Using shallow seismic reflection to resolve the glacial history along the southern coast of Cape Cod, MA

Debate surrounds the glacial history of southern Cape Cod as current data and analyses are insufficient to clearly discern the details of the area's glacial events. A shallow seismic reflection survey at Mashpee, MA imaged three reflection surfaces that correlate well to the area's stratigraphy. The data suggest pre-Laurentide deposits rest on the deepest reflection, bedrock. The reflection surface above the pre-Laurentian deposits has a concave downward section interpreted as a 325 m wide and 35m deep channel, which is filled with glaciolacustrine sediment. The top of the glaciolacustrine layer is imaged by a reflection that suggests the glaciolacustrine layer was eroded due to the drainage of a proglacial lake. The thick sequence above the shallowest reflector is an interval of outwash sediment, deposited during the ice sheet's final retreat.