A2:PLEISTOCENE GLACIATION OF THE TIOUGHNIOGA RIVER AND FALL CREEK VALLEYS
Amanda L. Buboltz and Peter L.K. Knuepfer
Department of Geological Sciences
Binghamton University
Binghamton, NY 13902-6000
INTRODUCTION
The Pleistocene Epoch in eastern North America was characterized by a series of glaciations, the most recent of which was the Wisconsinan (from about 11.7 to 11.9 ka B.P.). Advance and retreat of glacial ice resulted in erosion of the landscape and the formation of landforms and deposition of glacial and related deposits. At the peak of the Wisconsinan glacial period, the Laurentide Ice Sheet extended from Canada and covered most of eastern North America, with its margin located in Ohio, northern Pennsylvania, northern New Jersey, and extending through Long Island into the Atlantic off the southern coasts of Connecticut, Rhode Island, and Massachusetts. Deposits of the previous Illinoian glaciation can be found to the south of the Laurentide margin, but are mostly lacking to the north of the margin as a result of erosion and reworking of sediments and deposition during the Wisconsinan glaciation (Randall 2001).
In New York State, glacial ice flowed south/southeast from Canada, as indicated by glacial striations deposits/landforms. Valleys parallel to ice flow were typically eroded into U-shaped glacial valleys, whereas valleys perpendicular to flow were infilled with glacial deposits and, upon ice retreat, eroded by meltwater and rivers. Over successive glaciations, through valleys such as the valleys of the Finger Lakes were carved out, and glacial landforms and deposits, including the drumlin fields of the Ontario Lowlands in western New York and several moraine systems were deposited/formed.
In the Late Wisconsinan Last Glacial Maximum (LGM), following ice advance to the position of the terminal moraine around 20,000 (radiocarbon) years ago, ice began to retreat back to the north. The retreat phase in the Appalachian Plateau of New York State was characterized by a relatively rapid retreat of ice in the uplands, while ice tongues remained longer in glacially eroded U-shaped valleys. Valley ice tongues retreated through the processes of back- and down-wasting (Fleisher 1993). Back-wasting involved active ice retreat and typically occurred in through valleys. Down-wasting was characterized by stagnant ice retreat and took place in smaller valleys (Fleisher 1991).
Ice retreat from the LGM was accompanied by formation of lakes in front of the retreating ice margin, especially where previously deposited glacially derived sediment blocked southward drainage. At least one period of stagnation and readvance of ice resulted in the deposition of the Valley Heads Moraine (Stops 1, 3, and 4) within several valleys of Central and Western New York (Fig. 1) (Miller et al. 1998). The Valley Heads Moraine is a characteristic ablation or dead ice moraine that formed as a result of ice stagnation, as shown by the large kettle ponds and lakes in the Tully region (Stop 1) confined between the moraine to the north and the valley train to the south (Fleisher 1991). Deposition of the Valley Heads moraine resulted in the formation of large proglacial valley train sequences confined to valleys south and east of the moraine (such as the Otisco, Factory Brook, West and East Branch Tioughnioga, Otter/Dry Creek, Trout Brook, and Main Stem Tioughnioga valleys, which are the subject of this field trip). Retreat of ice north from the Valley Heads position also led to development of large proglacial lakes.
Ice re-advance and the resulting deposition of the Valley Heads Moraine reorganized pre-LGM drainage divides in several of the through valleys in central New York. Two segments of the Valley Heads Moraine provide drainage divides and boundaries for the Tioughnioga and its associated drainage. The Tully Moraine (Stop 1) forms the drainage divide at the northern end of the West Branch Tioughnioga Valley. Drainage to the north of the moraine, in the Onondaga Trough, flows north towards the Seneca River and Lake Ontario, while drainage to the south of the moraine flows south through the West Branch and Main Stem Tioughnioga River to the Chenango River and eventually the Susquehanna. To the southeast of Cortland, the South Cortland Moraine (Stops 3 and 4) forms another drainage divide. Flow to the west of the moraine is west-southwest through the Fall Creek Valley to Cayuga Lake. To the east of this moraine, Dry Creek and Otter Creek flow east-northeast into the West Branch Tioughnioga River, which then turns southwest down the Main Stem Tioughnioga.
This trip focuses principally on the deglaciation of the Tioughnioga Valley between Tully and Whitney Point, NY, with additional examination of the Fall Creek Valley between Cortland and Ithaca, NY. The goal is to illustrate most of the key morphologic and sedimentologic features that characterize active and dead-ice retreat of the LGM ice through this area of central New York. In addition, exposures in Fall Creek Valley allow us to examine some pre-LGM deposits.

