SLUICE POND GEOPHYSICAL SUB-BOTTOM SURVEY, LYNN, MASSACHUSETTS

Holocene climate changes are preserved in lakes all across the world, and geophysical surveys can provide groundwork information about these sediments to assist in coring work. In this study, a sub-bottom survey was conducted in Sluice Pond, a publicly accessed pond located about two miles south of Lynn Center, Lynn, Massachusetts. This work was assembled in order to improve our understanding of the pond's preserved sediment characteristics. The survey was conducted using the Edge Tech 3100-P portable sub-bottom profiling system and SB-424 tow-fish. We totaled ten surveyed lines at CHIRP frequencies in the range of 4 to 24 kHz. The pond's sediment thickness, depth to Pleistocene acoustic basement, and unusual acoustic features were analyzed. An isopach map and depth to acoustic basement map were produced to exhibit the data. Data reveal a maximum thickness of Holocene sediment of about 5 meters. This unit pinches out in shallow water, and is underlain by an impenetrable unit, most likely Pleistocene in age (Ritch and Hubeny, 2008). A second acoustically impenetrable area on the southwest side of the main basin was observed in the Holocene unit. The characteristics of this area, we believe, are a result of ground water flowing into the pond along local bedrock fractures. These results will assist in future coring studies of Sluice Pond, Lynn, Massachusetts, and may help our understanding of local groundwater flow into the pond.