE “PERITIDAL” MANLIUS FORMATION
Randall Wilson, James Ebert and Damon Matteson
Department of Earth and Atmospheric Sciences
SUNY College at Oneonta
Oneonta, New York 13820-4015
INTRODUCTION
Since the stratigraphic synthesis of Rickard (1962) and the sedimentologic interpretations of Laporte (1967, 1969), the Manlius Formation of the Helderberg Group has attained iconic status representing peritidal environments in the overall transgression of the Helderberg Sea. Although Laporte (1969) described Manlius facies that recorded subtidal conditions (e.g., stromatoporoid biostromes), most workers think of the Manlius as dominated by facies that represent supratidal and intertidal environments. The Manlius actually displays much greater variability of facies than is commonly thought. On this field trip, we will explore the Green Vedder Member of the Manlius Formation (Ebert and Matteson 2003a, b), a distinctive and traceable stratigraphic unit that records highstand (subtidal) conditions within the Manlius Formation. This Manlius highstand occurred well before the New Scotland highstand that is regarded as the transgressive maximum in the lower Helderberg sequence. Recognition of the Green Vedder highstand has also provided important biostratigraphic information with respect to the location of the Silurian/Devonian boundary (Matteson and Ebert 2011) in the Appalachian Standard Succession of New York State (Johnson and Murphy 1969).

A3: THE GREEN VEDDER MEMBER – A HIGHSTAND SYSTEMS TRACT IN THE “PERITIDAL” MANLIUS FORMATION

STOP 1. Road Cut on Sprout Brook Road
The following stop description is modified from the description of Stop 1 of Ebert and Matteson (2003b) and Stop 1a by Ebert and Matteson in Ver Straeten et al. (2005). STOP 1 is the stratigraphically lowest of a series of outcrops on Sprout Brook Road (Cty. Rt. 32), Rt. 166 and U.S. Rt. 20 that expose the upper Silurian (Ebert and Matteson 2003a, b) and much of the Lower Devonian section that is present in New York State (See Brett and Ver Straeten 1997). This outcrop corresponds approximately to Rickard’s (1962) section 94, which was measured in nearby Judd’s Falls.
The section begins at the north end of the outcrop with approximately one meter of the Rondout Formation (Přídolían). The Rondout is abruptly overlain (Mine Lot Falls Unconformity of Ebert 2008) by the Thacher Member of the Manlius Formation (11.2 m thick). A distinctive zone of thrombolitic mounds occurs two meters above the Mine Lot Falls Unconformity. Regional tracing of the thrombolitic zone shows it descending westward relative to the Mine Lot Falls Unconformity (westward onlap of the Thacher Member) and rising stratigraphically eastward (Ebert 2008). This thrombolitic marker zone is also present at STOPS 3 and 4 on this trip and is important in recognizing the Thacher Member where it is thinned by truncation and onlap.
Less than one meter below the top of the Manlius Formation, the Clockville Unconformity (Ebert and Matteson 2003a, b) marks an abrupt change in the style of bedding to thinner (decimeter scale) limestone beds with interbedded dark gray to black shale (Fig. 19). These beds (total thickness = 0.82 m) comprise a thinned portion of the Green Vedder Member. The dark shale interbeds of the Green Vedder Member contain a distinctive carbonized biota comprising scolecodonts, annelid bodies, and non-calcified green algae (Medusaegraptus) (Matteson, Natel and Ebert 1996). The faunal content and general lithology of this thin remnant of the Green Vedder Member are strikingly similar to upper portions of the member from thicker sections to the west (e.g., Oriskany Falls) and to the east (I-88, Schoharie Valley). This similarity suggests onlap of the Green Vedder Member onto a paleo-topographic high in the Cherry Valley area and that the Clockville Unconformity is more pronounced here than at sections that record greater subsidence to the west and east.
The Green Vedder beds are cut by a sharp surface which is the Terrace Mountain Unconformity (13.27 m from base of section) (Ebert, Matteson and Natel 2001; Ebert and Matteson 2003a, b). The Dayville Member of the Coeymans Formation rests on this unconformity. The Dayville is comprised of coarse echinoderm grainstones and packstones, interbedded with mudstones and skeletal wackestones. Total thickness of the Dayville here is 4.03 meters (corrected from Ebert and Matteson 2003). The overlying Ravena Member of the Coeymans Formation is separated from the Dayville Member by the Howe Cave Unconformity (Ebert, Matteson and Natel 2001; Ebert and Matteson 2003a, b).
Combined, the Green Vedder beds and the Dayville Member appear to constitute a gradational transition (Grabau’s [1906] “transition beds”) between the Manlius and Coeymans formations, a key factor in Rickard’s (1962) stratigraphic reconstruction. However, such a gradation does not exist owing to the presence of the Clockville Unconformity and the Howe Cave Unconformity, which bound the interval and the Terrace Mountain Unconformity, which occurs within it. The Green Vedder Member and Dayville Member are traceable across the northern portion of the outcrop belt of the Helderberg Group. These members are distinctive and do not comprise an ambiguous zone of transition.

