Journal of Structural Geology: The tectonized central peak of the Mjølnir Impact Crater, Barents Sea

Romain Corseria, Sébastien Gacb, Jan Inge Faleideb,c, Sverre Plankea,b,c are the authors of the paper “The tectonized central peak of the Mjølnir Impact Crater, Barents Sea” published in Journal of Structural Geology.

aVolcanic Basin Petroleum Research AS, Oslo Science Park, Gaustadalléen 21, N-0349, Oslo, Norway
bCentre for Earth Evolution and Dynamics, Department of Geosciences, University of Oslo, Box 1028 Blindern, 0315, Oslo, Norway
cResearch Centre for Arctic Petroleum Exploration, University of Tromsø, Tromsø, Norway

Abstract

The Mjølnir structure, SW Barents Sea, is one of the best-preserved marine impact craters on Earth. After impact on the paleo-seafloor about 142 Ma ago, this crater experienced an atypical deformation of its central peak, which is now elevated ~435 m above the crater rims. Here, we investigate the effect of far-field tectonic stresses on the central peak uplift based on interpretation of new high-resolution P-Cable and conventional seismic reflection data. Nearby wells provided stratigraphic control on the interpreted horizons. The reconstruction of the crater sedimentary infill supports a subdued original central peak relief with a 5 km-wide, gentle mound ~15 m below the rim. Our interpretation shows that subvertical, outward-dipping, impact-induced faults were reactivated by uplifted segments of the central peak up to 500 m above the platform level during one or several contractional episodes. We postulate that post-Albian tectonic compressional events triggered the structural uplift of the Mjølnir central peak. Differential compaction, previously seen as the main deformation process, may have increased the original central peak height by only ~10 m. The mobilization of impact-shattered rocks by tectonic compression provides a new and robust explanation for the structural rise of Mjølnir’s central peak.

Keywords

Impact crater, Mjølnir impact crater, Central peak, Post-impact modification, Tectonic reactivation Compression

Reference

Corseri, R., Gac, S., Faleide, J. I., Planke, S. The tectonized central peak of the Mjølnir Impact Crater, Barents Sea. Journal of Structural Geology,Volume 131,2020. DOI: 10.1016/j.jsg.2019.103953. [intranet]