A2:PLEISTOCENE GLACIATION OF THE TIOUGHNIOGA RIVER AND FALL CREEK VALLEYS

Note the gravel pits in outwash deposits along route 11 in Homer.

Preble Swamp area
Note the gravel exposure in the kame terrace to the east. The Preble swamp is a kettle, possibly a dead ice sink, formed as an ice block broke off from the actively retreating ice margin and was buried beneath glacial outwash. As the ice melted, outwash deposits collapsed downward, forming a kettle at the surface. To the east of the kettle, a kame terrace formed as glacial meltwater deposited sediment between the ice block and the valley wall. As the ice melted, the sediments collapsed and a kame terrace resulted. An exposure in this terrace is located just north of the swamp.

STOP 1. Tully Lakes Kettles and Kames
Green Lakes and the rest of the Tully Lakes, ponds, and depressions, are kettles. These lakes formed as ice stagnated and blocks of ice were buried beneath outwash deposits. As ice melted, outwash deposits collapsed downward, forming depressions and kettles. Some of these depressions were below the water table and thus filled with water, forming kettle ponds and lakes. In areas where depressions were found on the ice surface, sand and gravel was deposited by glacial meltwater flowing over the ice surface. As the ice melted, these deposits were lowered to the valley floor, forming mounds known as kames. The gravel pit to the south of Green Lakes is excavated into such a kame deposit. Overall, the deposit is poorly sorted, with larger clasts of gravel in a sand matrix. Clasts are mostly of local origin, with some exotics, including granites, metamorphics, red sandstones, and limestones transported to the region from areas to the north. Gravels commonly contain calcium carbonate rims, and large post-Pleistocene conglomerates composed of sands, gravels, and cobbles, cemented with calcium carbonate, are found at the site. This Tully Lakes moraine complex commonly is considered part of the Valley Heads Moraines, although the cross-section of Kappel and Miller (2003) implies that this Valley Heads morphology may be developed on a relatively shallow till deposit that in turn overlies laminated silt and clay over a buried till deposit. Thus, whether this area represents the “true” Valley Heads Moraine — or a slightly younger recessional moraine formed during retreat from the Valley Heads position — is unclear.

Note Song Lake, another kettle lake, to the left.

The Otisco-West Branch Tioughnioga Valley confluence.
Glacial and alluvial fan deposits from the Otisco Valley control the location of the West Branch Tioughnioga River at this junction, with the river confined along the eastern valley wall. Valley Heads Moraine deposits and Otisco Lake (one of the Finger Lakes) are found up the Otisco Valley to the northwest.

STOP 2. Preble Lakes
These lakes are large kettles that occupy most of the valley width, and are possible dead-ice sink deposits. They were formed in association with the Preble Swamp to the north, as ice blocks detached from the retreating ice margin and were buried beneath glacial outwash deposits. As ice melted, outwash at the surface collapsed, forming depressions that intersect the water table. Kettle lakes and ponds of the Preble area resulted.

Note large active EZ Acres gravel pit to the left.
This pit is in a kame terrace, deposited as glacial meltwater flowed between the ice surface and the valley wall. Although this is an excellent exposure through the entire kame terrace deposit, the height of the quarry wall at the time of this writing presupposes a safe visit.

Note exposure of bedrock as you enter Homer Gulf
Note exposure of bedrock as you enter Homer Gulf; this would be the equivalent of the valley-wall side of the kame terrace.

STOP 3. Lime Hollow Nature Center Trails
This area contains a pitted, hummocky kame and kettle landscape, with wetlands located in low lying depressions and kettles. Walk along the trail, heading southeast. Pass the trail sign, continuing straight. Cross the field, heading towards a mostly reclaimed gravel exposure. This is an exposure in a kame deposit. The unit overall is poorly sorted and matrix dominated, with grain sizes ranging from sand and silt to cobbles. Clasts include local sandstones and shales, as well as limestones, granites, red sandstones, and other exotics transported to the region from the north.

