STRATIGRAPHIC AND CHRONOLOGIC CONSTRAINTS FOR THE MAXIMUM AGE OF MIS 2 GLACIAL ONSET IN UPSTATE NEW YORK STATE, USA

In this study, we examined the previously reported chronological data to evaluate the maximum age of glacial onset during the MIS 2 Nissouri Phase ice advance in upstate New York. Prior to this study, data was available from the Lord Hill site and Genesee Valley region (Muller et al., 1988; Miller and Calkin, 1992; Young and Burr, 2006) in western New York, and Port Washington, Long Island in extreme southeastern New York (Sirkin and Stuckenrath, 1980; Stanford, 2010; Stanford et al., 2020). Newly collected stratigraphic, structural, paleoecologic and multi-method chronological data in the eastern Finger Lakes indicate that the MIS 2 ice advance of the Ontario Lobe in central New York was entering the north end of the eastern Finger Lakes, 170 km north of the LGM at between 26,000-27,000 cal yr BP. Our data indicates the Ontario Lobe response lagged the ice advance in New England and Hudson Lobe in southeastern New York which was at or approaching their respective glacial maximums at this time. The maximum age of the Ontario Lobe ice advance determined from this study correlates strongly with chronological data from southern Ontario and Ohio. In Ohio the Huron-Erie Lobe was expanding into western Ohio but did not reach its glacial maximum until ~21,000 cal yr BP.

Deposits in excess of 300 m thick at the southern end of the Finger Lakes indicate either substantial sedimentation rates and\or a complex glacial history, probably both. In order to fully evaluate the dynamics and chronology of the Ontario Lobe in south central New York, deep continuous core drilling is needed similar to that undertaken in southern Ontario (Burt et al. 2015; Mulligan and Bajc, 2018). The plant macrofossils from the LT-Gorge site indicates that cool tundra conditions persisted in the late stages of the Farmdale Phase prior to the MIS 2 onset. This paleoecological data concurs with similar interpretations at Lord Hill in Western New York (Miller and Calkin, 1992) and southern Ontario (Berti, 1975). Further study of the landforms and deposits of the Ontario Lobe in the southern tier in central New York may provide additional information to compare and contrast temporal variation in ice sheet maximum positions between New England and the Midwest.