Constraints on the Magnitude and Timing of Cenozoic Exhumation for the Russian Barents Sea

The regional Late Cretaceous-Cenozoic exhumation event is rather poor investigated for the Russian part of the Barents Sea. Recently interpretation of existing offshore well logs for the Russian Barents Sea was performed and generalized porosity-depth trends were compiled (Sobolev, 2012). The results of porosity-depth analysis were supplemented with sonic log interpretation and vitrinite reflectance data to provide assessment of the total Mesozoic-Cenozoic exhumation magnitude. In this study we extended the latter approach to interpolate the results from wells using seismic velocity data from common-depth point seismic reflection surveys. The previous point assessments of the regional Cenozoic exhumation magnitude were significantly improved. Differential exhumation throughout the province has occurred. The least uplift and erosion (400-500 m) occur in the depocenters of both South and North Barents Sea Basins. The combined fission-track and U/Pb dating of apatite by LA-ICP-MS was used for reconstruction of the thermal history. The apatite from all 13 samples (Fersmanovskaya-1 well) was dated is partially annealed. The tentative interpretation of fission-track data shows that the Lower Triassic – Lower Jurassic rocks, apparently, used to be within the partial annealing zone in Middle Jurassic - Cretaceous, and an acceleration of exhumation occurred in Early Paleogene (~60 Ma).