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Christian Gorini - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Stratigraphy and depositional architecture of Neogene intraslope basins, offshore western Niger Delta
    Marine and Petroleum Geology, 2019
    Co-Authors: Kelvin Chima, Damien Do Couto, Estelle Leroux, Silvia Gardin, Nick Hoggmascall, Marina Rabineau, Didier Granjeon, Christian Gorini
    Abstract:

    Located on a divergent margin dominated by gravity tectonics above overpressured marine shales, the Niger Delta slope has been described as having a stepped profile characterized by ‘filled ponded basins’ that are prone to erosion and sediment bypass. Previous studies based on 3D Seismic data have described the depositional architecture of the western Niger Delta's upper slope, but calibration of the Seismic facies is lacking and the timing of major changes in sedimentary record remains elusive. In this study, Seismic sequence-Stratigraphy, 3D geomorphological analyses of high-resolution 3D Seismic data, and bio/chronostratigraphic analyses from four boreholes, enabled the identification and characterization of the depositional architecture in Neogene ‘filled ponded basins’. Seven major Seismic units were dated as Chattian, Burdigalian, Serravallian, Tortonian, Middle Pliocene and Middle Pleistocene to the present day. Major changes in the sedimentary record occurred in the Plio-Pleistocene, with the onset of erosive channel levee systems (CLSs) and mass-transport deposits (MTDs) generally capped by a hemipelagic drape. Amalgamated CLSs characterize the Tortonian-Late Miocene while erosive MTDs and CLSs characterize the Plio-Pleistocene units. Thick, laterally extensive MTDs are associated with regional slope instability, while active mobile shale triggered local spatially confined MTDs. Submarine channels evolved from moderate to highly sinuous. The degree of channel confinement generally decreases downstream where they are characterized by abandoned meander loops and avulsion resulting from levee breaching. Channel fills and levees/overbank deposits topped by hemipelagic drapes provide effective reservoir/seal (traps) for hydrocarbons. The alternation of channel deposits and hemipelagic layers indicate that eustasy controlled depositional patterns at a regional scale, while the spatio-temporal switches in submarine channel courses show that shale tectonics locally controlled deposition in intraslope basins.

Kelvin Chima - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Stratigraphy and depositional architecture of Neogene intraslope basins, offshore western Niger Delta
    Marine and Petroleum Geology, 2019
    Co-Authors: Kelvin Chima, Damien Do Couto, Estelle Leroux, Silvia Gardin, Nick Hoggmascall, Marina Rabineau, Didier Granjeon, Christian Gorini
    Abstract:

    Located on a divergent margin dominated by gravity tectonics above overpressured marine shales, the Niger Delta slope has been described as having a stepped profile characterized by ‘filled ponded basins’ that are prone to erosion and sediment bypass. Previous studies based on 3D Seismic data have described the depositional architecture of the western Niger Delta's upper slope, but calibration of the Seismic facies is lacking and the timing of major changes in sedimentary record remains elusive. In this study, Seismic sequence-Stratigraphy, 3D geomorphological analyses of high-resolution 3D Seismic data, and bio/chronostratigraphic analyses from four boreholes, enabled the identification and characterization of the depositional architecture in Neogene ‘filled ponded basins’. Seven major Seismic units were dated as Chattian, Burdigalian, Serravallian, Tortonian, Middle Pliocene and Middle Pleistocene to the present day. Major changes in the sedimentary record occurred in the Plio-Pleistocene, with the onset of erosive channel levee systems (CLSs) and mass-transport deposits (MTDs) generally capped by a hemipelagic drape. Amalgamated CLSs characterize the Tortonian-Late Miocene while erosive MTDs and CLSs characterize the Plio-Pleistocene units. Thick, laterally extensive MTDs are associated with regional slope instability, while active mobile shale triggered local spatially confined MTDs. Submarine channels evolved from moderate to highly sinuous. The degree of channel confinement generally decreases downstream where they are characterized by abandoned meander loops and avulsion resulting from levee breaching. Channel fills and levees/overbank deposits topped by hemipelagic drapes provide effective reservoir/seal (traps) for hydrocarbons. The alternation of channel deposits and hemipelagic layers indicate that eustasy controlled depositional patterns at a regional scale, while the spatio-temporal switches in submarine channel courses show that shale tectonics locally controlled deposition in intraslope basins.

