Inferred Mesozoic faulting in Finnmark: current status and offshore links

Abstract

An earlier compilation of the post-Caledonian fault system in the Caledonian domain of Finnmark is reassessed in thelight of more recent diverse data acquired from a combination of general geology onshore, well data and seismic reflection profiling in the offshore areas of the Finnmark Platform, and evidence of multiphase faulting farhter south in Troms and Nordland. While age determinations on fault rocks are still lacking in Finnmark, th character and trends for faults on-land, to the south, and offshore in the Barents Sea domain, allow deductions to be made regarding the likely ages and reactivation histories of some of the major faults. Taking the spesific example of the NE-SW-trending Vargsund-Langfjorden fault, a component of Mesozoic reactivation is inferred, and it is suggested that Mesozoic sedimentary rocks may lie concealed beneath outer Altafjorden in a half-grabenal structure in the hangingwall of this major fault. Other, small fault-controlled basins containing possible Mesozoic sedimentary rocks may also exist in near-shore areas of western Finnmark.