Utsira transect

Low-temperature thermochronology is a powerful tool to reconstruct processes in the upper crust, such as exhumation, faulting and burial histories in sedimentary basins. In the absence of an onshore sedimentary record, a combination of fission track, (U-Th)/He and K/Ar dating has proven invaluable to investigate the post-Caledonian tectonic history of the Norwegian margin, for example in the Bergen area.

However, from areas south of the Hardangerfjord, the coastal section directly opposite the Johan Sverdrup field, virtually no thermochronological data are available. Therefore we propose an in-depth thermochronological study of a transect from the Viking Graben across the Utsira High and Haugesund area to the Hardangervidda, combining fission track, (U-Th)/He, K/Ar and U/Pb dating.

Along this transect, the Norwegian margin is dissected by both coast-parallel faults and major crustal lineaments such as the Hardangerfjord Shear Zone. Offshore these faults play a significant role in the development of the North Sea sedimentary basins and basement highs, onshore they exert control on the rift shoulder topography and landscape development. Especially onshore, the age and history of reactivation of many faults are poorly understood. Dating periods of movements along these faults is therefore an essential part of unravelling the tectonic history of the Norwegian margin and can help to refine the onset of rifting, main rift stages and the width of the North Sea rift system.

Scholar: Anna K. Ksienzyk

Project directors: Joachim Jacobs and Haakon Fossen, UiB

Project funding: VISTA

Project duration: 1. November 2012 – 31. October 2015