Raisson François - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Stratigraphy of Cretaceous eastern Central Atlantic Ocean: Basin evolution and palaeoceanographic implications
    'Elsevier BV', 2018
    Co-Authors: Mourlot Yannick, Calvès Gérôme, Clift Peter, Baby Guillaume, Chaboureau Anne-claire, Raisson François
    Abstract:

    International audienceThe evolution and resulting morphology of a Cretaceous contourite drift in the eastern Central Atlantic oceanic basin is investigated in unprecedented detail using Seismic imaging and age-calibrated cross-margin sections. The margin, from the shelf, slope to deep-water and abyssal plain is constructed by a succession of erosive and depositional mounded structures that relate to bottom-water currents and sediment winnowing. The regional mapping of these drifts, sediment waves and gravitational sedimentary systems allows us to test the Upper Cretaceous paleocirculation model. Combined with flexural backstripping of the regional cross section, it reveals the water-depth range at which the observed sedimentary features occur. A possible late Albian to Turonian contourite drift system is observed from Guinea to Mauritania. The development of a shallow to deep oceanic circulation system is a key element in the rock record, with implications for the palaeoceanography and layering of the Cretaceous ocean. The Cretaceous geological interval and oceanic model mirrors the stratification of the modern ocean and the morphology of its seafloor from offshore Morocco to Guinea

  • Seismic Stratigraphy of Cretaceous eastern Central Atlantic Ocean: Basin evolution and palaeoceanographic implications
    'Elsevier BV', 2018
    Co-Authors: Mourlot Yannick, Calvès Gérôme, Baby Guillaume, Chaboureau Anne-claire, Clift, Peter D., Raisson François
    Abstract:

    Highlights • Morphology and evolution of a Cretaceous contourite drift in the eastern Central Atlantic oceanic basin. • Backstripping of the regional cross section reveals the water-depth range at which the observed sedimentary features occur. • Cretaceous geological interval and oceanic model mirrors the stratification of the Modern Ocean and the morphology of its seafloor. Abstract The evolution and resulting morphology of a Cretaceous contourite drift in the eastern Central Atlantic oceanic basin is investigated in unprecedented detail using Seismic imaging and age-calibrated cross-margin sections. The margin, from the shelf, slope to deep-water and abyssal plain is constructed by a succession of erosive and depositional mounded structures that relate to bottom-water currents and sediment winnowing. The regional mapping of these drifts, sediment waves and gravitational sedimentary systems allows us to test the Upper Cretaceous paleocirculation model. Combined with flexural backstripping of the regional cross section, it reveals the water-depth range at which the observed sedimentary features occur. A possible late Albian to Turonian contourite drift system is observed from Guinea to Mauritania. The development of a shallow to deep oceanic circulation system is a key element in the rock record, with implications for the palaeoceanography and layering of the Cretaceous ocean. The Cretaceous geological interval and oceanic model mirrors the stratification of the modern ocean and the morphology of its seafloor from offshore Morocco to Guinea

Salvatore Passaro - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Stratigraphy of upper quaternary shallow water contourite drifts in the gulf of taranto ionian sea southern italy
    Marine Geology, 2018
    Co-Authors: Fabrizio Pepe, V Di Donato, D D Insinga, F Molisso, C Faraci, Marco Sacchi, R Dera, Luigi Ferranti, Salvatore Passaro
    Abstract:

    Abstract The occurrence of articulated seafloor morphology over continental shelf-upper slope environments, may result in a significant change in the patterns and intensity of basin-scale thermohaline circulation during eustatic sea-level fluctuations. These changes may cause, in turn, erosion, deposition and/or transport of sediments at the seafloor, to form shallow-water contourite drifts. Here we investigate this process in the NW sector of the Gulf of Taranto (Ionian Sea) during and following the Last Glacial Maximum (LGM), by integrating multibeam bathymetric data, ultra-high resolution Seismic-reflection data and gravity core data. Sea level fall caused subaerial exposure of the summit of the Amendolara Bank, forming a short-lived island off the eastern coast of Calabria, and also creating a narrow passageway between the island and the northern Calabria mainland. Integrated Seismic-stratigraphic data show that Upper Quaternary shallow-water contourite drifts and associated erosional features locally formed both around the flanks of the Amendolara Bank (AMBK), and the continental shelf and upper slope off the Amendolara village. Contourite drifts are bounded at the bottom and at the top by two major unconformities, indicating that the formation of the sediments drifts occurred between the onset of the LGM and the GS-1/Younger Dryas event. The stratal architecture suggests the occurrence of various types of contourite deposits, mostly represented by: a) Axial and lateral channel-patch drifts, and channel-related drifts along the incision to the NE of the AMBK; b) Sheeted drifts along the northeastern slope of the AMBK; c) Elongated drifts along the continental shelf and upper slope off the coast of Amendolara village. Erosional features also developed on the south-eastern flank of the AMBK, where the Levantine Intermediate Water flows from the central Ionian Sea towards the Gulf of Taranto, until the present-day. Both processes and timing responsible for erosion of the seafloor and the formation of sediment drifts in the Gulf of Taranto may be similar to that occurred in the Tyrrhenian margins during the Late Quaternary.

Gruetzner Jens - One of the best experts on this subject based on the ideXlab platform.