Lime Hollow Visitor Center for LUNCH STOP

STOP 4. O.D.von Engeln Preserve at Malloryville
This preserve is named for Otto D. von Engeln, late Professor of Geology at Cornell, who bequeathed much of the site in order to preserve the glacial geology and wetlands ecosystem; von Engeln was keenly interested in the glacial history of New York. The preserve is located within glacial deposits associated with deposition of the South Cortland (Valley Heads) Moraine. The area contained stagnant ice that resulted in the production of kame and kettle topography, as well as an esker. The site also contains abundant wetland types, including marshes, bogs, fens, and swamps, within depressions and low, poorly drained areas. Wetlands are in low-lying areas and depressions that formed as kettles as buried ice blocks melted and overlying deposits collapsed downward. The esker was deposited as a subglacial meltwater channel beneath stagnant ice.

STOP 5. Varna High Banks.
In this section of Fall Creek Valley, a large meander loop of Fall Creek cuts into blue-gray till and associated deposits. Basal deposits, exposed occasionally along the base of the exposures on either side of the creek, consist of laminated glacio-lacustrine silts and clays. Elsewhere in the valley these varved sediments, which overlie strongly weathered till (Bloom 1986), have yielded radiocarbon ages in excess of 35,000 14C yr B.P. (Muller and Cadwell 1986). Lodgement till is typically exposed at the base of the southeastern bank of Fall Creek. This unit is highly compact, poorly sorted and matrix dominated, with clasts ranging from angular to rounded in shape. Some clasts contain glacial striations. Grain size ranges from clay to cobble, with an assortment of clast lithologies, including sandstone, granite, limestone, quartzite, and others. The lower layer of this till are contains a higher percentage of gravel and is better sorted, with some stratification. Till in this bank has been eroded by Fall Creek and is overlain by alluvial deposits.
Along the northwestern side of Fall Creek, the Varna High Banks are exposed. The lower section of this deposit is poorly sorted and matrix dominated, with grain size ranging from clay to cobbles. Clasts are predominantly of local origin, with some exotics. Precipitation of calcium carbonate has led to the cementation of the lower unit. Some layering and stratification is present in the unit, with interbeds of unsorted material and sorted, layered sands and gravels. The lower unit of the Varna High Banks is overlain by a blue-gray glacial lodgement till. This is the same till as that exposed in the eastern bank. The uppermost section of the till shows evidence of being reworked by flowing water. Glacio-lacustrine deposits from Freeville-Dryden Lake overlie the till. This unit has been eroded from the eastern bank. Grains consist primarily of silt and fine sand.

Caroline area.
Note truncated spur ridges ahead that dominate the narrowing valley through which route 79 passes. The morphology of the valley-facing slopes is typical of east-west valleys in this part of New York: a steep north-facing slope on the south side of the valley, a gentler south-facing slope on the north side. Coates (1966) attributed this morphology to till shadows, formed because south-flowing ice dropped its basal load at the stress reduction caused by the north valley wall and had increased erosional capacity with increased basal stress at the south valley wall.

Richford.
This is the through valley that connects Owego Creek with Dryden and, ultimately, the Fall Creek Valley.

Michigan Hill Road.
This is the approximate location of the west end of the Lisle/Dudley Creek esker, which continues east for approximately 5 miles (8 km). The esker is intermittent at this west end, but becomes more continuous to the east (except where it has been quarried away).

STOP 6. Lisle Esker.
Most of the deposit has been removed at this location during construction of the speedway parking area, but part of the esker is exposed to the west of the parking area. This esker was deposited within a fluvial channel beneath (likely) stagnant ice. Clasts range from sand to cobble in size, and are rounded. The unit is stratified and contains well-sorted lenses of sand and gravel. Clast lithologies are predominantly of local origin, with a small percentage of exotics.

Center Lisle; east end of Lisle Esker.
Continuing to the east, the valley margins are marked by a series of kame terrace deposits.

STOP 7. Kame Terrace Within Northern Cutbank of Dudley Creek.
Dudley Creek has been undercutting its north bank at a number of locations through this narrow valley. This has produced a number of large slumps, the best exposed of which is here. Most of the slumps expose stratified sands and gravels. The deposits at this location also are stratified, with a massive, well-sorted sand unit in the lower section overlain by a unit of interbedded sand and gravel. The lower sand unit contains cross beds and collapse structures. Layers within the interbedded unit dip upstream and contain large scale cross beds.