STOP 2. Green Vedder Road
Type Section of the Green Vedder Member, Manlius Formation
Stop 2 (associated with R-131 of Rickard 1962), which is located on Green Vedder Road on the edge of the large active quarry near Oriskany Falls, comprises the type section of the Green Vedder Member of the Manlius Formation. The member reaches its greatest thickness (5.6 m) here. The lower contact (Clockville Unconformity) with the underlying Thacher Member is exposed near the base of the outcrop at the southern end of the exposure. The Terrace Mountain Unconformity marks the top of the Green Vedder Member and separates it from the overlying skeletal-rich, stromatoporoid-bearing packstones to grainstones of the Dayville Member (previously mapped here as Olney Member by Rickard [1962]).
The Green Vedder Member comprises decimeter-scale beds of skeletal/peloidal packstones and wackestones interbedded with gray, calcareous shales. The carbonate beds in the Green Vedder display broad hummocks (1 m; Fig. 20) that are much greater in wavelength than equivalent strata to the east (e.g., I-88 near Schoharie).
We interpret the carbonate beds of the Green Vedder as tempestites that record episodic storms in the Helderberg Sea. Greater thicknesses of shaly interbeds and longer hummock wavelengths suggest that the Green Vedder at its type section represents deeper conditions than those that existed to the east. Some carbonate beds display Thalassinoides and Planolites burrows. These are particularly well developed on the base of the thick middle bed (TMB). Abundant Garwoodia (codiacean alga) occur approximately 20 centimeters below the top of the member. Skeletal debris of pelagic scyphocrinitid crinoids are abundant in the carbonate beds and a partial lobolith (Camarocrinus) is exposed on the bedding plane (Fig. 16) across the road from the main outcrop.
Shaly interbeds in the Green Vedder type section exhibit the carbonized biota that is so distinctive of this member (Matteson, Natel and Ebert 1996). Chondrites burrows are common in the shaly beds and a pyritized microbial mat (Fig. 12) was collected here from one of the shaly interbeds.

STOP 3. Clockville Road Cut
Approximately four meters of the Chrysler Member of the Rondout Formation are exposed in this large road cut (Section 142 of Rickard 1962). The contact with the overlying Thacher Member of the Manlius Formation is the Mine Lot Falls Unconformity, a sharp surface upon which thrombolitic mounds have nucleated. We regard this massive, thrombolitic bed (0.9-2.0 m thick) as the total thickness of the Thacher Member at this location.
The top of the Thacher Member displays up to 20 cm of erosional relief along the Clockville Unconformity (Fig. 3). This surface is overlain by a coarse, cross-stratified skeletal grainstone that is semicontinuous across the outcrop. Lithoclasts of Thacher lithologies are incorporated in this grainstone. The lithology and texture of this bed is atypical for both the Thacher and Green Vedder members of the Manlius Formation. Where the coarse bed is discontinuous, it is preserved locally in scoured pockets along Clockville Unconformity.
Approximately four meters of the Green Vedder Member rest on the Clockville Unconformity. The cm- to dm-scale beds of the Green Vedder contrast sharply with the massive Thacher below (Fig. 17). In several places along the outcrop, the lowest beds of the Green Vedder lap onto local high spots along the Clockville Unconformity (Fig. 21). Shaly interbeds in the Green Vedder contain the member’s signature carbonized biota. The TMB is well-displayed in the Clockville road cut. Carbonate beds in the upper portions of the Green Vedder are noticeably thicker than in the lower half of the member. These beds also tend to be richer in skeletal debris than beds in the lower half. Thinner beds reappear in the uppermost 1.5 m of the member.
The Terrace Mountain Unconformity separates the Green Vedder Member from the superjacent Olney Member of the Manlius Formation. Here, the lowest Olney is a massive stromatoporoid biostrome.

STOP 4. Split Rock Quarry
Rickard (R-156; 1962, p. 54 and 149) described the section exposed at Split Rock Quarry as "33 feet of fine-grained, even bedded limestones" of the Olney Member, overlain by 3 feet of Elmwood waterlimes. Rickard did not recognize any Thacher Member at this location. Rickard’s “Olney” rests upon a sharp contact (Smith 1929; Logie 1933) with the underlying Rondout Formation, which is exposed in the floor of the quarry (Fig. 22). This sharp contact is the Mine Lot Falls Unconformity of Ebert (2008). In the northeastern section of the quarry, an additional 1.3 m of the Rondout, comprising dolomitic mudstones with abundant domal stromatoporoids are exposed below the Mine Lot Falls Unconformity. In this area, approximately 30 cm of the thrombolitic marker bed within the Thacher Member rests on the unconformity (Fig. 23). Above the thrombolitic horizon, an additional ∼2.9 m of the Thacher Member are exposed. Here, the Thacher displays mudstones and skeletal wackestones that alternate with very fine grained dolomitic grainstones. Planar to wavy or lenticular beds, with laterally discontinuous and rippled laminae are common in this section of the Thacher.
The Clockville Unconformity separates the Thacher Member from approximately 30 cm of the Green Vedder Member, which is exposed in the western section of the quarry. The Green Vedder comprises thin to medium-bedded skeletal wackestones to packstones with dark shale interbeds containing Medusaegraptus, a representative of the distinctive biota that occurs in the Green Vedder throughout central New York. Fauna in the limestones includes H. vanuxemi, M. varistriata, ostracods, crinoid and trilobite debris, and rare pelecypods.
The Terrace Mountain Unconformity separates the Green Vedder from ∼6.4 m of the Olney Member of the Manlius Formation. The Olney is a hard, grey, dolomitic skeletal limestone, which ranges from laminated to massively bedded. The sedimentology and ichnology of the Olney are described by Wilson (2010). Numerous sedimentologic and ichnologic features in the Olney indicate deposition under arid to semi-arid, evaporative supratidal (sabkha) to high intertidal conditions.

