Joint inversion of receiver functions and surface wave dispersion in the Reconcavo-Tucano basin of NE Brazil: implications for basin formation
The crustal structure of the Reconcavo-Tucano basin, an aborted rift system that developed in NE Brazil during extension related to the opening of the South Atlantic Ocean, has been investigated through local constraints from receiver functions developed at 18 seismic stations in the region. Gravity...
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Oxford Univ Press
2022
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Online Access: | https://archimer.ifremer.fr/doc/00763/87522/93018.pdf https://archimer.ifremer.fr/doc/00763/87522/93019.pdf https://doi.org/10.1093/gji/ggac080 https://archimer.ifremer.fr/doc/00763/87522/ |
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ftarchimer:oai:archimer.ifremer.fr:87522 2023-05-15T18:21:19+02:00 Joint inversion of receiver functions and surface wave dispersion in the Reconcavo-Tucano basin of NE Brazil: implications for basin formation Doring, M. F. Julia, J. Evain, Mikael 2022-03 application/pdf https://archimer.ifremer.fr/doc/00763/87522/93018.pdf https://archimer.ifremer.fr/doc/00763/87522/93019.pdf https://doi.org/10.1093/gji/ggac080 https://archimer.ifremer.fr/doc/00763/87522/ eng eng Oxford Univ Press https://archimer.ifremer.fr/doc/00763/87522/93018.pdf https://archimer.ifremer.fr/doc/00763/87522/93019.pdf doi:10.1093/gji/ggac080 https://archimer.ifremer.fr/doc/00763/87522/ info:eu-repo/semantics/openAccess restricted use Geophysical Journal International (0956-540X) (Oxford Univ Press), 2022-03 , Vol. 230 , N. 1 , P. 317-333 South America Joint Inversion Crustal imaging Continental tectonics: extensional text Publication info:eu-repo/semantics/article 2022 ftarchimer https://doi.org/10.1093/gji/ggac080 2022-04-12T22:50:04Z The crustal structure of the Reconcavo-Tucano basin, an aborted rift system that developed in NE Brazil during extension related to the opening of the South Atlantic Ocean, has been investigated through local constraints from receiver functions developed at 18 seismic stations in the region. Gravity modelling has proved unable to unequivocally localize crustal thinning under the basin depocentre and, together with a general lack of sediments from a putative thermal sag phase, this has led to a range of basin formation models invoking either pure or simple shear or a combination of both. In particular, the 'flexural cantilever' model has assumed simple shear extension in the upper crust and pure shear extension in the lower crust and mantle, enabling local erosion of the rift flanks after footwall uplift and regional erosion of the thermal sag phase after magmatic underplate of the basin's crust. Our results reveal that the crust is over 40 km thick beneath the Tucano and Reconcavo basins and that it contains a thick (5-8 km) layer of high velocity (Vs > 4.0 km s(-1)) material below similar to 35 km depth. These observations contrast with structure immediately West (Sao Francisco Craton) and East (Borborema Province) of the basin, for which crustal thicknesses average 42 and 36 km, respectively, lower crustal velocities are below 4.0 km s(-1), and local instances of crust as thin as 33.5 km are observed. We propose, in agreement with the 'flexural cantilever' model, that the fast velocity layer making the basin's lowermost crust resulted from mafic underplating after stretching and thinning during the syn-rift phase, restoring crustal thickness to pre-rift values (or larger) and providing the necessary buoyancy to trigger regional uplift. Moreover, although not pervasive, instances of thin crust along the footwall could be related to rift flank erosion. We thus conclude that, regardless of the mode of extension in the upper crust, our results favour models of basin formation invoking extension of the lower crust by pure shear. Article in Journal/Newspaper South Atlantic Ocean Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Geophysical Journal International 230 1 317 333 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
topic |
South America Joint Inversion Crustal imaging Continental tectonics: extensional |
spellingShingle |
