The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Benjamin Corre - One of the best experts on this subject based on the ideXlab platform.
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Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn‐rift salt tectonics
Basin Research, 2020Co-Authors: Thibault Duretz, Riccardo Asti, Yves Lagabrielle, Jeanpierre Brun, Anthony Jourdon, Camille Clerc, Benjamin CorreAbstract:The preshortening Cretaceous Pyrenean Rift is an outstanding geological laboratory to investigate the effects of a pre‐rift salt layer at the sedimentary base on lithospheric Rifting. The occurrence of a pre‐rift km‐scale layer of evaporites and shales promoted the activation of syn‐rift salt tectonics from the onset of Rifting. The pre‐ and syn‐rift sediments are locally affected by high‐temperature metamorphism related to mantle ascent up to shallow depths during Rifting. The thermo‐mechanical interaction between décollement along the pre‐existing salt layer and mantle ascent makes the Cretaceous Pyrenean Rifting drastically different from the type of Rifting that shaped most Atlantic‐type passive margins where salt deposition is syn‐rift and gravity‐driven salt tectonics has been postrift. To unravel the dynamic evolution of the Cretaceous Pyrenean Rift, we carried out a set of numerical models of lithosphere‐scale extension, calibrated using the available geological constraints. Models are used to investigate the effects of a km‐scale pre‐rift salt layer, located at the sedimentary cover base, on the dynamics of Rifting. Our results highlight the key role of the décollement layer at cover base that can alone explain both salt tectonics deformation style and high‐temperature metamorphism of the pre‐rift and syn‐rift sedimentary cover. On the other hand, in the absence of décollement, our model predicts symmetric necking of the lithosphere devoid of any structure and related thermal regime geologically relevant to the Pyrenean case.
Victor Ramos - One of the best experts on this subject based on the ideXlab platform.
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Mesozoic Rifting evolution of SW Gondwana: a poly-phased, subduction- related, extensional history responsible for basin formation along the Argentinean Atlantic margin
Earth-Science Reviews, 2020Co-Authors: Juan Pablo Lovecchio, Sébastien Rohais, Philippe Joseph, Néstor Bolatti, Victor RamosAbstract:The opening of the South Atlantic in the Early Cretaceous was the final stage of the complex Rifting history of SW Gondwana. In this contribution we reassess the chronology of Mesozoic basin formation in southern South America and Africa and integrate it in the long-term breakup history of SW Gondwana. Triassic Rifting is characterized by intracontinental Rifting in Africa (Karoo I phase), and retro-arc extension on the SW-margin of Gondwana. In the Early Jurassic, the impingement of the Karoo plume triggered Rifting in Eastern Africa, producing the Karoo II basins (and the Colorado and Salado basins on the Argentinean shelf). East Africa Rifting ultimately lead the breakup of Eastern from Western Gondwana in the Middle Jurassic. In Patagonia, the Austral, Malvinas and other related basins formed in association with the synextensional emplacement of the Chon Aike magmatic province in the Patagonian retro-arc. In the Late Jurassic the Rocas Verdes back-arc basin opened in southern Patagonia, while oblique Rifting in the core of the Late J o u r n a l P r e-p r o o f Journal Pre-proof 2 Paleozoic Gondwanides orogen produced the Outeniqua and Rawson/Valdés basins. The South Atlantic Rift initiated in the Early Cretaceous associated with present-day E-W extension. Rifting occurred diachronically from south to north, initiating in the previously thinned Rawson/Valdés-Outeniqua segment. A precursor oblique rift system and a larger degree of extension in this segment could explain the lack of Seaward Dipping Reflectors (SDR) south of the Colorado-Cape fracture zones. Rifting and SDR emplacement occurred progressively to the north along different rift segments, producing strongly asymmetric conjugate margins.
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Multistage Rifting evolution of the Colorado basin (offshore Argentina): Evidence for extensional settings prior to the South Atlantic opening
Terra Nova, 2018Co-Authors: Juan Pablo Lovecchio, Sébastien Rohais, Philippe Joseph, Néstor Bolatti, Pedro Kress, Ricardo Gerster, Victor RamosAbstract:The identification of three independent Rifting events in the Colorado basin area highlights the complexity of its Mesozoic Rifting history, which ended in the Early Cretaceous with the opening of the South Atlantic Ocean. A first Rifting event, associated with the extensional reactivation of previously compressive thrusts of the Ventania‐Cape fold belt, is transected by faults forming the main depocenters of the Colorado and possibly the adjacent Salado basin. The second and main Rifting stage is correlated with the Early Jurassic Karoo Rifting. In the Early Cretaceous, WNW–ESE extension produced NNE‐trending landward‐dipping faults, concentrated in the outer 100–200 km of the continental crust domain, possibly coeval with SDR emplacement. This is the first identification of three superimposed Rifting settings in the southern South Atlantic realm and is key to understanding the complex Mesozoic breakup history of SW Gondwana.
