The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform

Bernard Pontoise - One of the best experts on this subject based on the ideXlab platform.

  • Multibeam bathymetry and sidescan imaging of the Rivera Transform–Moctezuma Spreading Segment junction, northern East Pacific Rise: New constraints on Rivera–Pacific relative Plate Motion
    Tectonophysics, 2008
    Co-Authors: W. Bandy, François Michaud, Jérôme Dyment, Carlos Mortera-gutierrez, Jacques Bourgois, Thierry Calmus, Marc Sosson, J. Ortega-ramirez, Jean-yves Royer, Bernard Pontoise
    Abstract:

    To better understand the recent Motion of the Pacific Plate relative to the Rivera Plate and to better define the limitations of the existing Rivera–Pacific Plate Motion models for accurately predicting this Motion, total-field magnetic data, multibeam bathymetric data and sidescan sonar images were collected during the BART and FAMEX campaigns of the N/O L'Atalante conducted in April and May 2002 in the area surrounding the Moctezuma Spreading Segment of the East Pacific Rise, located offshore of Manzanillo, Mexico, at 106°16′W, between 17.8°N and 18.5°N. Among the main results are: (1) the principle transform displacement zone of the Rivera Transform is narrow and well defined east of 107o15′W and these azimuths should be used preferentially when deriving new Plate Motion models, and (2) spreading rates along the Moctezuma Spreading Segment should not be used in Plate Motion studies as either seafloor spreading has been accommodated at more than one location since the initiation of seafloor spreading in the area of the Moctezuma Spreading Segment, or this spreading center is not a Rivera–Pacific Plate boundary as has been previously assumed. Comparison of observed transform azimuths with those predicted by the best-fit poles of six previous models of Rivera–Pacific relative Motion indicate that, in the study area, a significant systematic bias is present in the predictions of Rivera–Pacific Motion. Although the exact source of this bias remains unclear, this bias indicates the need to derive a new Rivera–Pacific relative Plate Motion model.

  • Multibeam bathymetry and sidescan imaging of the Rivera Transform–Moctezuma Spreading Segment junction, northern East Pacific Rise: New constraints on Rivera–Pacific relative Plate Motion
    Tectonophysics, 2008
    Co-Authors: William L. Bandy, François Michaud, Jérôme Dyment, Carlos Mortera-gutierrez, Jacques Bourgois, Thierry Calmus, Marc Sosson, J. Ortega-ramirez, Jean-yves Royer, Bernard Pontoise
    Abstract:

    International audienceTo better understand the recent Motion of the Pacific Plate relative to the Rivera Plate and to better define the limitations of the existing Rivera–Pacific Plate Motion models for accurately predicting this Motion, total-field magnetic data, multibeam bathymetric data and sidescan sonar images were collected during the BART and FAMEX campaigns of the N/O L'Atalante conducted in April and May 2002 in the area surrounding the Moctezuma Spreading Segment of the East Pacific Rise, located offshore of Manzanillo, Mexico, at 106°16′W, between 17.8°N and 18.5°N. Among the main results are: (1) the principle transform displacement zone of the Rivera Transform is narrow and well defined east of 107o15′W and these azimuths should be used preferentially when deriving new Plate Motion models, and (2) spreading rates along the Moctezuma Spreading Segment should not be used in Plate Motion studies as either seafloor spreading has been accommodated at more than one location since the initiation of seafloor spreading in the area of the Moctezuma Spreading Segment, or this spreading center is not a Rivera–Pacific Plate boundary as has been previously assumed. Comparison of observed transform azimuths with those predicted by the best-fit poles of six previous models of Rivera–Pacific relative Motion indicate that, in the study area, a significant systematic bias is present in the predictions of Rivera–Pacific Motion. Although the exact source of this bias remains unclear, this bias indicates the need to derive a new Rivera–Pacific relative Plate Motion model

Hanspeter Bunge - One of the best experts on this subject based on the ideXlab platform.

  • rapid Plate Motion variations through geological time observations serving geodynamic interpretation
    Annual Review of Earth and Planetary Sciences, 2015
    Co-Authors: Giampiero Iaffaldano, Hanspeter Bunge
    Abstract:

    Past and current Plate Motions are increasingly well mapped from high-temporal-resolution paleomagnetic and geodetic studies, revealing rapid variations that occur on short timescales relative to the time it takes for the large-scale structure associated with mantle buoyancy to evolve. The rates of change of Plate velocities hold key information on the geodynamic, tectonic, and Earth's surface processes that may have caused them. Rapid Plate Motion changes thus provide us with a unique opportunity to quantify the forcing associated with these processes. Important mechanisms capable of inducing such rapid changes include evolving Plate boundary forces, for example, those associated with slab sinking or orogeny along convergent margins, as well as temporal variations in pressure-driven flow within the asthenosphere that link Plate velocity variations explicitly to changes in dynamic topography. Here, we focus on (a) findings from recent kinematic observations and (b) the quantitative framework that allows t...