A4: QUARTZ-SILLIMANITE VEINS AND NODULES IN LYON MOUNTAIN GRANITE, AND THE OCCURRENCE OF PRISMATINE IN METAPELITIC GNEISS AND QUARTZITE, MOOSE RIVER, WESTERN ADIRONDACKS
James McLelland
Department Geology
Colgate University
Hamilton, NY, 13346
Robert Darling
Department of Geology
SUNY, College at Cortland
Cortland, New York, 13045
INTRODUCTION
The western Adirondacks contain a wide variety of rock types, and this trip will visit representatives of the major lithologies. Stops include units of Lyon Mountain granite recently dated by U-Pb geochronology including multi- and single-grain TIMS and SHRIMP II analyses as well as in-situ dating of monazites.
The Adirondack Mountains represent a southeastern extension of the Grenville Province via the Thousand Islands – Frontenac Arch across the St. Lawrence River (Fig. 1). The region is topographically divided into the Adirondack Highlands and Lowlands separated by the Carthage-Colton Mylonite Zone (CCMZ, Fig. 2). The former is underlain largely by orthogneiss metamorphosed to granulite facies and the latter by upper amphibolite facies metasediments, notably marbles and calcsilicate. Both sectors have experienced multiple deformations resulting in refolded major isoclines. The intrusion history is summarized by a tripartite division, as summarized below and in Fig. 3. Broadly, the plutonic lithologies fall into the following five groups: 1350-1300 Ma tonalites rifted from Laurentia at ca. 1300 Ma.; 1250 Ma granodiorites; 1160-1150 Ma anorthosite-mangerite-charnockite-granites (AMCG suite); 1100-1090 Ma Hawkeye granite; and 1055-1040 Ma Lyon Mountain Granite (LMG). The four major orogenic events associated with these are: an Andean-type arc along southeast Laurentia, the Elzevirian (ca1250-1220), the Shawinigan (1210-1140 Ma), the Ottawan (1090-1030 Ma), and the Rigolet (1000-980 Ma) orogenies (Fig. 3). The Elzevirian involved a back-arc rift basin with protracted outboard arc magmatism and accretion and was followed by the Shawinigan Orogeny due to the collision between Laurentia and the Adirondack Highlands – Green Mountain Terrane. The Ottawan was a Himalayan-type collision of Laurentia with Amazonia (?). Most of the metamorphic and structural effects present in the Adirondacks are the result of the Ottawan Orogeny, but Shawinigan and Elzevirian features can be recognized where minimally overprinted by the Ottawan. Both the AMCG suite and the LMG are thought to be late- to post-tectonic manifestations of delamination of over-thickened orogens undergoing terminal extensional collapse.
Structurally, the central and western Adirondack Highlands are dominated by the same large, recumbent fold-nappe structures (F2) as found in the southern Adirondacks (Fig. 2), and with fold axes oriented dominantly ∼NE-SW and ∼E-W parallel to stretching lineation. As in the southern Adirondacks, these Ottawan fold-nappes are thought to possess sheared-out lower limbs, but this has yet to be demonstrated at map scale. F1 folds of Shawinigan age occur as minor folds within the much larger F2 recumbent isoclines. At least two distinguishable upright fold events are superimposed on the nappes: F3 with shallow plunging ∼E-W axes and F4 with shallow-plunging NNE axes. Both of these can be shown to be of late Ottawan (ca, 1050-1040 Ma) origin. All of three fold sets affect Hawkeye and older units, and thus must be of Ottawan age. This is also the case with the strongly penetrative rock fabric, including strong ribbon lineations that are present in these rocks and are largely associated with the large fold-nappes. Intense fabric and nappe structure are largely absent from the ca. 1050 Ma LMG; however, this unit is folded by F3 and F4, and this is interpreted to reflect its intrusion in late, post-nappe stages of the Ottawan orogenic phase of the Grenvillian orogeny. In the northern portion of the eastern Adirondacks the NNE, F4, folds become quite tight and have a strong lineation associated with them. This may be the result of rock sequences being squeezed between large, domical prongs of anorthosite during terminal Ottawan exhumation.
Most of the region likely experienced peak Ottawan temperatures of ∼750-850o C and pressures of ∼5-8 Kbar (Kitchen and Valley, 1995, Florence et al, 1995, Spear and Markussen, 1997; Storm and Spear, 2005 and Darling et al., 2004). Evidence exists that similar P, T conditions were attained in the Shawinigan orogeny (Heumann et al., 2006). Based upon extensive oxygen isotopic work by John Valley and his students, it appears most likely that Ottawan metamorphism proceeded under fluid-absent conditions (Valley and O’Neil, 1982, Valley et al., 1990). Note, however, that this does not exclude the presence of late, post-peak fluids associated with the emplacement of Lyon Mountain granite.
The most recognizable fold patterns in the Adirondack Highlands are those of the ∼E-W F3 and ∼NNE F4 folds that span the entire region, e.g., Fig. 2, P (Piseco dome). These upright, relatively open folds exhibit E-W stretching lineations coaxial with the F3 folds. Because both these fold sets affect the ca. 1050 Lyon Mt. Granite and are crosscut by it, they are most likely synchronous with the terminal, extensional phase of the Ottawan orogeny. We interpret them as “a” and “b” domical folds that have been identified in large scale extensional orogens such as the Aegean core complex (Jolivet et al., 2004) and are due to the extension itself. Axes of the “a” folds form parallel to the principle extension due to constriction, whereas the “b” folds form approximately perpendicular to extension and slightly postdate the “a” folds. The axes of F2 folds are approximately parallel to extension and may have formed in this orientation and/or were rotated into it by extensional strain.
Recent investigations in the Grenville Province demonstrate that the Ottawan orogen (Rivers, 2008) and its Adirondack outlier (McLelland et al., 2010a) underwent terminal extensional collapse that, in the latter case, was accompanied by emplacement of LMG. The most complete local study of this sort is that of Selleck et al. (2005) that utilized zircon geochronology to document that down-to-the-west displacement along the northwest dipping Carthage-Colton Shear Zone (CCZ, Fig. 2) was coeval with intrusion of Lyon Mt. Granite (Fig. 2) into the fault complex at ca 1050-1045 Ma. It is thought that, at peak Ottawan contraction, the over-thickened lithosphere experienced delamination by foundering, convective thermal erosion, or both. Following delamination of the dense lithospheric keel, the orogen rebounded and hot asthenosphere moved to the crust-mantle interface where it underwent depressurization melting to yield aluminous gabbro that differentiated into anorthositic crystal mushes that ascended, along with crustal granitic melts, to yield the ca. 1050 Ma AMCG suite that is exposed in Canada (Fig. 2) as the Lac Allard massif and the Labrieville to St. Urbain CRUML belt (Owens et al., 1994, Morrisett et al., 2010, McLelland, 2010b). The asthenospheric diapir likely underwent degassing, and caused fertilization and melting of deep crust to yield A-type LMG. As the granite ascended into the crust, it both lubricated and enhanced low-angle normal faults formed in response to increased topographic elevation, fluids, and anatexis; all leading to orogen collapse. In such situations, it is not uncommon to find that collapse is quasi-symmetrical around the orogen core thus giving rise to a mega-gneiss dome or double-sided core complex such as the Shuswap complex (McLelland 2010a, Wong et al, 2011).

