VARVE CHRONOLOGY FROM GLACIAL LAKE WARRENSBURG: A PRELIMINARY STUDY OF A FORGOTTEN GLACIAL LAKE NEAR WARRENSBURG, NY

As the Laurentide Ice Sheet retreated from the Adirondack region of upstate New York ~14 cal. kya, a succession of glacial lakes formed, including Lake Warrensburg. Although there are several estimates of its timing and extent, there is very little known about glacial Lake Warrensburg. The purpose of this study is to collect and analyze varves from Glacial Lake Warrensburg, to contribute to the existing chronology regarding the formation and drainage of the lake, and contextualize the retreat of the Laurentide Ice Sheet from the Hudson/Champlain Valleys. We collected two overlapping cores containing 0.9 m of glacial varve sediments from a site ~10 km north of Lake Luzerne, NY, within the estimated area of glacial Lake Warrensburg. At least 15 m of varve deposits exist at this site, and may also be found further north in the Lake Warrensburg Basin as far as the Schroon Lake Valley. The cores were split and partially dried before annual couplets were defined and measured. Sediment analysis was conducted using a petrographic microscope. One conifer macrofossil was collected in the field for radiocarbon dating. We currently hypothesize that the varves were indeed deposited by glacial Lake Warrensburg between ~15.3-13.9 cal. kya. The 0.9 m section contains 8 full years of thick and irregular ice-proximal sediments containing predominantly fine quartz grains. It is possible that Adirondack alpine glaciers are the sediment source for these lacustrine deposits.