Strike-Slip Displacement on Faults in Triassic Rocks in New Jersey

Abstract

The Hopewell and Flemington faults in New Jersey are inferred to extend 10 to 15 miles or more farther north than their previously mapped northward limits. The Hopewell fault, previously known to show dip-slip displacement of 10,000 feet or more, is inferred to include as well a right-lateral strike-slip component of 12 miles on the basis of apparent displacement along its northern extension of the crestal traces of two partial anticlines which are held to be displaced segments of the same transverse structure, here called the Somerville anticline. An unknown amount of strike-slip displacement may have occurred also on the Flemington fault, if the apparent offset of the Ramapo fault at the northwestern border of the Triassic outcrop belt is explained as the result of displacement of a formerly continuous northeast-trending, southeast-dipping fault by a north-trending vertical extension of the Flemington fault.