A4: QUARTZ-SILLIMANITE VEINS AND NODULES IN LYON MOUNTAIN GRANITE, AND THE OCCURRENCE OF PRISMATINE IN METAPELITIC GNEISS AND QUARTZITE, MOOSE RIVER, WESTERN ADIRONDACKS

STOP 1. Lyonsdale Bridge (45 Minutes)
River-washed exposures begin at the bridge over the Moose River that adjoins the Burroughs Paper plant at Lyonsdale. A coarse, steeply east-dipping pegmatite can be seen descending down a steep cliff face and crossing the river onto the exposures immediately beneath the bridge. The pegmatite is zoned with a quartz core containing sillimanite and magnetite. McLelland et al., (2001) report a single grain TIMS upper intercept age of 1035 ± 10 Ma for the pegmatite (McLelland et al., 2002). A nearby sample of LMG yielded a SHRIMP and single grain TIMS age of 1046 ± 4.4 Ma (McLelland et al., 2001). The pegmatite age appears to be ∼10 Ma too young and redating by SHRIMP would be very desirable. Nonetheless, it overlaps with the average LMG (n = 11) age of 1049 ± 10 Ma ( McLelland and Selleck, 2011).
LMG consists of pink equigranular quartz and feldspar with small amounts of magnetite and occasional biotite. It shows virtually no penetrative grain shape fabric (Fig. 7b) and, despite examples of tight folding in the outcrop, appears to be undeformed by the nappe-like folding that affects all rocks older than 1050 Ma and imparts to them pronounced ribbon lineation and grain shape fabric. In contrast, LMG displays a good igneous texture resembling that of hypersolvus granite. Elsewhere it has been shown that late, upright folds trending E-W and NNE-SSW fold some LMG and were formed during the ca. 1050 Ma extensional collapse of the Ottawan orogen (McLelland et al., 2010). We are confident that the tight, disrupted, isoclines defined by quartz and granitic veins in the riverbed are the result of flow folding due to LMG magma emplacement (McLelland et al., 2002a,b).
As shown in Fig. 6, LMG has been penetrated by myriad white veins that consist of sillimanite and quartz with subordinate magnetite (Fig. 7a). There are several distinct generations of these, and it is clear that some groups are more deformed than others (Fig. 8a). The dominant, and perhaps youngest, trend is N50E. Careful examination of quartz nodules will show that they commonly form linear trends that are best explained by disruption or boudinage.
Where LMG intruded country rock, the former contains garnet. The original country rock was a calcsilicate but has been contaminated by the granite and its fluids. It is common to find aligned boudins of this rock in the stream bed. They tend to be angular and separated by granite and most likely represent blocks disrupted by the magma. Other important features to be seen are pegmatites that transition from two feldspar to albite rich and even to quartz veins with magnetite. At one place a sillimanite-magnetite veinlet can be recognized when sunlight hits it in a certain direction. The same is true with several occurrences of very coarse (∼6”) sillimanite.

STOP 2. Agers Falls (45 Minutes)
This stop exposes riverbed outcrops of LMG immediately southwest of a small hydroelectric facility on the Moose River. Fig. 8 presents some of the important relationships at Ager’s Falls. Fig. 8A shows the same multiple, cross-cutting vein sets as seen at Lyonsdale Bridge. Note how the older set has been disrupted into nodules. In Fig 8B trains of nodules are shown crosscutting dark, xenolithic fragments of country rock calcsilicate. A similar scenario is shown in Fig. 8F that also contains late pegmatite veins. The crosscutting of the calcsilicate xenoliths is a critical relationship, because it establishes the post-intrusion origin of the quartz-sillimanite veins and nodules, i.e., they are not due to incorporation of “aluminous quartzite “into the magma. In Fig 8C several vein sets can be seen with the one pointed to by the pen clearly undergoing ductile boudinage consistent with extension in a fairly viscous magma. A very late, thin vein wanders across the field parallel to the pen. Figs. 8D and Fig 8G display a crucially important exposure in which a pegmatite-cored granite dike crosscuts, and ductilely deforms, the quartz-sillimanite vein-nodule system in a sinistral shear zone. The granite in the dike is good LMG identical to that in the country rock, but it contains no veins or nodules. This informs us that LMG magma was still present when the veins and nodules were being formed as a viscous magma was being fractured by rapid strain rate forces associated with emplacement into a fault controlled magma chamber. The granite then evolved a pegmatitic core as the magmatic episode drew to a close. It is likely that these processes were taking place near the top of the pluton, perhaps in a cupola. A self-consistent sequence of events is shown in Fig. 9 where a sheet of magma in a N50E shear zone has plucked off xenoliths parallel to its margins. As fluid pressure built in the crystallizing magma, movement along the shear zone triggered extensional fracturing parallel to sigma-1 and filled with hot, acidic magmatic fluids giving rise to quartz-sillimanite veins via hydrolysis. Sinistral shearing continued into frame 9C and resulted in rotation and boudinage of the earlier veins. By frame 9D, fluid pressure had built up again and a new set of extension fractures were produced along with subsequent rotation, boudinage, etc. In this way, the crosscutting vein system evolved with earlier veins getting rotated and boudinaged into nodules (McLelland et al., 2002 a, b).
There are places in the Ager’s Falls exposures where tight isoclinal folds defined by quartz veins are present, However these are disharmonic and the veins are discontinuous. The best explanation for these folds is that they are the result of flow-rate variations in a magma.
As the Moose River is followed farther downstream, the quantity of quartz veins increases until the rocks pass into a thick, sillimanite-bearing megaquartz vein complex that we will visit at Stops 3, 4, and 5. The quartzite is clearly of hydrothermal origin, and we interpret it to represent the release of late magmatic fluids through the carapace of a large LMG pluton.

