Devonian, orogen-parallel, opposed extension in the Central Norwegian Caledonides

Abstract

Late orogenic, Early to Middle Devonian extension in the Scandinavian Caledonides was unidirectional in western Norway. New data from two detachment zones (Hoybakken and Kollstraumen) north of the More-Trondelag Fault Complex show that bidirectional, opposed, orogen-parallel extension dominated in this region. At this time, the fault complex acted as a transfer zone for the Hoybakken detachment. Extension and uplift in central Norway triggered significant magmatic activity, in contrast to the lack of granite intrusions during exhumation of western Norway.