Abstract

Upper Pleistocene deposits with organic materials at Nichols Brook and Winter Gulf sites about 50 km south of Buffalo, New York, provide information on the glacial sedimentation, date of ice retreat, and paleoenvironment in western New York State. Four 14C dates from successive levels of woody peat above outwash at Nichols Brook indicate that glacial retreat from the Lake Escarpment–Valley Heads moraine just to the north had probably occurred by 15,000 B.P. (during the Port Bruce Stadial or following Mackinaw Interstadial). At Winter Gulf, dates of 12,730 ± 220 and 12,610 ± 200 B.P. on wood from peat are palynologically correlated with a similarly dated horizon at Nichols Brook and provide minimum ages for lowering of glacial Lake Whittlesey and ice retreat from the correlative Hamburg moraine.

Pollen assemblages associated with the interval between 14,900 and 10,000 B.P. are at both sites dominated by spruce; cones and needles of white spruce and tamarack are also present. This and the lack of abundant birch or balsam fir suggest an open boreal woodland vegetation similar to that of subarctic Ontario between lat 50° and 52°N. Floral evidence is lacking for tundra vegetation or for more than a slight warming trend during the 14C-dated interval. In contrast, analysis of insect fauna from the Winter Gulf spruce horizon that accumulated within 21 to 80 km of the ice margin suggests a shift to markedly temperate conditions.

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