MAPPING HETEROGENEOUS GLACIAL SEDIMENTS IN THE FINGER LAKES REGION OF NEW YORK

摘要

The Finger Lakes of Central NY are among the most interesting geologic locations on the planet. What was once a glacial sculpting of sedimentary rocks of the Allegheny Plateau resulted in deep glacial troughs forming the Finger Lakes. These glacial carvings started around two million years ago. Today the geologic understanding and history of the Finger Lakes continue to be a source of new investigations and discoveries. In the summer of 2016, resistivity surveys were performed in several locations on the northeastern side of the Cayuga Lake to aid in the glacial interpretations made of this region. An MPT DAS-1 Electrical Impedance Tomography System was used with electrode spacing ranging from 2m to 5m in dipole-dipole array pattern. The primary survey location is in farm fields adjacent to a ravine exhibiting several unique stratigraphic markers for the area. Bedrock outcrops, boreholes, and preliminary seismic surveys indicated the presence of a bedrock valley filled with glacial sediments. The geophysical investigations were designed to map the heterogeneous glacial stratigraphy of the filled valley. The secondary site is near a ravine adjacent to a hops farm. Wells drilled in this area had been unproductive, causing a shortage of water for irrigation. However, signs of water leaking from the ravine walls and forming streams at the base of the ravine indicated a potential spring source. Resistivity surveys were used to locate those potential spring sources of water. The results of the geophysical investigations describe the heterogeneity of the glacial landscape in the bedrock valley and provide a spring source for irrigation at the hops farm.