  • Monsoon speeds up Indian Plate Motion
    Earth and Planetary Science Letters, 2011
    Co-Authors: Giampiero Iaffaldano, Laurent Husson, Hanspeter Bunge
    Abstract:

    article i nfo Short-term Plate Motion variations on the order of a few Myr are a powerful probe into the nature of Plate boundary forces, as mantle-related buoyancies evolve on longer time-scales. New reconstructions of the ocean-floor spreading record reveal an increasing number of such variations, but the dynamic mechanisms producing them are still unclear. Here we show quantitatively that climate changes may impact the short- term evolution of Plate Motion by linking explicitly the observed counter-clockwise rotation of the Indian Plate since ~10 Ma to increased erosion and reduced elevation along the eastern Himalayas, due to temporal variations in monsoon intensity. By assimilating observations into empirical relations for the competing contributions of erosion and mountain building, we estimate the first-order decrease in elevation along the eastern Himalayas since initial strengthening of the monsoon. Furthermore, we show with global geodynamic models of the coupled mantle/lithosphere system that the inferred reduction in elevation is consistent with the Indian Plate Motion record over the same period of time, and that lowered gravitational potential energy in the eastern Himalayas following stronger erosion is a key factor to foster Plate convergence in this region. Our study implicates lateral variations in Plate coupling and their temporal changes as an efficient source to induce an uncommon form of Plate Motion where the Euler pole falls within its associated Plate.

  • Monsoon speeds up Indian Plate Motion
    Earth and Planetary Science Letters, 2011
    Co-Authors: Giampiero Iaffaldano, Laurent Husson, Hanspeter Bunge
    Abstract:

    International audienceShort-term Plate Motion variations on the order of a few Myr are a powerful probe into the nature of Plate boundary forces, as mantle-related buoyancies evolve on longer time-scales. New reconstructions of the ocean-floor spreading record reveal an increasing number of such variations, but the dynamic mechanisms producing them are still unclear. Here we show quantitatively that climate changes may impact the shortterm evolution of Plate Motion by linking explicitly the observed counter-clockwise rotation of the Indian Plate since ~10 Ma to increased erosion and reduced elevation along the eastern Himalayas, due to temporal variations in monsoon intensity. By assimilating observations into empirical relations for the competing contributions of erosion and mountain building, we estimate the first-order decrease in elevation along the eastern Himalayas since initial strengthening of the monsoon. Furthermore, we show with global geodynamic models of the coupled mantle/lithosphere system that the inferred reduction in elevation is consistent with the Indian Plate Motion record over the same period of time, and that lowered gravitational potential energy in the eastern Himalayas following stronger erosion is a key factor to foster Plate convergence in this region. Our study implicates lateral variations in Plate coupling and their temporal changes as an efficient source to induce an uncommon form of Plate Motion where the Euler pole falls within its associated Plate

  • Monsoon speeds up Indian Plate Motion
    Earth and Planetary Science Letters, 2011
    Co-Authors: Gampiero Iaffaldano, Laurent Husson, Hanspeter Bunge
    Abstract:

    Short-term Plate Motion variations on the order of a few Myr are a powerful probe into the nature of Plate boundary forces, as mantle-related buoyancies evolve on longer time-scales. New reconstructions of the ocean-floor spreading record reveal an increasing number of such variations, but the dynamic mechanisms producing them are still unclear. Here we show quantitatively that climate changes may impact the shortterm evolution of Plate Motion by linking explicitly the observed counter-clockwise rotation of the Indian Plate since ~10 Ma to increased erosion and reduced elevation along the eastern Himalayas, due to temporal variations in monsoon intensity. By assimilating observations into empirical relations for the competing contributions of erosion and mountain building, we estimate the first-order decrease in elevation along the eastern Himalayas since initial strengthening of the monsoon. Furthermore, we show with global geodynamic models of the coupled mantle/lithosphere system that the inferred reduction in elevation is consistent with the Indian Plate Motion record over the same period of time, and that lowered gravitational potential energy in the eastern Himalayas following stronger erosion is a key factor to foster Plate convergence in this region. Our study implicates lateral variations in Plate coupling and their temporal changes as an efficient source to induce an uncommon form of Plate Motion where the Euler pole falls within its associated Plate.

