Meta‐analysis of the long‐term stratigraphic evolution of rifted margin basins: The GeoDyNamical Analysis approach applied to the South Atlantic Ocean

• Published in: Basin Research
• Main Authors: Laspatzis, Sophie, Rouby, Delphine, Rohais, Sébastien, Nardin, Élise
• Other Authors: IFP Energies nouvelles (IFPEN), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: crustal necking; rifted margin; sedimentary basin; South Atlantic Ocean; stratigraphic architecture; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
• Online Access: https://ifp.hal.science/hal-04179990; https://ifp.hal.science/hal-04179990/document; https://ifp.hal.science/hal-04179990/file/Meta-analysis%20of%20the%20long-term%20stratigraphic%20evolution%20of%20rifted%20margin%20basins.pdf; https://doi.org/10.1111/bre.12740

International audience Models of the formation of rifted margins have significantly evolved over the lastdecades by identifying new styles of crustal thinning and magmatic production.However, the expression of these different processes in the depositional environments of the overlying basins remains to be determined. Using only published data, we integrated the sedimentary evolution of 21 basins of the Equatorial, Central and South segments of the South Atlantic that record various styles of crustal thinning and magmatic production. To compare these basins that underwent rifting at different times, we developed a new type of analysis allowing to evaluate statistically the (dis)similarities in depositional environment trends by normalizing them to the tectonic phases of the basin (syn-rift, transition and post-rift) rather than the stratigraphic or absolute ages: The GeoDyNamical Analysis. We show that the timing of the long-term retrograding mega-sequence driven by lithosphere thinning depends on the deformation style and magma production. Along oblique margins of the Equatorial Segment, deepening initiated during syn-rift because their narrow crustal thinning style favours rapid tectonic subsidence surpassing sediment supply. Along wide margins of the Central Segment, deepening is initiated later, at the end of the transition phase, because depth-dependent thinning favours slow tectonic subsidence and late break-up.Along magma-rich margins of the South Segment, deepening is initiated during the transition phase, after volcanics stopped filling accommodation created by subsidence. In the Central Segment, evaporites accumulated during the second half of the transition phase, when crustal thinning ceased in the proximal margin and migrated to its distal part. Immediately before and during evaporites accumulation, sediments recorded continental and coastal depositional environments resulting from the limited thermal subsidence in the proximal margin domain. Evaporite deposition lasted until the initiation of ...