STRANDLINE FEATURES IN THE HUDSON-CHAMPLAIN REGION REVEAL WATER PLANES WHICH TILT AT 4.0FT/MI

Surficial geologic mapping of Brandon, VT, revealed several different strandline features from those recognized by Connally (1970). These data were integrated with new and existing data through the Troy South, NY, quadrangle. This work in progress identifies 41 strandline features consisting of deltas, beaches and sand spits. The elevation of each feature was determined on a topographic map with a range of error assigned to be +/- 10 feet or +/-3 meters. Isobases in the H-C divide region bend to follow the curved axis of the divide region. The trend line used to plot the features approximately parallels the H-C barge canal and Wood Creek, and then parallels the Hudson River south of Fort Edward. Strandline features fall on 5 water planes which tilt at 4.0ft/mi +/-0.2ft/mi or 0.75m/km +/-0.03m/km and represent these glacial lakes: *ABI Albany I, *ABII Albany II, *QS Quaker Springs, *CV Coveville, *FAI Fort Ann I. I propose that EACH transition was induced by a catastrophic flood from outside the H-C basin. ABI-ABII dropped levels 80ft accomplished by a flood pulse from the Ontario Lowland down the Iromohawk with discharges as calculated by Wall(1995) and was likely from an Early Iroquois or Hyper-Iroquois lake. ABII-QS dropped levels by 40-50ft as the result of a second flood pulse down the Iromohawk, perhaps due to the Watertown phase transition. QS-CV dropped water level 60-80ft and this flood and subsequent nominal Iromohawk discharge utilized the Mohawk channels. CV-FAI was the result of the first flood pulse of waters escaping around Covey Hill as most recently discussed by Rayburn (2004) and Rayburn et al (2005a, 2005b). The Main Iroquois to Frontenac transition may have triggered the contemporaneous CV-FAI transition followed quickly by the confluence of Frontenac with FAI (Rayburn et al, 2005b). Donnelly et al (2005) and Rayburn et al (2005b) discuss the possible impact of flood pulses on thermohaline circulation in the North Atlantic Ocean. The former proposed one flood may have been responsible for the Intra-Allerod cold period. Which flood was responsible for this cold period remains unknown as the timing of Lakes ABI, ABII and QS remain poorly constrained. Most interesting is the prospect that EACH of the flood pulses may have had a climatic impact and this should be discernible in the marine and/or ice core data.