The Experts below are selected from a list of 37428 Experts worldwide ranked by ideXlab platform
Alessandro M Forte - One of the best experts on this subject based on the ideXlab platform.
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changes in african topography driven by mantle convection
Nature Geoscience, 2011Co-Authors: Robert Moucha, Alessandro M ForteAbstract:Africa’s topography is characterized by large-scale uplifted domes and subsided basins. Numerical simulations of mantle flow suggest that high topography along Africa’s eastern margin formed as a result of the northward migration of the Tectonic Plate over the African superplume during the past 30 million years.
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recent Tectonic Plate decelerations driven by mantle convection
Geophysical Research Letters, 2009Co-Authors: Alessandro M Forte, Robert Moucha, David B Rowley, S Quere, Jerry X Mitrovica, N A Simmons, Stephen P GrandAbstract:[1] We explore recent changes in Tectonic Plate velocities using a model of mantle flow that is based on a new high-resolution global tomography model derived from simultaneous inversions of global seismic, geodynamic and mineral physical data sets. This Plate-coupled mantle convection model incorporates a viscosity structure that reconciles both glacial isostatic adjustment and global convection-related data sets. The convection model successfully reproduces present-day Plate velocities and global surface gravity and topography constraints. We predict time-dependent changes in mantle buoyancy that give rise to present-day decelerations of several major Plates, in particular the fast-moving Pacific and Nazca Plates. We verify the plausibility of these predicted Plate decelerations using space geodetic and oceanic magnetic anomaly constraints on Tectonic Plate motions. These Plate kinematic constraints are employed to determine a new global map of present-day Plate decelerations that agree well with the mantle flow predictions.
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a new inference of mantle viscosity based upon joint inversion of convection and glacial isostatic adjustment data
Earth and Planetary Science Letters, 2004Co-Authors: Jerry X Mitrovica, Alessandro M ForteAbstract:We present new profiles of mantle viscosity derived on the basis of non-linear, Occam-style joint inversions of an extensive set of data associated with mantle convection and glacial isostatic adjustment (GIA). The convection related observables include satellite-derived free-air gravity harmonics, the geodetically inferred excess ellipticity of the CMB and Tectonic Plate motions. The GIA constraints involve two classes of observables previously shown to be relatively insensitive to errors in the late Pleistocene ice history: the so-called Fennoscandian relaxation spectrum (FRS) and a set of site-specific decay times determined from the postglacial sea-level history in Hudson Bay and Sweden. The inverted viscosity profiles show a significant, three orders of magnitude, increase from the upper mantle (mean value of f4 � 10 20 Pa s) to a high-viscosity (>10 23 Pa s) peak at
Manuele Faccenda - One of the best experts on this subject based on the ideXlab platform.
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intraPlate volcanism originating from upwelling hydrous mantle transition zone
Nature, 2020Co-Authors: Jianfeng Yang, Manuele FaccendaAbstract:Most magmatism occurring on Earth is conventionally attributed to passive mantle upwelling at mid-ocean ridges, to slab devolatilization at subduction zones, or to mantle plumes. However, the widespread Cenozoic intraPlate volcanism in northeast China1–3 and the young petit-spot volcanoes4–7 offshore of the Japan Trench cannot readily be associated with any of these mechanisms. In addition, the mantle beneath these types of volcanism is characterized by zones of anomalously low seismic velocity above and below the transition zone8–12 (a mantle level located at depths between 410 and 660 kilometres). A comprehensive interpretation of these phenomena is lacking. Here we show that most (or possibly all) of the intraPlate and petit-spot volcanism and low-velocity zones around the Japanese subduction zone can be explained by the Cenozoic interaction of the subducting Pacific slab with a hydrous mantle transition zone. Numerical modelling indicates that 0.2 to 0.3 weight per cent of water dissolved in mantle minerals that are driven out from the transition zone in response to subduction and retreat of a Tectonic Plate is sufficient to reproduce the observations. This suggests that a critical amount of water may have accumulated in the transition zone around this subduction zone, as well as in others of the Tethyan Tectonic belt13 that are characterized by intraPlate or petit-spot volcanism and low-velocity zones in the underlying mantle. The widespread intraPlate volcanism in northeast China and the unusual ‘petit-spot’ volcanoes offshore Japan could have resulted from the interaction of the subducting Pacific slab with a hydrous mantle transition zone.
Robert Moucha - One of the best experts on this subject based on the ideXlab platform.
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changes in african topography driven by mantle convection
Nature Geoscience, 2011Co-Authors: Robert Moucha, Alessandro M ForteAbstract:Africa’s topography is characterized by large-scale uplifted domes and subsided basins. Numerical simulations of mantle flow suggest that high topography along Africa’s eastern margin formed as a result of the northward migration of the Tectonic Plate over the African superplume during the past 30 million years.