STOP 3. Quartz Vein Complex at Fishing Access Site
These stream exposures contain quartz veins, pegmatite veins, and veins of granite. The green and red coloration of portions of the rocks is the result of hydrothermal fluids acting on iron oxides and iron bearing silicates. The wide expanse of quartz is due to widening of the vein system visited at the end of stop 2. The quartzite is interpreted as the end product of leaching of alkalis from the original granite leaving a residue rich in silica and alumina. Magnetite, hematite, and later chlorite result in the pink to green coloration in the rock.

STOP 4. Quartz-Sillimanite Rock & Illite-Diaspore, Kosterville Dam
Exposures at the base of the dam display ∼100 feet wide coarse grained, massive, sillimanite-bearing quartzite discussed by Selleck et al., 2004). Broken-off fragments show randomly oriented sillimanite crystals up to 6” long. Scattered across the outcrops of quartzite are large (up to 20 cm.), porcellanous, and irregularly shaped salmon- and green-colored platelets consisting of diaspore and illite. It is common for these minerals to pseudomorph sillimanite. These features are interpreted as low T (200°C) alteration features related to later hydrothermal alteration that dissolved and redistributed silica and alumina as fluids permeated the fracture network. Fluid inclusion work indicates oxidizing and highly saline (20% NaCl) fluids. Interestingly, the illite-diaspore platelets contain high concentrations of altered zircon that we interpret to be the consequence of leaching of labile constituents (e.g., alkalis) from the original granite leaving a residue rich in quartz, alumina, and zircon. A few viable zircons yield ages of ca. 1030-1050 Ma. Although the quartzite is poorly layered, there does appear to be a gently dipping tectonic foliation defined, in part, by the illite-diaspore platelets.

STOP 5. Shibley Bridge Complex
These interesting exposures are a continuation of the mega-quartz vein occurrence seen at the last three stops. The border with the granite is visible near the west end of the waterfall. Beneath Shibley Bridge there occurs a rock consisting of what looks like a quartz boulder conglomerate. However, close inspection will prove it to be the megaquartzite that has been deformed in such a manner to produce boulder-size rounded boudins of coarsely crystalline quartz in finer, grain-size reduced quartz that superficially resembles a sedimentary conglomerate.
At the waterfall, staining of the rock with sodium cobaltinitrite reveals the presence of a fine grained, potassic phase that takes the yellow stain and clear quartz grains that do not. Thin sections reveal that the potassic phases consist of muscovite and K-feldspar that were deposited by fluids in fractures that have rendered the quartzite a mass of sand grain-size fragments. Directly above the waterfall, a dark, red-stained band heads in the direction of the road, Careful sampling reveals that it consists of very coarse sillimanite inter-grown with magnetite. This assemblage was a principal iron ore at Benson Mines and, given its composition, must be hydrothermal.

STOP 6. Prismatine-Bearing Gneisses
Follow the all-terrain vehicle path downstream for about 200 meters. The path passes through the stone foundations of the former Moose River tannery and then follows rapids as the Moose River heads southwest. Here, the river cuts through northwest-dipping, calc-silicate gneisses and quartzites. Stay high on the river bank until the rapids disappear. The path will descend and cross a small, wet, muddy creek bed. Afterwards, the Moose River pools and turns north and the first outcrops on the west side of the river are the prismatine-bearing rocks. Please exercise caution while walking among the river boulders and talus at the base of the outcrops. Also, please DO NOT USE HAMMERS at this stop and refrain from collecting prismatine specimens unless you’re planning to study them scientifically; a future geologist will be grateful someday.
The feature of geologic interest at STOP 6 is the exceptionally well-developed prismatine crystals in coarse-grained, feldspathic lenses. Here, prismatine crystals form dark greenish-black, euhedral, elongated grains (up to 10 cm in length) that commonly display radiating patterns in feldspathic lenses one to three cm thick (Figure 11A). The prismatine crystals appear to have grown only within the plane of the foliation. However, upon closer examination, the prismatine grains are seen to be arranged randomly, but the longest and best-developed crystals formed parallel to the foliation plane. Because of this, Darling et al. (2004) inferred that non-deviatoric pressure conditions prevailed locally during prismatine formation. It should also be noted that a number of prismatine-bearing feldspathic lenses are located adjacent to fine grained tourmaline + plagioclase + biotite–rich zones near the north end of the exposed rocks. In these locations, the prismatine-bearing feldspathic lenses texturally embay, cross-cut earlier foliation, and appear to form at the expense of the tourmaline-bearing zones (Figure 11B). The embayed country rocks, coarser grain size, and the random arrangement of the prismatine crystals led Darling et al. (2004) to interpret the feldspathic lenses and the prismatine found in them to be of anatectic origin.
Plagioclase, K-feldspar, minor quartz and rutile are the most common phases associated with prismatine, but biotite, cordierite, garnet and rarely sillimanite occur locally as well. The prismatine contains 0.73 to 0.79 formula units of B (out of 1.0) and has Mg / Mg + Fe between 0.70 and 0.73 (Table 3 of Darling et al., 2004). After determining the associated mineral compositions, Darling et al. (2004) proposed the following prismatine-forming reaction:
Tourmaline + sillimanite + biotite + cordierite → prismatine + rutile + melt (1).
This reaction is similar to a number of proposed prismatine-forming reactions from other granulite terranes (Grew, 1996), including those in sapphirine-free rocks found in the Reading Prong, New Jersey (Young, 1995), and in Waldheim, Germany (Grew, 1989). In those cases, garnet rather than cordierite was a proposed reactant.
Metamorphic temperatures and pressures are difficult to estimate from prismatine-bearing mineral assemblages as little is known about the stability of boron-rich kornerupine at pressures less than 10 kb (Schreyer and Werding, 1997). However, the prismatine occurs in proximity to low-variance metapelitic assemblages in the surrounding rocks. Specifically, thermobarometry calculations from net transfer and exchange equilibria record temperatures and pressures of 850° ± 20°C and 6.6 ± 0.6 kilobars for orthopyroxene + garnet assemblages and 675° ± 50°C and 5.0 ± 0.6 kilobars for cordierite + garnet + sillimanite + quartz assemblages (Darling et al., 2004). The former assemblage is interpreted to have formed during partial melting whereas the latter assemblage is interpreted to have formed on the early retrograde metamorphic path (Darling et al., 2004). The ∼850°C temperatures derived from the orthopyroxene + garnet assemblage are reasonable for partial melting conditions. Although the cordierite + garnet + sillimanite + quartz assemblage occurs at STOP 6, it and the orthopyroxene + garnet assemblage are better developed further downstream at the second prismatine location (the westernmost open circle in Figure 4). These exposures can be reached by following the footpath on the south bank of the Moose River for a distance of about 400 meters.
Because many of the prismatine-bearing feldspathic lenses are saturated in both quartz and rutile, Storm and Spear (2009) intensely studied the prismatine-bearing lenses as part of a natural test of the titanium-in-quartz geothermometer of Wark and Watson (2006). Storm and Spear (2009) determined a wide range of metamorphic temperatures, specifically from 630 + 63 / -86 to 879 ± 8 °C, but most determinations fell between 700°C and 880°C (see Figure 8a of Storm and Spear, 2009). This is in good agreement with metamorphic temperatures determined by the aforementioned methods (Darling et al., 2004). Storm and Spear (2009) also provide convincing textural evidence that prismatine was locally replaced by leucosomatic quartz, most likely during melting of prismatine. Interestingly, it was the leucosomatic quartz that yielded the highest Ti-in-quartz temperatures (800-880°C; Figure 8a of Storm and Spear, 2009).
The timing of partial melting is unknown but is likely associated with either intrusion of the AMCG suite at ∼ 1160-1145 Ma, or burial associated with the Ottawan phase of the Grenville Orogenic cycle and the associated intrusion of Lyon Mtn. granite at ∼ 1050-1030 Ma (McLelland et al., 2010a).

