Basin modelling of the SW Barents Sea. (August 2018) - Gac, Sébastien
Abstract: The SW Barents Sea is an epicontinental platform consisting of N- to NNE-oriented basins separated by basement highs. The basins were formed during four distinct rift-phases in the Carboniferous, Late Permian, Late Jurassic-Early Cretaceous, and Paleocene-Eocene. Progressive rifting culminated in continental breakup and seafloor spreading along the North Atlantic axis approximately at 55 Ma. We present tectonic and thermal models of basin evolution along two seismic profiles crossing the SW Barents Sea. The thermal and isostatic history of basins is constrained through time-forward basin modelling based on an automated inverse basin reconstruction approach. We estimate the effects of continental breakup and near-margin processes (magmatic underplating and sill intrusions) on the thermal history and kerogen maturity below the Vestbakken Volcanic Province. Basin models are calibrated against well data. The results imply that both breakup and underplating alter the thermal and isostatic history of sediments along the margin. The hydrocarbon potential of source rocks modelled along the margin suggests breakup has a permanent thermal effect on the present-day sediments promoted by lateral heat flow, while heat conduction by underplating is more diffuse, inhibited to some degree by deeply-buried, low-conductivity shales and limestones. Highlights: The tectono-thermal evolution of SW Barents Sea sedimentary basins is modelled. The effects of near-margin processes on maturity of source rocks are simulated. Continental breakup has a permanent effect on the maturation of source rocks. Magmatic underplating has a transient effect on the maturation of source rocks.