Neotectonic investigations in Southern Ontario. Prince Edward County - Phase 2

This report summarizes the preliminary results of geological and geophysical investigations and offshore side scan sonar surveys of the bedrock and unconsolidated sediments in Prince Edward County, Southern Ontario, by the Ontario Geological Survey in 1989. Investigations were focused on deformations in the bedrock and the surficial deposits. Some of these deformations may be neotectonic in origin. Low magnitude seismicity in the Prince Edward County region appears to be spatially related to a major regional fault system that crosses Lake Ontario and consists of the seismically active Clarendon-Linden Fault System in New York State, the Picton-Napanee and Rideau Faults, the Frontenac-Sharbot Lake Terrane Boundary and the assumed Salmon River Fault in Ontario. Detailed observations were made in the Long Point study area and the Mountain View and Picton Quarries. Bedrock structural features were documented, including: joints; normal, reverse and strike strip faults; brittle folds; and Jurassic age ultramafic dyke. Detailed refraction seismic surveys were conducted across a local fault and possible fold structures. Magnetic surveys, conducted in conjunction with the offshore side scan sonar surveys, documented large magnetic anomalies southeast of Point Petre and at the northeast end of Long Reach. Side scan sonar surveys of the lake bottom to the east of Point Petre confirm the presence of pop-ups in that area of the lake bottom which is immediately adjacent to where pop-ups are observed on land. The pop-ups present in the lake bottom have similar orientations to those mapped in the study area