A5: SEQUENCE STRATIGRAPHY OF PLATFORM CARBONATES: DEVONIAN LIMESTONES OF JOHN BOYD THACHER STATE PARK, SOUTHWEST OF ALBANY, NY
In Honor of Dr. Gerald M. Friedman, a distinguished Geologist, educator, and a mentor. The Text of this trip is adapted and revised from a paper written by Dr. Gerald M. Friedman which was published in the Field trip Guide for the 67th Annual Meeting of New York State Geological Association (October 13-15, 1995) and edited by John I.Garver and Jacqueline A. Smith.
Trip Leader: Mossbah M. Kolkas
Certified Professional Geologist (CPG-10180)
Department of Engineering Science and Physics
The College of Staten Island of the City
University of New York (CUNY)
2800 Victory Boulevard
Staten Island, New York 10314
mkolkas@gmail.com
ABSTRACT
The Lower Devonian strata that crop out on the Helderberg Escarpment illustrate the characteristics of marine platform parasequences in carbonate rocks. In the hierarchy of stratigraphic units, parasequences are a relatively conformable succession of genetically related strata bounded by surfaces of erosion. The parasequences exposed in this escarpment, which include stromatoporoid reefs, stromatolites, and lithified lime mud (micrite) show regressive fades separated by unconformities representing transgressive episodes. The lowermost part of the section exhibits classical karst-generated solution collapse breccia of the kind that hosts oils and gas in the subsurface. The Middle Devonian Onondaga fades at this site are full of coral-reef debris. In the subsurface, Onondaga reefs form gas reservoirs and now serve as reservoirs for gas storage. Sir Charles Lyell visited this classic site, part of the Helderberg Mountains, in 1841 and a monument commemorates his visit and that of Sir William Logan, James Hall, Amos Eaton, and others of the heroic age of Geology.
In the hierarchy of stratigraphic units, parasequences are a relatively conformable succession of genetically related strata bounded by surfaces of erosion. The Lower Devonian parasequences exposed in this escarpment, which include stromatoporoid reefs, stromatolites, and lithified lime mud (micrite) show regressive fades separated by unconformities representing transgressive episodes. The Middle Devonian Onondaga fades Stratigraphically above the rocks at this site is full of coral-reef debris.

A5: SEQUENCE STRATIGRAPHY OF PLATFORM CARBONATES: DEVONIAN LIMESTONES OF JOHN BOYD THACHER STATE PARK, SOUTHWEST OF ALBANY, NY

STOP 1. Location
Figure 2 shows the location of the John Boyd Thacher State Park, where the Indian Ladder Trail reveals the vertical sequence of Lower Devonian limestones that rest unconformably on the Ordovician Indian Ladder beds and Schenectady Formation which can be seen, locally, in gullies below the escarpment (Fig. 3). Entering Thacher State Park from Albany on Route 157 stop at the "Cliff Edge Overlook" for a view of the Taconic and Berkshire Mountains, Adirondacks, Hudson River, and City of Albany; then drive to the next parking lot which has a sign La Grange Bush Picnic Area - Indian Ladder Trail. The trail is open from May 1 to November 1, weather conditions permitting. Descend here for study of the Lower Devonian carbonate fades. Examine also the memorial plaque near the cliff edge at the Mine Lot Creek parking lot which has been attached to a vertical rockwall. It says "in memory of those pioneer geologists whose researches in the Helderbergs from 1819 to 1850 made this region classic ground." The names of these pioneers have been cited under History.