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recent Tectonic Plate decelerations driven by mantle convection
Geophysical Research Letters, 2009Co-Authors: Alessandro M Forte, Robert Moucha, David B Rowley, S Quere, Jerry X Mitrovica, N A Simmons, Stephen P GrandAbstract:[1] We explore recent changes in Tectonic Plate velocities using a model of mantle flow that is based on a new high-resolution global tomography model derived from simultaneous inversions of global seismic, geodynamic and mineral physical data sets. This Plate-coupled mantle convection model incorporates a viscosity structure that reconciles both glacial isostatic adjustment and global convection-related data sets. The convection model successfully reproduces present-day Plate velocities and global surface gravity and topography constraints. We predict time-dependent changes in mantle buoyancy that give rise to present-day decelerations of several major Plates, in particular the fast-moving Pacific and Nazca Plates. We verify the plausibility of these predicted Plate decelerations using space geodetic and oceanic magnetic anomaly constraints on Tectonic Plate motions. These Plate kinematic constraints are employed to determine a new global map of present-day Plate decelerations that agree well with the mantle flow predictions.
Stephen P Grand - One of the best experts on this subject based on the ideXlab platform.
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evidence for long lived subduction of an ancient Tectonic Plate beneath the southern indian ocean
Geophysical Research Letters, 2015Co-Authors: N A Simmons, S C Myers, G Johannesson, Eric Matzel, Stephen P GrandAbstract:In this study, ancient subducted Tectonic Plates have been observed in past seismic images of the mantle beneath North America and Eurasia, and it is likely that other ancient slab structures have remained largely hidden, particularly in the seismic-data-limited regions beneath the vast oceans in the Southern Hemisphere. Here we present a new global tomographic image, which shows a slab-like structure beneath the southern Indian Ocean with coherency from the upper mantle to the core-mantle boundary region—a feature that has never been identified. We postulate that the structure is an ancient Tectonic Plate that sank into the mantle along an extensive intraoceanic subduction zone that migrated southwestward across the ancient Tethys Ocean in the Mesozoic Era. Slab material still trapped in the transition zone is positioned near the edge of East Gondwana at 140 Ma suggesting that subduction terminated near the margin of the ancient continent prior to breakup and subsequent dispersal of its subcontinents.
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recent Tectonic Plate decelerations driven by mantle convection
Geophysical Research Letters, 2009Co-Authors: Alessandro M Forte, Robert Moucha, David B Rowley, S Quere, Jerry X Mitrovica, N A Simmons, Stephen P GrandAbstract:[1] We explore recent changes in Tectonic Plate velocities using a model of mantle flow that is based on a new high-resolution global tomography model derived from simultaneous inversions of global seismic, geodynamic and mineral physical data sets. This Plate-coupled mantle convection model incorporates a viscosity structure that reconciles both glacial isostatic adjustment and global convection-related data sets. The convection model successfully reproduces present-day Plate velocities and global surface gravity and topography constraints. We predict time-dependent changes in mantle buoyancy that give rise to present-day decelerations of several major Plates, in particular the fast-moving Pacific and Nazca Plates. We verify the plausibility of these predicted Plate decelerations using space geodetic and oceanic magnetic anomaly constraints on Tectonic Plate motions. These Plate kinematic constraints are employed to determine a new global map of present-day Plate decelerations that agree well with the mantle flow predictions.
Grieve, Stuart W.d. - One of the best experts on this subject based on the ideXlab platform.
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Differences in channel and hillslope geometry record a migrating uplift wave at the Mendocino Triple Junction
Geological Society of America, 2020Co-Authors: Clubb, Fiona J., Mudd, Simon M., Hurst, Martin D., Grieve, Stuart W.d.Abstract:Tectonic Plate motion, and the resulting change in land surface elevation, has been shown to have a fundamental impact on landscape morphology. Changes to uplift rates can drive a response in fluvial channels, which then drives changes to hillslopes. As hillslopes respond on different timescales than fluvial channels, investigating the geometry of channels and hillslopes in concert provides novel opportunities to examine how uplift rates may have changed through time. Here we perform coupled topographic analysis of channel and hillslope geometry across a series of catchments at the Mendocino Triple Junction (MTJ) in Northern California. These catchments are characterized by an order of magnitude difference in uplift rate from north to south. We find that dimensionless hillslope relief closely matches the uplift signal across the area and is positively correlated with channel steepness. Furthermore, the range of uncertainty in hillslope relief is lower than that of channel steepness, suggesting that it may be a more reliable recorder of uplift in the MTJ region. We find that hilltop curvature lags behind relief in its response to uplift, which in turn lags 23 behind channel response. These combined metrics show the northwards migration of the MTJ and the corresponding uplift field from topographic data alone
