HIGH-LEVEL PROGLACIAL LAKES, SOUTHERN CAYUGA VALLEY, NEW YORK

Ice retreat from the Valley-Heads moraines (VHM) positions in the Finger Lakes of New York resulted in impoundment of pro-glacial lakes within the troughs. Previous workers have correlated hanging deltas to define a number of proglacial lakes in the Cayuga trough. While re-investigating these major lakes, we have identified a series of local high-level lakes that were impounded in tributary valleys as ice retreated from the uplands but persisted in the main north-south trough. Retreat of the ice lobe in Cayuga Valley blocked the outlets of both Enfield Glen and West Branch Cayuga Inlet during initial retreat from the VHM north of Spencer. This blockage of Cayuga Trough by the valley glacier and an outlet through the VHM at Pony Hollow formed an initial high-level Lake Enfield, which existed at about 1250 feet (380 m). The Pony Hollow outlet was abandoned as the Cayuga trough glacier retreated far enough north to allow water to escape between the glacier and the north side of Benjamin Hill south of Newfield. As the elevation of Lake Enfield lowered, a drainage divide developed just south of the headwaters of Fish Kill near Newfield at a modern elevation of 1175 feet (358 m), separating Lake Enfield into two bodies (including a short-lived southern lake we name Lake Newfield). Meltwater escaping via this outlet carved a bench at an elevation of 1090-1140 feet (332-348 m) into the west side of the main Cayuga Valley wall south of Newfield. The bench is marked by kettle topography, likely from ice that calved from an ice margin at Lake Enfield. Lake Newfield gradually dropped to the 1130-foot (345-m) level through outlet drainage and quickly disappeared. Subsequently, water from Lake Enfield continued to use the Fish Kill outlet, carving a spillway which is preserved today. Thus the small high-level lakes had complicated histories, strongly affected by both ice dynamics and local outlets and overflows.