B3: SILURIAN AND DEVONIAN EURYPTERID HORIZONS IN UPSTATE NEW YORK
Samuel J. Ciurca, Jr.
(paleoresearch at yahoo.com)
Rochester, New York
The upper Salina Group consists of a minimum of 70 feet of argillaceous beds (Camillus Formation) that weather rather rapidly. Most beds are mudstones or dolomitic mudstone and shale. The succeeding Bertie Group begins with the deposition of hypersaline „algal‟ mounds and a eurypterid fauna – the Fort Hill Waterlime (see Ciurca, 1973, 1990). Overlying this is the Oatka Shale – dolomitic mudstone with no fossils currently known.
The initiation of Bertie Group sedimentation with a unit of eurypterid-bearing, stromatolitic waterlime set the stage for deposition of overlying units all, in one way or another, deposited during a regime of extensive microbialite sedimentation in the Late Silurian. This, and the numerous eurypterid faunas, typifies the Bertie Group sequence across upstate New York and southwestern Ontario, Canada.
Ciurca (1990 ), in a redefinition of the Bertie Group, added similar lithologic units that occur above the Akron- Cobleskill to the Group (e.g. Moran Corner Waterlime) considering them part of depositional cycles occurring as the result of the shifting of paleoenvironments to and fro during the close of the Late Silurian of the region. We may never know if latest Silurian strata occur in New York as many of the distinguishing zonal fossils may never be found within our sequences. In the meantime, it has been continuously suggested that Eurypterus characterizes the Late Silurian and that Erieopterus characterizes our Early Devonian (at least in the northeast U.S. and Ontario, Canada). The earliest invasion of the Helderbergian transgression may have removed our latest Late Silurian sediments. See Ciurca 1990, Fig. 5, Distribution of Eurypterid-bearing Waterlimes.
Except for the ‘Eurypterus’ pittsfordensis, found at the base of the Salina Group, true Eurypterus are found throughout the Bertie Group and readily distinguish the beds from units such as the Early Devonian Manlius Group or somewhat equivalent beds (Honeoye Falls Dolostone or the Clanbrassil Formation of southwestern Ontario, Canada) – these are replete with the eurypterid, Erieopterus. Figure 1 Algal mounds (microbialites) in the Fort Hill Waterlime at the base of the Oatka Formation downstream from the NY 96 bridge over Flint Creek, Phelps, N.Y. The dam/falls can be seen in the background. The mounds rest on a layer of dolostone bearing abundant evidence of hypersalinity (e.g. salt hoppers).

B3: SILURIAN AND DEVONIAN EURYPTERID HORIZONS IN UPSTATE NEW YORK

STOP 1. Exposures: The Victor and Phelps Members, Fiddlers Green Fm
The type section of the Fiddlers Green Fm. is along Butternut Creek, north of Jamesville, N.Y., where the upper beds form the top of a waterfall. While the rock there is much darker in appearance, the divisions seen here are recognizable there. At the type section there is an upper, very fine-grained dolostone (Phelps Waterlime) with eurypterids and salt hoppers and below, massive beds of the Victor Dolostone
When I first discovered this locality in the 1960s, I called it Con Loc 1 (or Ciurca Locality 56) as we were trying to keep a hoard of collectors from visiting the site in the early years. The site was glacially polished and striated and quite resistant to intrusion, but with weathering and working it slowly over several years, it produced a large number of eurypterid specimens and associated fauna. After a brief interval of several years, when the site was mostly covered with locally-collected drainage ditch material, the site became popular with eurypterid collectors who continued to excavate the rock layers to the state the exposure is today. The research collection I made over the years is available for study at the Peabody Museum of Natural History in New Haven, Connecticut.

Remington Arms Factory on left

Entering Illion Gorge (Steele Creek)
Entering Ordovician Time Zone

Entering Silurian Time Zone

Vernon Red Shale

Syracuse Formation on left (above creek)

McDonald's - rest stop

Erie Canal Museum on right.

STOP 2. Exposures: Late Silurian and Early Devonian Strata (Clockville)
This is an important section, stratigraphically. Rickard (1962) gives a detailed description of the exposed strata. At the base is the uppermost Fiddlers Green Formation (Bertie Group) with eurypterids and salt hoppers. Overlying strata include the Forge Hollow, ‘Cobleskill,’ Chrysler, Thacher and part of the Olney Formations. At least four eurypterid horizons are present in the section. The Silurian/Devonian boundary occurs within the Chrysler Fm. here. At Chittenango Falls, portions of the Chrysler Fm. are rich in horizons of Celestite – a strontium mineral (STOP 3).

STOP 3. Exposures: Late Silurian and Early Devonian Strata (Celestite locality)
For many years, this was a famous mineral collecting locality (mostly Celestite and Calcite). See text for a description of the stratigraphy. Note the massive beds at the base of the cliff – these are the dolomitic facies of the ‘Cobleskill’ Formation. Slightly farther up the road is Chittenango Falls State Park with one of the most beautiful cascading-type waterfalls. Trails take you to the bottom and are well worth seeing. A side canyon just to the north shows what appears to be large ‘algal’ reefs in the Thacher Fm.

STOP 4. Martisco Reef Complex – ‘Cobleskill’ Formation
This is one of the most unusual facies variations of the ‘Cobleskill’ Formation. Sedimentary structures here are interpreted to be part of a highly dolomitized reef complex with silicified fossils, wedging of beds, unusual black chert deposits and succeeding stromatolite beds with breccia and eurypterids. See Ciurca 2005 and
http://eurypterids.net/MartiscoReefComplex.html
for additional comments. Note: Parts of the overlying Chrysler Fm. are well-displayed here.
One other stop is suggested for those interested on this field trip. From this site, take the road back to NY-5 and head west through Auburn and continue to Waterloo, New York. Turn right on NY-96 and head for Phelps where a bridge right in the village goes over Flint Creek (see text). Looking north from the bridge is the Oatka Shale, a rare outcropping. Looking south, below the dam, is lowermost Fiddlers Green Fm. and above the dam is upper Fiddlers Green Fm. including a suggested paleoseismite represented by the Ellicott Creek Breccia. We can collect samples of this for those interested. Many eurypterid specimens have been retrieved from the Phelps Waterlime of this area. Another interesting feature of this locality is the four foot bed of sandstone at the Silurian/Devonian unconformity (just below the Onondaga Limestone).
OHM 2019: Paper company was demolished in 2016.

