Magnetotelluric image of a hyper-extended and serpentinized rift system
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 velo...
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Online Access: | http://hdl.handle.net/10852/100527 https://doi.org/10.1016/j.epsl.2022.117914 |
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ftoslouniv:oai:www.duo.uio.no:10852/100527 2023-05-15T15:39:09+02:00 Magnetotelluric image of a hyper-extended and serpentinized rift system ENEngelskEnglishMagnetotelluric image of a hyper-extended and serpentinized rift system Corseri, Romain Planke, Sverre Gelius, Leiv Jacob Faleide, Jan Inge Senger, Kim Abdelmalak, Mohamed Mansour 2023-01-10T10:45:00Z http://hdl.handle.net/10852/100527 https://doi.org/10.1016/j.epsl.2022.117914 EN eng NFR/228107 NFR/308897 NFR/298994 NFR/223272 Corseri, Romain Planke, Sverre Gelius, Leiv Jacob Faleide, Jan Inge Senger, Kim Abdelmalak, Mohamed Mansour . Magnetotelluric image of a hyper-extended and serpentinized rift system. Earth and Planetary Science Letters. 2022, 602 http://hdl.handle.net/10852/100527 2103854 info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Earth and Planetary Science Letters&rft.volume=602&rft.spage=&rft.date=2022 Earth and Planetary Science Letters 602 13 https://doi.org/10.1016/j.epsl.2022.117914 Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ CC-BY 0012-821X VDP::Geofag: 450 Journal article Tidsskriftartikkel Peer reviewed PublishedVersion 2023 ftoslouniv https://doi.org/10.1016/j.epsl.2022.117914 2023-03-01T23:36:42Z 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. Article in Journal/Newspaper Barents Sea Bjørnøya Universitet i Oslo: Digitale utgivelser ved UiO (DUO) Barents Sea Bjørnøya ENVELOPE(-67.250,-67.250,-68.151,-68.151) Earth and Planetary Science Letters 602 117914 |
institution |
Open Polar |
collection |
Universitet i Oslo: Digitale utgivelser ved UiO (DUO) |
op_collection_id |
ftoslouniv |
language |
English |
topic |
VDP::Geofag: 450 |
spellingShingle |
VDP::Geofag: 450 Corseri, Romain Planke, Sverre Gelius, Leiv Jacob Faleide, Jan Inge Senger, Kim Abdelmalak, Mohamed Mansour Magnetotelluric image of a hyper-extended and serpentinized rift system |
topic_facet |
VDP::Geofag: 450 |
description |
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. |
format |
Article in Journal/Newspaper |
author |
Corseri, Romain Planke, Sverre Gelius, Leiv Jacob Faleide, Jan Inge Senger, Kim Abdelmalak, Mohamed Mansour |
author_facet |
Corseri, Romain Planke, Sverre Gelius, Leiv Jacob Faleide, Jan Inge Senger, Kim Abdelmalak, Mohamed Mansour |
author_sort |
Corseri, Romain |
title |
Magnetotelluric image of a hyper-extended and serpentinized rift system |
title_short |
Magnetotelluric image of a hyper-extended and serpentinized rift system |
title_full |
Magnetotelluric image of a hyper-extended and serpentinized rift system |
title_fullStr |
Magnetotelluric image of a hyper-extended and serpentinized rift system |
title_full_unstemmed |
Magnetotelluric image of a hyper-extended and serpentinized rift system |
title_sort |
magnetotelluric image of a hyper-extended and serpentinized rift system |
publishDate |
2023 |
url |
http://hdl.handle.net/10852/100527 https://doi.org/10.1016/j.epsl.2022.117914 |
long_lat |
ENVELOPE(-67.250,-67.250,-68.151,-68.151) |
geographic |
Barents Sea Bjørnøya |
geographic_facet |
Barents Sea Bjørnøya |
genre |
Barents Sea Bjørnøya |
genre_facet |
Barents Sea Bjørnøya |
op_source |
0012-821X |
op_relation |
NFR/228107 NFR/308897 NFR/298994 NFR/223272 Corseri, Romain Planke, Sverre Gelius, Leiv Jacob Faleide, Jan Inge Senger, Kim Abdelmalak, Mohamed Mansour . Magnetotelluric image of a hyper-extended and serpentinized rift system. Earth and Planetary Science Letters. 2022, 602 http://hdl.handle.net/10852/100527 2103854 info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Earth and Planetary Science Letters&rft.volume=602&rft.spage=&rft.date=2022 Earth and Planetary Science Letters 602 13 https://doi.org/10.1016/j.epsl.2022.117914 |
op_rights |
Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.epsl.2022.117914 |
container_title |
Earth and Planetary Science Letters |
container_volume |
602 |
container_start_page |
117914 |
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1766370596701077504 |