Owen Hill Road climbs onto broad kame terrace surface.
This is the same kame that is exposed in the bank of Dudley Creek (Stop 7).

Crest of Owen Hill Road onto kame terrace surface.

Descend onto lower kame terrace surface.

Begin descent from lower kame surface.

STOP 8. Kame Terrace
This terrace is a continuation of the deposit along the northern wall of the Dudley Creek Valley. Clasts within this deposit are rounded and range from fine sand to boulders. The lithologies are mostly of local origin, but exotics, including red sandstone and metamorphics are also found. Clasts are oriented into the deposit, indicating meltwater flowing south toward Owen Hill Road and parallel to the Tioughnioga Valley. The sand and gravel near the top of this deposit is cemented by calcium carbonate.

STOP 9. Kame Delta
This deposit is above the Tioughnioga Valley on the eastern valley wall. A large kame terrace with a working sand and gravel operation is found below this deposit. Here, the kame deposits are deltaic. The delta deposit is stratified, with topsets and foresets exposed. A channel deposit is present in the upper left section of the deposit, with a channel bar to the right. A fault offsets channel sand beds, and gravels along the fault have slumped and rotated. Overall, the deposit is poorly sorted, but individual well-sorted layers with imbricated pebbles are present.

Note the working gravel pit and kame terrace exposure to the right
Note the working gravel pit and kame terrace exposure to the right, along the east valley wall. This is the gravel pit and kame surface west of and below Stop 9.

STOP 9B. Optional Stop. Marathon Glacial Landscape Overview
The valley walls at Marathon contain large kame terrace deposits, including a deposit at the location of the graveyard just north of the Interstate 81 on-ramp. A terrace is present to the southwest, across the valley from the high school. Note the relatively flat topography of the terrace surface. Kame terraces are also found to the south of Marathon, just north of the Cortland – Broome County boundary.

Head north along the east valley wall.
Note the narrowing of the Tioughnioga Valley and the bedrock outcrops along the east valley wall.

Likely Location of a pre-glacial drainage divide.
Just north of Messengerville is the likely location of a pre-glacial upland and valley drainage divide. Drainage north was toward Cortland and drainage south was toward Marathon. As a result of glaciation, this drainage divide was eroded and the Tioughnioga River now flows south from Cortland toward Marathon and Whitney Point.

Abandoned gravel pit just east of road.
Pit exposes more than 30 m of stratified sand and gravel; most is cemented by calcium carbonate. This deposit may be part of a recessional moraine that was a valley plug deposit, impounding a lake that deposited thick glacio-lacustrine sediments now buried beneath the Tioughnioga Valley to the north.

Hoxie Gorge Road.
Spectacular bridges take I-81 across this deep gorge, which is incised into glacial deposits and (mostly) bedrock.

Polkville.
This area is within the valley of the Main Stem Tioughnioga. The Trout Brook Valley merges with the Main Stem Valley from the east in this area. Pre-glacial drainage in this area was to the northwest, as shown by the orientation of the Trout Brook and Tioughnioga valleys, the change in valley width from northwest (wide valley) to southeast (narrow), and the northwestward sloping longitudinal bedrock profile within the Tioughnioga Valley. A sand and gravel mining operation in glacial outwash deposits is located within the valley, just southwest of the highway. Beneath the outwash deposits, a thick layer of glacio-lacustrine silt and clay is present. This silt and clay was deposited in a large glacial lake that extended to the Valley Heads Moraine deposits. The lake outlet was located south of Blodgett Mills, quite possibly impounded by the valley plug deposit described above at mile 111.3.

Pendleton Street.
A kame surface is located to the left (south) along the southern valley wall here at Cortland. The terrace deposits, as shown by soil parent materials, extend southwest along the Otter Creek Valley. Additional kame terraces are found along the northern valley wall of Otter Creek. These kame terraces may be part of a moraine that was deposited as ice retreated northward from the region, possibly pinned against the high topography south of Cortland. Within the valley itself, outwash deposits overlie glacio-lacustrine deposits, buried outwash, and till.