  • Core-Log-Seismic Integration at ODP Site 909 : Implications for a Revised Stratigraphy of the Central Fram Strait
    2021
    Co-Authors: Gruetzner Jens, Geissler Wolfram, Matthiessen Jens, Gebhardt Catalina, Schreck Michael
    Abstract:

    The Neogene opening and subsequent widening of the only deep-water connection between the Atlantic-Arctic Gateway (AAG) had fundamental influence on global ocean circulation, paleoclimate evolution, and on sedimentation processes in adjacent ocean basins and continental margins. To unravel the evolution of the Fram Strait on tectonic time scales we combined Seismic reflection data with sedimentological and stratigraphic information from ODP Site 909 (Molloy Basin). We derived a higher resolution Seismic Stratigraphy that is based on a revised chronology for Site 909 and an improved core-log-Seismic integration. A revised interpretation of magnetostratigraphic boundaries, shifts previously used stratigraphies for Site 909 to significantly younger ages in the time interval from c. 15 to 3 Ma and allows a more comprehensive correlation with Seismic markers from the western Barents Sea margin and also the adjacent Yermak Plateau

  • A New Seismic Stratigraphy in the Indian-Atlantic Ocean Gateway Resembles Major Paleo-Oceanographic Changes of the Last 7 Ma
    'American Geophysical Union (AGU)', 2020
    Co-Authors: Gruetzner Jens, Jiménez Espejo, Francisco J., Lathika Nambiyathodi, Uenzelmann Neben Gabriele, Hall, Ian R., Levay, Leah J.
    Abstract:

    The exchange of water masses between the Indian Ocean and the Atlantic constitutes an integral interocean link in the global thermohaline circulation. Long-term changes in deep water flow have been studied using Seismic reflection profiles but the Seismic Stratigraphy was poorly constrained and not resolved for the time period from the late Miocene onward. Here we present results from International Ocean Discovery Program Site U1475 (Agulhas Plateau) located over a sediment drift proximal to the entrance of North Atlantic Deep Water into the Southern Ocean and South Indian Ocean. Site U1475 comprises a complete carbonate-rich stratigraphic section of the last ~7 Ma that provides an archive of climate-induced variations in ocean circulation. Six marker reflectors occurring in the upper 300 m of the drift are identified here for the first time. The formation of these reflectors is mainly due to density changes that are mostly caused by changes in biogenic versus terrigenous sediment deposition. Synthetic seismograms allow age assignments for the horizons based on bioStratigraphy and magnetoStratigraphy. Prominent reflectors are related to late Pleistocene glacial/interglacial variability, the middle and early Pleistocene transitions, and the onset of the northern hemisphere glaciation. A peculiar early Pliocene interval (~5.3–4.0 Ma) bounded by two reflectors is characterized by fourfold elevated sedimentation rates (>10 cm/kyr) and the occurrence of sediment waves. We argue that this enhanced sediment transport to the Agulhas Plateau was caused by a reorganization of the bottom current circulation pattern due to maximized inflow of North Atlantic Deep Water.We acknowledge the work of the crew,technicians, and scientific staff of IODPExpedition 361. This research usedsamples and data provided by theInternational Ocean DiscoveryProgram (IODP). Funding wasprovided by the DeutscheForschungsgemeinschaft (DFG) undercontract Ue 49/17. Comments byAndrew Green and an anonymousreviewer greatly improved ourmanuscript. The data reported here areavailable through the Pangaea database(https://doi.org/10.1594/PANGAEA.896810)

  • A New Seismic Stratigraphy in the Indian-Atlantic Ocean Gateway Resembles Major Paleo-Oceanographic Changes of the Last 7 Ma
    'American Geophysical Union (AGU)', 2019
    Co-Authors: Gruetzner Jens, Hines S. K.
    Abstract:

    The exchange of water masses between the Indian Ocean and the Atlantic constitutes an integral interocean link in the global thermohaline circulation. Long‐term changes in deep water flow have been studied using Seismic reflection profiles but the Seismic Stratigraphy was poorly constrained and not resolved for the time period from the late Miocene onward. Here we present results from International Ocean Discovery Program Site U1475 (Agulhas Plateau) located over a sediment drift proximal to the entrance of North Atlantic Deep Water into the Southern Ocean and South Indian Ocean. Site U1475 comprises a complete carbonate‐rich stratigraphic section of the last ~7 Ma that provides an archive of climate‐induced variations in ocean circulation. Six marker reflectors occurring in the upper 300 m of the drift are identified here for the first time. The formation of these reflectors is mainly due to density changes that are mostly caused by changes in biogenic versus terrigenous sediment deposition. Synthetic seismograms allow age assignments for the horizons based on bioStratigraphy and magnetoStratigraphy. Prominent reflectors are related to late Pleistocene glacial/interglacial variability, the middle and early Pleistocene transitions, and the onset of the northern hemisphere glaciation. A peculiar early Pliocene interval (~5.3–4.0 Ma) bounded by two reflectors is characterized by fourfold elevated sedimentation rates (>10 cm/kyr) and the occurrence of sediment waves. We argue that this enhanced sediment transport to the Agulhas Plateau was caused by a reorganization of the bottom current circulation pattern due to maximized inflow of North Atlantic Deep Water