The post-Devonian tectonic evolution of southern Spitsbergen illustrated by structural cross-sections through Bellsund and Hornsund

Construction of cross-sections in Bellsund and Hornsund, southern Spitsbergen, using offshore and onshore structural data illustrate the main tectonic units of the region. From west to east these are: a wedge of late Cenozoic clastic sediments; a series of late Palaeozoic to early Mesozoic grabens controlled by basement faults along the west Spitsbergen margin; the Basement Horst, comprising late Precambrian to early Palaeozoic rocks deformed and metamorphosed during a mid- Palaeozoic orogeny; the Fold Belt, which forms a narrow NNW-SSE striking zone of eastward verging folds and thrusts attributed to Eocene inversion of a pre-Cenozoic basin; the Palaeogene Central Basin, deformed into a broad synclinorium and bound to the east by the Billefjorden Fault Zone. This basement lineament shows evidence of Palaeogene reactivation and may be linked to the Fold Belt by a detachment zone beneath the Central Basin. East of Spitsbergen, there is an offshore basin of possible Carboniferous age controlled by the Storfjorden Fault Zone which shows evidence of later inversion to form a positive flower structure.