Jeanpierre Brun - One of the best experts on this subject based on the ideXlab platform.
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Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn‐rift salt tectonics
Basin Research, 2020Co-Authors: Thibault Duretz, Riccardo Asti, Yves Lagabrielle, Jeanpierre Brun, Anthony Jourdon, Camille Clerc, Benjamin CorreAbstract:The preshortening Cretaceous Pyrenean Rift is an outstanding geological laboratory to investigate the effects of a pre‐rift salt layer at the sedimentary base on lithospheric Rifting. The occurrence of a pre‐rift km‐scale layer of evaporites and shales promoted the activation of syn‐rift salt tectonics from the onset of Rifting. The pre‐ and syn‐rift sediments are locally affected by high‐temperature metamorphism related to mantle ascent up to shallow depths during Rifting. The thermo‐mechanical interaction between décollement along the pre‐existing salt layer and mantle ascent makes the Cretaceous Pyrenean Rifting drastically different from the type of Rifting that shaped most Atlantic‐type passive margins where salt deposition is syn‐rift and gravity‐driven salt tectonics has been postrift. To unravel the dynamic evolution of the Cretaceous Pyrenean Rift, we carried out a set of numerical models of lithosphere‐scale extension, calibrated using the available geological constraints. Models are used to investigate the effects of a km‐scale pre‐rift salt layer, located at the sedimentary cover base, on the dynamics of Rifting. Our results highlight the key role of the décollement layer at cover base that can alone explain both salt tectonics deformation style and high‐temperature metamorphism of the pre‐rift and syn‐rift sedimentary cover. On the other hand, in the absence of décollement, our model predicts symmetric necking of the lithosphere devoid of any structure and related thermal regime geologically relevant to the Pyrenean case.
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Continental Rifting as a function of lithosphere mantle strength
Tectonophysics, 2008Co-Authors: Frédéric Gueydan, Christina Morency, Jeanpierre BrunAbstract:The role of the uppermost mantle strength in the pattern of lithosphere Rifting is investigated using a thermo-mechanical finite-element code. In the lithosphere, the mantle/crust strength ratio (SM/SC) that decreases with increasing Moho temperature TM allows two strength regimes to be defined: mantle dominated (SM > SC) and crust dominated (SM < SC). The transition between the two regimes corresponds to the disappearance of a high strength uppermost mantle for TM > 700 °C. 2D numerical simulations for different values of SM/SC show how the uppermost mantle strength controls the style of continental Rifting. A high strength mantle leads to strain localisation at lithosphere scale, with two main patterns of narrow Rifting: "coupled crustmantle" at the lowest TM values and "deep crustal décollement" for increasing TM values, typical of some continental rifts and non-volcanic passive margins. The absence of a high strength mantle leads to distributed deformations and wide Rifting in the upper crust. These numerical results are compared and discussed in relation with series of classical rift examples.
Juan Pablo Lovecchio - One of the best experts on this subject based on the ideXlab platform.
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Mesozoic Rifting evolution of SW Gondwana: a poly-phased, subduction- related, extensional history responsible for basin formation along the Argentinean Atlantic margin
Earth-Science Reviews, 2020Co-Authors: Juan Pablo Lovecchio, Sébastien Rohais, Philippe Joseph, Néstor Bolatti, Victor RamosAbstract:The opening of the South Atlantic in the Early Cretaceous was the final stage of the complex Rifting history of SW Gondwana. In this contribution we reassess the chronology of Mesozoic basin formation in southern South America and Africa and integrate it in the long-term breakup history of SW Gondwana. Triassic Rifting is characterized by intracontinental Rifting in Africa (Karoo I phase), and retro-arc extension on the SW-margin of Gondwana. In the Early Jurassic, the impingement of the Karoo plume triggered Rifting in Eastern Africa, producing the Karoo II basins (and the Colorado and Salado basins on the Argentinean shelf). East Africa Rifting ultimately lead the breakup of Eastern from Western Gondwana in the Middle Jurassic. In Patagonia, the Austral, Malvinas and other related basins formed in association with the synextensional emplacement of the Chon Aike magmatic province in the Patagonian retro-arc. In the Late Jurassic the Rocas Verdes back-arc basin opened in southern Patagonia, while oblique Rifting in the core of the Late J o u r n a l P r e-p r o o f Journal Pre-proof 2 Paleozoic Gondwanides orogen produced the Outeniqua and Rawson/Valdés basins. The South Atlantic Rift initiated in the Early Cretaceous associated with present-day E-W extension. Rifting occurred diachronically from south to north, initiating in the previously thinned Rawson/Valdés-Outeniqua segment. A precursor oblique rift system and a larger degree of extension in this segment could explain the lack of Seaward Dipping Reflectors (SDR) south of the Colorado-Cape fracture zones. Rifting and SDR emplacement occurred progressively to the north along different rift segments, producing strongly asymmetric conjugate margins.
