GRAVIMETRIC STUDIES OF IN-FILLED KARST STRUCTURES IN THE COBLESKILL PLATEAU, CENTRAL NEW YORK

The Cobleskill Plateau of central New York is part of the larger Helderberg Plateau, comprised of Silurian and Devonian limestones which display excellent caves and karst landforms, subsequently altered by glaciation. The glacially mantled and in-filled pre-existing karst topography of the area caused hydrologic changes that affect current karst flow paths. Determining the nature of the antecedent topography, and the location of cave passages, is critical to a full hydrologic analysis of the Cobleskill Plateau. A series of gravity traverses were conducted using a Worden Gravity Meter to acquire readings along transects with the intent to validate the subsurface location of an occluded abandon trunk passage connecting Howe Caverns and McFail’s Cave near Cobleskill, New York. The importance of finding or not finding the abandon trunk passage is to increase the understanding of subsurface geology, potential hazards and controls on pre-glacial groundwater flow in the region. Gravimetric analysis has been used successfully to locate a glacially in-filled valley, and how that valley relates to known cave passages in the area, but this investigation is the first to attempt to locate the link between the two cave system segments. The findings of this study conclude that subsurface anomalies do exist at the expected locations and can be identified through the use of gravity surveys. The exact shape, size, or type of anomaly cannot be definitively determined by this study but can be fit to various models which support the existence a void. The exact nature of the anomalies may be determined by further exploration of the subsurface in the region and from within the cavern, if access becomes possible.