Romain Corseri

• Corseri, Romain; Planke, Sverre; Gelius, Leiv Jacob; Faleide, Jan Inge; Senger, Kim & Abdelmalak, Mohamed Mansour (2022). Magnetotelluric image of a hyper-extended and serpentinized rift system. Earth and Planetary Science Letters. ISSN 0012-821X. 602. doi: 10.1016/j.epsl.2022.117914. Full text in Research Archive Show summary

  Magnetotelluric (MT) data can image the Earth's electrical resistivity down to the mantle but are rarely used for investigation of offshore rifted margins. In such settings, the lower crust and upper mantle are altered by distinct tectono-thermal processes but often display similar seismic velocities and densities. By integrating resistivity models from MT data, we aim at resolving such ambiguity. Here, 3D inversion of long period, marine MT data (1 – 3000 s) is performed on 104 receivers located along two, ∼300 km long transects in the SW Barents Sea. The resolving power of MT data is assessed with synthetic tests in an archetypal rift system where ample crustal thickness variation occurs. The results highlight that our MT data sense the transition from necking to hyper-extended domain where the crust (<10 km) is not recovered by 3D inversion. In the Bjørnøya Basin – the northernmost member of a hyper-extended Cretaceous basin chain in the NE Atlantic – we combine seismic interpretation and MT inversion models to assign resistivity properties at two depth intervals: (1) 0.1-1 Ωm within Lower Cretaceous marine shales buried at 10-15 km depth (2) 1-10 Ωm within the uppermost mantle. Based on a fluid-rock model, we emphasize that seawater as a sole pore fluid phase is not conductive enough to explain such high bulk conductivities at both intervals. A 25% serpentinization of mantle rocks can account for a fivefold rise in salinity of the residual fluid and is compatible with bulk resistivity, density, and seismic velocities in the Bjørnøya Basin. Such high-salinity fluid can ascend and mix with seawater in pore spaces of the sediments, supporting our model of saline fluid circulation in hyper-extended basins. In conclusion, electrical resistivity models can disambiguate interpretation of deep structures in rifted margin by detecting saline fluids from partial serpentinization, intermixing with seawater in overlying marine sediments.

• Corseri, Romain; Planke, Sverre; Faleide, Jan Inge; Senger, Kim; Gelius, Leiv-J. & Johansen, Ståle Emil (2021). Opportunistic magnetotelluric transects from CSEM surveys in the Barents Sea. Geophysical Journal International. ISSN 0956-540X. 227(3), p. 1832–1845. doi: 10.1093/gji/ggab312.
• Corseri, Romain; Gac, Sebastien; Faleide, Jan Inge & Planke, Sverre (2020). The tectonized central peak of the Mjølnir Impact Crater, Barents Sea. Journal of Structural Geology. ISSN 0191-8141. 131. doi: 10.1016/j.jsg.2019.103953. Full text in Research Archive Show summary

  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.

• Corseri, Romain; Faleide, Thea Sveva; Faleide, Jan Inge; Midtkandal, Ivar; Serck, C.S & Trulsvik, Mikal [Show all 7 contributors for this article] (2018). A diverted submarine channel of Early Cretaceous age revealed by high-resolution seismic data, SW Barents Sea. Marine and Petroleum Geology. ISSN 0264-8172. 98, p. 462–476. doi: 10.1016/j.marpetgeo.2018.08.037.
• Corseri, Romain; Senger, Kim; Selway, Katherine; Abdelmalak, Mohamed Mansour; Planke, Sverre & Jerram, Dougal Alexander (2017). Magnetotelluric evidence for massive sulphide mineralization in intruded sediments of the outer Vøring Basin, mid-Norway. Tectonophysics. ISSN 0040-1951. doi: 10.1016/j.tecto.2017.04.011.

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