Formation of intracratonic basins by lithospheric shortening and phase changes: a case study from the ultra‐deep East Barents Sea basin |
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| Authors: | Sébastien Gac Ritske S Huismans Nina S C Simon Yuri Y Podladchikov Jan Inge Faleide |
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| Institution: | 1. Department of Earth Science, University of Bergen, , Bergen, 5007 Norway;2. Institute for Energy Technology, , Kjeller, 2027 Norway;3. Institute of Geophysics, UNIL, , Lausanne, CH‐1015 Switzerland;4. Department of Geosciences, University of Oslo, , Oslo, 0316 Norway |
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| Abstract: | The origin of large subsidence in intracratonic basins is still under debate. We propose a new and self‐consistent model for the formation of those basins, where lithospheric shortening/buckling triggers metamorphism and densification of crustal mafic heterogeneities. We use a forward thermo‐mechanical finite element technique to evaluate this mechanism for the typical example of the East Barents Sea basin (EBB) where a very large and compensated subsidence, accommodating an up to 20‐km‐thick sediment succession, is observed. The lower crust in the dynamic model is modelled with petrologic‐consistent densities for a wet mafic gabbroic composition that depend on pressure and temperature taking into account dehydration at high PT conditions. The model successfully explains the main characteristics of the EBB, notably the large anomalous and fast subsidence during the Late Permian–Early Triassic, its present‐day geometry and the absence of a significant gravity anomaly. |
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