  • Mantle-circulation models with sequential data assimilation: inferring present-day mantle structure from Plate-Motion histories.
    Philosophical transactions. Series A Mathematical physical and engineering sciences, 2002
    Co-Authors: Hanspeter Bunge, Mark A. Richards, John R. Baumgardner
    Abstract:

    Data assimilation is an approach to studying geodynamic models consistent simultaneously with observables and the governing equations of mantle flow. Such an approach is essential in mantle circulation models, where we seek to constrain an unknown initial condition some time in the past, and thus cannot hope to use first-principles convection calculations to infer the flow history of the mantle. One of the most important observables for mantle-flow history comes from models of Mesozoic and Cenozoic Plate Motion that provide constraints not only on the surface velocity of the mantle but also on the evolution of internal mantle-buoyancy forces due to subducted oceanic slabs. Here we present five mantle circulation models with an assimilated Plate-Motion history spanning the past 120 Myr, a time period for which reliable Plate-Motion reconstructions are available. All models agree well with upper- and mid-mantle heterogeneity imaged by seismic tomography. A simple standard model of whole-mantle convection, including a factor 40 viscosity increase from the upper to the lower mantle and predominantly internal heat generation, reveals downwellings related to Farallon and Tethys subduction. Adding 35% bottom heating from the core has the predictable effect of producing prominent high-temperature anomalies and a strong thermal boundary layer at the base of the mantle. Significantly delaying mantle flow through the transition zone either by modelling the dynamic effects of an endothermic phase reaction or by including a steep, factor 100, viscosity rise from the upper to the lower mantle results in substantial transition-zone heterogeneity, enhanced by the effects of trench migration implicit in the assimilated Plate-Motion history. An expected result is the failure to account for heterogeneity structure in the deepest mantle below 1500 km, which is influenced by Jurassic Plate Motions and thus cannot be modelled from sequential assimilation of Plate Motion histories limited in age to the Cretaceous. This result implies that sequential assimilation of past Plate-Motion models is ineffective in studying the temporal evolution of core-mantle-boundary heterogeneity, and that a method for extrapolating present-day information backwards in time is required. For short time periods (of the order of perhaps a few tens of Myr) such a method exists in the form of crude 'backward' convection calculations. For longer time periods (of the order of a mantle overturn), a rigorous approach to extrapolating information back in time exists in the form of iterative nonlinear optimization methods that carry assimilated information into the past through the use of an adjoint mantle convection model.

Jacques Bourgois - One of the best experts on this subject based on the ideXlab platform.

  • Multibeam bathymetry and sidescan imaging of the Rivera Transform–Moctezuma Spreading Segment junction, northern East Pacific Rise: New constraints on Rivera–Pacific relative Plate Motion
    Tectonophysics, 2008
    Co-Authors: W. Bandy, François Michaud, Jérôme Dyment, Carlos Mortera-gutierrez, Jacques Bourgois, Thierry Calmus, Marc Sosson, J. Ortega-ramirez, Jean-yves Royer, Bernard Pontoise
    Abstract:

    To better understand the recent Motion of the Pacific Plate relative to the Rivera Plate and to better define the limitations of the existing Rivera–Pacific Plate Motion models for accurately predicting this Motion, total-field magnetic data, multibeam bathymetric data and sidescan sonar images were collected during the BART and FAMEX campaigns of the N/O L'Atalante conducted in April and May 2002 in the area surrounding the Moctezuma Spreading Segment of the East Pacific Rise, located offshore of Manzanillo, Mexico, at 106°16′W, between 17.8°N and 18.5°N. Among the main results are: (1) the principle transform displacement zone of the Rivera Transform is narrow and well defined east of 107o15′W and these azimuths should be used preferentially when deriving new Plate Motion models, and (2) spreading rates along the Moctezuma Spreading Segment should not be used in Plate Motion studies as either seafloor spreading has been accommodated at more than one location since the initiation of seafloor spreading in the area of the Moctezuma Spreading Segment, or this spreading center is not a Rivera–Pacific Plate boundary as has been previously assumed. Comparison of observed transform azimuths with those predicted by the best-fit poles of six previous models of Rivera–Pacific relative Motion indicate that, in the study area, a significant systematic bias is present in the predictions of Rivera–Pacific Motion. Although the exact source of this bias remains unclear, this bias indicates the need to derive a new Rivera–Pacific relative Plate Motion model.