South America Joint Inversion Crustal imaging Continental tectonics: extensional Doring, M. F. Julia, J. Evain, Mikael Joint inversion of receiver functions and surface wave dispersion in the Reconcavo-Tucano basin of NE Brazil: implications for basin formation |
topic_facet |
South America Joint Inversion Crustal imaging Continental tectonics: extensional |
description |
The crustal structure of the Reconcavo-Tucano basin, an aborted rift system that developed in NE Brazil during extension related to the opening of the South Atlantic Ocean, has been investigated through local constraints from receiver functions developed at 18 seismic stations in the region. Gravity modelling has proved unable to unequivocally localize crustal thinning under the basin depocentre and, together with a general lack of sediments from a putative thermal sag phase, this has led to a range of basin formation models invoking either pure or simple shear or a combination of both. In particular, the 'flexural cantilever' model has assumed simple shear extension in the upper crust and pure shear extension in the lower crust and mantle, enabling local erosion of the rift flanks after footwall uplift and regional erosion of the thermal sag phase after magmatic underplate of the basin's crust. Our results reveal that the crust is over 40 km thick beneath the Tucano and Reconcavo basins and that it contains a thick (5-8 km) layer of high velocity (Vs > 4.0 km s(-1)) material below similar to 35 km depth. These observations contrast with structure immediately West (Sao Francisco Craton) and East (Borborema Province) of the basin, for which crustal thicknesses average 42 and 36 km, respectively, lower crustal velocities are below 4.0 km s(-1), and local instances of crust as thin as 33.5 km are observed. We propose, in agreement with the 'flexural cantilever' model, that the fast velocity layer making the basin's lowermost crust resulted from mafic underplating after stretching and thinning during the syn-rift phase, restoring crustal thickness to pre-rift values (or larger) and providing the necessary buoyancy to trigger regional uplift. Moreover, although not pervasive, instances of thin crust along the footwall could be related to rift flank erosion. We thus conclude that, regardless of the mode of extension in the upper crust, our results favour models of basin formation invoking extension of the lower crust by pure shear. |
format |
Article in Journal/Newspaper |
author |
Doring, M. F. Julia, J. Evain, Mikael |
author_facet |
Doring, M. F. Julia, J. Evain, Mikael |
author_sort |
Doring, M. F. |
title |
Joint inversion of receiver functions and surface wave dispersion in the Reconcavo-Tucano basin of NE Brazil: implications for basin formation |
title_short |
Joint inversion of receiver functions and surface wave dispersion in the Reconcavo-Tucano basin of NE Brazil: implications for basin formation |
title_full |
Joint inversion of receiver functions and surface wave dispersion in the Reconcavo-Tucano basin of NE Brazil: implications for basin formation |
title_fullStr |
Joint inversion of receiver functions and surface wave dispersion in the Reconcavo-Tucano basin of NE Brazil: implications for basin formation |
title_full_unstemmed |
Joint inversion of receiver functions and surface wave dispersion in the Reconcavo-Tucano basin of NE Brazil: implications for basin formation |
title_sort |
joint inversion of receiver functions and surface wave dispersion in the reconcavo-tucano basin of ne brazil: implications for basin formation |
publisher |
Oxford Univ Press |
publishDate |
2022 |
url |
https://archimer.ifremer.fr/doc/00763/87522/93018.pdf https://archimer.ifremer.fr/doc/00763/87522/93019.pdf https://doi.org/10.1093/gji/ggac080 https://archimer.ifremer.fr/doc/00763/87522/ |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_source |
Geophysical Journal International (0956-540X) (Oxford Univ Press), 2022-03 , Vol. 230 , N. 1 , P. 317-333 |
op_relation |
https://archimer.ifremer.fr/doc/00763/87522/93018.pdf https://archimer.ifremer.fr/doc/00763/87522/93019.pdf doi:10.1093/gji/ggac080 https://archimer.ifremer.fr/doc/00763/87522/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.1093/gji/ggac080 |
container_title |
Geophysical Journal International |
container_volume |
230 |
container_issue |
1 |
container_start_page |
317 |
op_container_end_page |
333 |
_version_ |
1766200522040147968 |