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Seismic stratigraphy of the offshore basins of Argentina : characterization and modeling of the South Atlantic passive margin dynamics
2018Co-Authors: Juan Pablo LovecchioAbstract:This work is focused on basin formation and evolution in the Argentinean South Atlantic Margin and the Mesozoic breakup of SW Gondwana. Rifting evolution was studied in the Malvinas and Colorado/Salado basins. Three superimposed Rifting events were identified in the latter. The first Rifting event is associated with the Late Triassic extensional reactivation of Late Paleozoic thrusts of the Ventania-Cape fold belt. A second and main Rifting stage (Early-Middle Jurassic) is related to faults forming the main depocenters and intersecting the older structures. Finally, Early Cretaceous extension linked to the opening of the South Atlantic Ocean focused on the outer continental fringe and produced emplacement of SDRs. The Rifting evolution of the Malvinas basin was seismically characterized. New zircon U-Pb ages constrain Rifting in the Jurassic. A new model for Gondwana breakup is presented with focus on the evolution of the Mesozoic peri-Atlantic basins. The post-breakup evolution of the Argentinean South Atlantic margin was also studied via seismic interpretation and stratigraphic characterization. Three stages of drift evolution were identified. After the Hauterivian/Barremian breakup, the Cretaceous drift unit is conditioned by the thermal subsidence over the main depocenters. Only after the Maastrichtian-Danian regional transgression, the margin becomes a single continental platform. The Paleogene drift stage is characterized by subsidence and sedimentary input centered in the Salado area, while the Neogene drift stage is characterized by a cylindrical behavior and the remarkable influence of contour currents.
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Multistage Rifting evolution of the Colorado basin (offshore Argentina): Evidence for extensional settings prior to the South Atlantic opening
Terra Nova, 2018Co-Authors: Juan Pablo Lovecchio, Sébastien Rohais, Philippe Joseph, Néstor Bolatti, Pedro Kress, Ricardo Gerster, Victor RamosAbstract:The identification of three independent Rifting events in the Colorado basin area highlights the complexity of its Mesozoic Rifting history, which ended in the Early Cretaceous with the opening of the South Atlantic Ocean. A first Rifting event, associated with the extensional reactivation of previously compressive thrusts of the Ventania‐Cape fold belt, is transected by faults forming the main depocenters of the Colorado and possibly the adjacent Salado basin. The second and main Rifting stage is correlated with the Early Jurassic Karoo Rifting. In the Early Cretaceous, WNW–ESE extension produced NNE‐trending landward‐dipping faults, concentrated in the outer 100–200 km of the continental crust domain, possibly coeval with SDR emplacement. This is the first identification of three superimposed Rifting settings in the southern South Atlantic realm and is key to understanding the complex Mesozoic breakup history of SW Gondwana.
Giacomo Corti - One of the best experts on this subject based on the ideXlab platform.