  • Multibeam bathymetry and sidescan imaging of the Rivera Transform–Moctezuma Spreading Segment junction, northern East Pacific Rise: New constraints on Rivera–Pacific relative Plate Motion
    Tectonophysics, 2008
    Co-Authors: William L. Bandy, François Michaud, Jérôme Dyment, Carlos Mortera-gutierrez, Jacques Bourgois, Thierry Calmus, Marc Sosson, J. Ortega-ramirez, Jean-yves Royer, Bernard Pontoise
    Abstract:

    International audienceTo better understand the recent Motion of the Pacific Plate relative to the Rivera Plate and to better define the limitations of the existing Rivera–Pacific Plate Motion models for accurately predicting this Motion, total-field magnetic data, multibeam bathymetric data and sidescan sonar images were collected during the BART and FAMEX campaigns of the N/O L'Atalante conducted in April and May 2002 in the area surrounding the Moctezuma Spreading Segment of the East Pacific Rise, located offshore of Manzanillo, Mexico, at 106°16′W, between 17.8°N and 18.5°N. Among the main results are: (1) the principle transform displacement zone of the Rivera Transform is narrow and well defined east of 107o15′W and these azimuths should be used preferentially when deriving new Plate Motion models, and (2) spreading rates along the Moctezuma Spreading Segment should not be used in Plate Motion studies as either seafloor spreading has been accommodated at more than one location since the initiation of seafloor spreading in the area of the Moctezuma Spreading Segment, or this spreading center is not a Rivera–Pacific Plate boundary as has been previously assumed. Comparison of observed transform azimuths with those predicted by the best-fit poles of six previous models of Rivera–Pacific relative Motion indicate that, in the study area, a significant systematic bias is present in the predictions of Rivera–Pacific Motion. Although the exact source of this bias remains unclear, this bias indicates the need to derive a new Rivera–Pacific relative Plate Motion model

J. Ortega-ramirez - One of the best experts on this subject based on the ideXlab platform.

  • Multibeam bathymetry and sidescan imaging of the Rivera Transform–Moctezuma Spreading Segment junction, northern East Pacific Rise: New constraints on Rivera–Pacific relative Plate Motion
    Tectonophysics, 2008
    Co-Authors: W. Bandy, François Michaud, Jérôme Dyment, Carlos Mortera-gutierrez, Jacques Bourgois, Thierry Calmus, Marc Sosson, J. Ortega-ramirez, Jean-yves Royer, Bernard Pontoise
    Abstract:

    To better understand the recent Motion of the Pacific Plate relative to the Rivera Plate and to better define the limitations of the existing Rivera–Pacific Plate Motion models for accurately predicting this Motion, total-field magnetic data, multibeam bathymetric data and sidescan sonar images were collected during the BART and FAMEX campaigns of the N/O L'Atalante conducted in April and May 2002 in the area surrounding the Moctezuma Spreading Segment of the East Pacific Rise, located offshore of Manzanillo, Mexico, at 106°16′W, between 17.8°N and 18.5°N. Among the main results are: (1) the principle transform displacement zone of the Rivera Transform is narrow and well defined east of 107o15′W and these azimuths should be used preferentially when deriving new Plate Motion models, and (2) spreading rates along the Moctezuma Spreading Segment should not be used in Plate Motion studies as either seafloor spreading has been accommodated at more than one location since the initiation of seafloor spreading in the area of the Moctezuma Spreading Segment, or this spreading center is not a Rivera–Pacific Plate boundary as has been previously assumed. Comparison of observed transform azimuths with those predicted by the best-fit poles of six previous models of Rivera–Pacific relative Motion indicate that, in the study area, a significant systematic bias is present in the predictions of Rivera–Pacific Motion. Although the exact source of this bias remains unclear, this bias indicates the need to derive a new Rivera–Pacific relative Plate Motion model.

  • Multibeam bathymetry and sidescan imaging of the Rivera Transform–Moctezuma Spreading Segment junction, northern East Pacific Rise: New constraints on Rivera–Pacific relative Plate Motion
    Tectonophysics, 2008
    Co-Authors: William L. Bandy, François Michaud, Jérôme Dyment, Carlos Mortera-gutierrez, Jacques Bourgois, Thierry Calmus, Marc Sosson, J. Ortega-ramirez, Jean-yves Royer, Bernard Pontoise
    Abstract:

