Effect of lithosphere thickness heterogeneities in controlling rift localization: Numerical modeling of the Oslo Graben

We present 2-D thermo-mechanical and numerical modeling at lithospheric scale to assess the impact of pre-existing lithosphere thickness contrast on rift localization. The results of the modeling suggest that thickness heterogeneity was responsible for focussing rifting and passive asthenospheric upwelling in the Permo-Carboniferous Oslo Graben at the western margin of the Fennoscandian Shield. These findings are consistent with inferences from recent studies showing that both the crustmantle boundary and the base of the lithosphere are and were deeper at the eastern margin of the Oslo Graben, resulting in contrasting crust and lithosphere thickness.