DEPOSITIONAL CHARACTERISTICS OF PRO-GLACIAL LAKE WARRENSBURG: EVIDENCE OF VARVE SEDIMENT DEFORMATION

Glacial Lake Warrensburg occupied the upper Hudson River Valley during the Laurentide deglaciation, but its' age has not yet been definitively matched to the North American Varve Chronology. As part of a paleoclimatology class, we continued to study the glacial lake sediments and varves found along the Buttermilk Brook Recreation Area. Using a Ridge-style percussion varve coring device and sharpened lengths of 4" schedule 40 PVC pipe, we recovered three cores from immediately below the overlying fluvial sand terrace. Filled core tubes were dug from a sloping outcrop.

Cores were returned to the lab, where they were sectioned and split. Core faces were cleaned to show the stratigraphic features. We measured about 50 fining upwards packets, interpreted as seasonal proglacial lake varve deposits. Varve thickness varied considerably from 5mm to over 65mm. We observed grain size variations, and soft sediment deformation features. One core contains a set of tilted layers between horizontal strata. Microfossils were not yet found.

Future work may include more detailed stratigraphic description, XRF analysis, sieving for microfossils, and additional fieldwork.