    International audienceTo better understand the recent Motion of the Pacific Plate relative to the Rivera Plate and to better define the limitations of the existing Rivera–Pacific Plate Motion models for accurately predicting this Motion, total-field magnetic data, multibeam bathymetric data and sidescan sonar images were collected during the BART and FAMEX campaigns of the N/O L'Atalante conducted in April and May 2002 in the area surrounding the Moctezuma Spreading Segment of the East Pacific Rise, located offshore of Manzanillo, Mexico, at 106°16′W, between 17.8°N and 18.5°N. Among the main results are: (1) the principle transform displacement zone of the Rivera Transform is narrow and well defined east of 107o15′W and these azimuths should be used preferentially when deriving new Plate Motion models, and (2) spreading rates along the Moctezuma Spreading Segment should not be used in Plate Motion studies as either seafloor spreading has been accommodated at more than one location since the initiation of seafloor spreading in the area of the Moctezuma Spreading Segment, or this spreading center is not a Rivera–Pacific Plate boundary as has been previously assumed. Comparison of observed transform azimuths with those predicted by the best-fit poles of six previous models of Rivera–Pacific relative Motion indicate that, in the study area, a significant systematic bias is present in the predictions of Rivera–Pacific Motion. Although the exact source of this bias remains unclear, this bias indicates the need to derive a new Rivera–Pacific relative Plate Motion model

Jérôme Dyment - One of the best experts on this subject based on the ideXlab platform.

  • Multibeam bathymetry and sidescan imaging of the Rivera Transform–Moctezuma Spreading Segment junction, northern East Pacific Rise: New constraints on Rivera–Pacific relative Plate Motion
    Tectonophysics, 2008
    Co-Authors: W. Bandy, François Michaud, Jérôme Dyment, Carlos Mortera-gutierrez, Jacques Bourgois, Thierry Calmus, Marc Sosson, J. Ortega-ramirez, Jean-yves Royer, Bernard Pontoise
    Abstract:

    To better understand the recent Motion of the Pacific Plate relative to the Rivera Plate and to better define the limitations of the existing Rivera–Pacific Plate Motion models for accurately predicting this Motion, total-field magnetic data, multibeam bathymetric data and sidescan sonar images were collected during the BART and FAMEX campaigns of the N/O L'Atalante conducted in April and May 2002 in the area surrounding the Moctezuma Spreading Segment of the East Pacific Rise, located offshore of Manzanillo, Mexico, at 106°16′W, between 17.8°N and 18.5°N. Among the main results are: (1) the principle transform displacement zone of the Rivera Transform is narrow and well defined east of 107o15′W and these azimuths should be used preferentially when deriving new Plate Motion models, and (2) spreading rates along the Moctezuma Spreading Segment should not be used in Plate Motion studies as either seafloor spreading has been accommodated at more than one location since the initiation of seafloor spreading in the area of the Moctezuma Spreading Segment, or this spreading center is not a Rivera–Pacific Plate boundary as has been previously assumed. Comparison of observed transform azimuths with those predicted by the best-fit poles of six previous models of Rivera–Pacific relative Motion indicate that, in the study area, a significant systematic bias is present in the predictions of Rivera–Pacific Motion. Although the exact source of this bias remains unclear, this bias indicates the need to derive a new Rivera–Pacific relative Plate Motion model.

  • Multibeam bathymetry and sidescan imaging of the Rivera Transform–Moctezuma Spreading Segment junction, northern East Pacific Rise: New constraints on Rivera–Pacific relative Plate Motion
    Tectonophysics, 2008
    Co-Authors: William L. Bandy, François Michaud, Jérôme Dyment, Carlos Mortera-gutierrez, Jacques Bourgois, Thierry Calmus, Marc Sosson, J. Ortega-ramirez, Jean-yves Royer, Bernard Pontoise
    Abstract:

    International audienceTo better understand the recent Motion of the Pacific Plate relative to the Rivera Plate and to better define the limitations of the existing Rivera–Pacific Plate Motion models for accurately predicting this Motion, total-field magnetic data, multibeam bathymetric data and sidescan sonar images were collected during the BART and FAMEX campaigns of the N/O L'Atalante conducted in April and May 2002 in the area surrounding the Moctezuma Spreading Segment of the East Pacific Rise, located offshore of Manzanillo, Mexico, at 106°16′W, between 17.8°N and 18.5°N. Among the main results are: (1) the principle transform displacement zone of the Rivera Transform is narrow and well defined east of 107o15′W and these azimuths should be used preferentially when deriving new Plate Motion models, and (2) spreading rates along the Moctezuma Spreading Segment should not be used in Plate Motion studies as either seafloor spreading has been accommodated at more than one location since the initiation of seafloor spreading in the area of the Moctezuma Spreading Segment, or this spreading center is not a Rivera–Pacific Plate boundary as has been previously assumed. Comparison of observed transform azimuths with those predicted by the best-fit poles of six previous models of Rivera–Pacific relative Motion indicate that, in the study area, a significant systematic bias is present in the predictions of Rivera–Pacific Motion. Although the exact source of this bias remains unclear, this bias indicates the need to derive a new Rivera–Pacific relative Plate Motion model