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Continental rift evolution: From rift initiation to incipient break-up in the Main Ethiopian Rift, East Africa
Earth-Science Reviews, 2009Co-Authors: Giacomo CortiAbstract:Abstract The Main Ethiopian Rift is a key sector of the East African Rift System that connects the Afar depression, at Red Sea–Gulf of Aden junction, with the Turkana depression and Kenya Rift to the South. It is a magmatic rift that records all the different stages of rift evolution from rift initiation to break-up and incipient oceanic spreading: it is thus an ideal place to analyse the evolution of continental extension, the rupture of lithospheric plates and the dynamics by which distributed continental deformation is progressively focused at oceanic spreading centres. The first tectono-magmatic event related to the Tertiary Rifting was the eruption of voluminous flood basalts that apparently occurred in a rather short time interval at around 30 Ma; strong plateau uplift, which resulted in the development of the Ethiopian and Somalian plateaus now surrounding the rift valley, has been suggested to have initiated contemporaneously or shortly after the extensive flood-basalt volcanism, although its exact timing remains controversial. Voluminous volcanism and uplift started prior to the main Rifting phases, suggesting a mantle plume influence on the Tertiary deformation in East Africa. Different plume hypothesis have been suggested, with recent models indicating the existence of deep superplume originating at the core-mantle boundary beneath southern Africa, rising in a north–northeastward direction toward eastern Africa, and feeding multiple plume stems in the upper mantle. However, the existence of this whole-mantle feature and its possible connection with Tertiary Rifting are highly debated. The main Rifting phases started diachronously along the MER in the Mio-Pliocene; rift propagation was not a smooth process but rather a process with punctuated episodes of extension and relative quiescence. Rift location was most probably controlled by the reactivation of a lithospheric-scale pre-Cambrian weakness; the orientation of this weakness (roughly NE–SW) and the Late Pliocene (post 3.2 Ma)-recent extensional stress field generated by relative motion between Nubia and Somalia plates (roughly ESE–WNW) suggest that oblique Rifting conditions have controlled rift evolution. However, it is still unclear if these kinematical boundary conditions have remained steady since the initial stages of Rifting or the kinematics has changed during the Late Pliocene or at the Pliocene–Pleistocene boundary. Analysis of geological–geophysical data suggests that continental Rifting in the MER evolved in two different phases. An early (Mio-Pliocene) continental Rifting stage was characterised by displacement along large boundary faults, subsidence of rift depression with local development of deep (up to 5 km) asymmetric basins and diffuse magmatic activity. In this initial phase, magmatism encompassed the whole rift, with volcanic activity affecting the rift depression, the major boundary faults and limited portions of the rift shoulders (off-axis volcanism). Progressive extension led to the second (Pleistocene) Rifting stage, characterised by a riftward narrowing of the volcano-tectonic activity. In this phase, the main boundary faults were deactivated and extensional deformation was accommodated by dense swarms of faults (Wonji segments) in the thinned rift depression. The progressive thinning of the continental lithosphere under constant, prolonged oblique Rifting conditions controlled this migration of deformation, possibly in tandem with the weakening related to magmatic processes and/or a change in rift kinematics. Owing to the oblique Rifting conditions, the fault swarms obliquely cut the rift floor and were characterised by a typical right-stepping arrangement. Ascending magmas were focused by the Wonji segments, with eruption of magmas at surface preferentially occurring along the oblique faults. As soon as the volcano-tectonic activity was localised within Wonji segments, a strong feedback between deformation and magmatism developed: the thinned lithosphere was strongly modified by the extensive magma intrusion and extension was facilitated and accommodated by a combination of magmatic intrusion, dyking and faulting. In these conditions, focused melt intrusion allows the rupture of the thick continental lithosphere and the magmatic segments act as incipient slow-spreading mid-ocean spreading centres sandwiched by continental lithosphere. Overall the above-described evolution of the MER (at least in its northernmost sector) documents a transition from fault-dominated rift morphology in the early stages of extension toward magma-assisted Rifting during the final stages of continental break-up. A strong increase in coupling between deformation and magmatism with extension is documented, with magma intrusion and dyking playing a larger role than faulting in strain accommodation as Rifting progresses to seafloor spreading.
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Control of rift obliquity on the evolution and segmentation of the main Ethiopian rift
Nature Geoscience, 2008Co-Authors: Giacomo CortiAbstract:The main Ethiopian rift has evolved in two stages, with successive activation of differently oriented fault systems. Analogue modelling of the Earth’s lithosphere demonstrates that such a rift evolution requires neither magma weakening nor a change in plate kinematics. The main Ethiopian rift is an active rift in the break-up stage, and it marks the incipient boundary between the Nubia and Somalia plates1. Rifting started with the activation of large boundary faults and diffuse volcanism, followed by focused magmatism and faulting in the rift floor, along step-like segments oblique to the rift axis that now act as a protoridge for future seafloor spreading2. This concentration of volcano-tectonic activity has been thought to be either magma assisted2,3 or controlled by a change in rift kinematics, with a late oblique Rifting phase that would have caused the development of the step-like fault segments that focused magma upwelling4,5. Geodetic6,7, seismic8 and stress-field9 data confirm current oblique Rifting kinematics, but plate kinematics models do not predict a change in Nubia–Somalia motion in the past 11 million years10. Here, I use lithospheric-scale analogue models of oblique Rifting to analyse the development of the main Ethiopian rift. I find that neither magma weakening nor a change in plate kinematics are required to simulate a two-phase evolution with successive activation of differently oriented fault systems. I conclude that rift evolution and segmentation are controlled by rift obliquity, independent of magmatic processes.