B4: PALEOECOLOGY OF MIDDLE DEVONIAN BLACK AND GRAY SHALES OF CENTRAL NY
Diana L. Boyer
Department of Earth Sciences
State University of New York at Oswego
Emily Wooton
University of California at Riverside
The dysaerobic zone is a broadly defined biozone that encompasses all reduced oxygen taxonomic occurrences. However, because reduced oxygen conditions include a wide range of bottom water oxygen levels, from the edge of metazoan habitability to near normal marine conditions, a single biofacies is not appropriate to describe all reduced oxygen settings. Further, reduced oxygen conditions in modern oceans are common in a broad range of physical settings and were likely common in an even more diverse range of settings in the geologic past (Tyson and Pearson, 1991; Calvert and Pedersen, 1993; Lyons, 1997; Raiswell and Canfield, 1998; Hurtgen, et al., 1999; Lyons et al, 2003; Levin, et al, 2003). The Finger Lakes region of central New York provides a unique opportunity to examine a range of interpreted relative oxygen levels preserved in black shales. Within these units, taxonomic and paleo-ecologic variations through the dysaerobic zone are recognized. On this trip we will explore localities representing a range of conditions through the dysaerobic zone and highlight the range of organisms adapted to low oxygen conditions and the additive pattern of diversity and life habits through these intervals.

B4: PALEOECOLOGY OF MIDDLE DEVONIAN BLACK AND GRAY SHALES OF CENTRAL NY

STOP 1. Hubbard Quarry
Hubbard Quarry will be on the left side of the road just before the second Lucas Vineyards sign; quarry sits below the road and is obscured by high grass.
This small abandoned quarry is one of the rare exposures of the Geneseo Shale, the lowest unit of the Genesee Formation, in this area. Over 3 meters of black shale are exposed. The Geneseo at this locality is very black with laminated intervals that are clearly anoxic. Silt laminae range from 1 to several mm in thickness and there are some intervals of thick silt ripples preserved at this locality. There are several concretionary layers that are exposed along the floor of the quarry that preserve carbonate-concretions up to 30 cm in diameter. At this locality bedding plane assemblages, most commonly monospecific, reveal dispersed to clumped concentrations of Leiorhynchus quadracostata, Lingula spatulata, Orbiculoidea lodensis, and rare Chonetes sp.. Individuals of L. quadracostata can be preserved inflated and even articulated at this locality and are typically 1.5-3 cm in length. Conversely, individuals of the other brachiopod species are all consistently small (1 cm). The stop illustrates the low end of the dysaerobic zone, although evidence of bioturbation as individual burrows or breaks in lamination are common.

STOP 2: Poormon Road – Fayette Town Quarry will be on the left
This stop exposes the uppermost Skaneateles Formation, the Levanna Shale, and the more resistant, fossiliferous Centerfield Limestone member of the Ludlowville Formation. We will concentrate on the depauperate fossil assemblages of the black shales as an example of intermediate dysaerobic conditions (moderately reduced relative oxygen levels). At this locality, Eumetabolotoechia multicostata, Arcuaminetes scitulus, Devonchonetes coronatus, Orbiculoidea newberryi and Pterachaenia fragilis are commonly found in low diversity and monospecific assemblages on bedding planes. Rare individuals of Allanella tullia, Emanuella subumbona and even Conularia sp. have been identified from this interval. Pelagic “Styliolina fissurella” are abundant on some bedding planes. At some horizons, there are clearly reworked lag deposits comprised mostly of fragmented remains of E. multicostata, but most other individuals are well preserved molds that are likely not transported.
The Levanna Shale at this locality preserves intervals of anoxia as barren laminated shales, as well as intervals of significantly higher relative oxygen levels as indicated by horizons with moderate diversity and abundance of benthic macrofauna. Detailed trace fossil analysis supports these interpretations.

STOP 3: Paines Creek will be down the hill
Paines Creek is the type section for the Ledyard Member of the Ludlowville Formation and can be accessed below the closed bridge. This black shale overlies the Centerfield Limestone Member that is exposed downstream as the cap of Moonshine Falls. At this locality, approximately 4 meters of black shales of the Ledyard Member are exposed in the creek bed. Fossils are dispersed and include Eumetabolotoechia multicostata, Arcuaminetes scitulus, Devonchonetes coronatus, Orbiculoidea newberryi, Lingula spatulata, Pterachaenia fragilis, Nuculites oblongatus, Nuculoidea sp. and Hollandclarkeia jennyae. Benthic macrofauna at this locality are found dispersed within sediments that range from laminated through almost completely bioturbated. Monospecific occurrences are present at this locality, but there are only rare densely packed associations.
This locality again records a range of bottom water oxygen conditions from anoxic through moderately oxygenated based on the variable diversity of benthic macrofauna, which also corresponds with ichnological data. This locality was selected to reflect intermediate conditions of oxygen stress.

STOP 4: Long Hill Road Cut
Parking will be on the right at a gravel turnoff. Locality is on the south side of the road.
This section exposes uppermost portion of the Moscow Formation, including a near complete succession of the Windom Shale and Tully Limestone, and the overlying Geneseo Shale on the south side of Long Hill Road. The black shales of the Geneseo are barren at this locality. The Windom Shale preserves several coarsening upward shale-siltstone cycles through an overall shallowing succession that is overlain by the thick Tully Limestone. Within the grey shales of the Windom are moderately diverse fossil assemblages, with some dense concentrations that are interpreted to be storm events. Intervals within this succession are interpreted to represent deposition under reduced oxygen conditions at the upper end (more oxygenated) of the dysaerobic zone based on body fossil diversity and trace fossil composition.
Common benthic macrofauna within these intervals include, the Rhynchonelliform brachiopods Eumetabolotoechia multicostata, Arcuaminetes scitulus, Devonchonetes coronatus, Allanella tullia, Ambocoelia umbonata the “inarticulate” brachiopods Orbiculoidea newberryi, Lingula punctata, bivalves Pterachaenia fragilis, Nuculites oblongatus, and Nuculoidea sp. and the trilobites Eldregeops rana and Hollandclarkeia jennyae.
This locality represents the upper end of the dysaerobic zone in which oxygen conditions are not at levels interpreted to be normal marine levels due to reduced diversity and ichnological features, but are higher when compared with other black shale intervals seen on this trip.