A5026798985- Geomagnetism and Paleomagnetism Studies
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Planetary Science and Exploration
- Geophysics and Gravity Measurements
- High-pressure geophysics and materials
- Geological and Geochemical Analysis
- Geology and Paleoclimatology Research
- earthquake and tectonic studies
- Stellar, planetary, and galactic studies
- Magnetic and Electromagnetic Effects
- Fluid Dynamics and Turbulent Flows
- Geophysical and Geoelectrical Methods
- Seismic Waves and Analysis
- Isotope Analysis in Ecology
- Space Exploration and Technology
- Methane Hydrates and Related Phenomena
- Seismic Imaging and Inversion Techniques
- Astronomical Observations and Instrumentation
- Reservoir Engineering and Simulation Methods
- Satellite Image Processing and Photogrammetry
- Hydrocarbon exploration and reservoir analysis
- Meteorological Phenomena and Simulations
- Remote Sensing and LiDAR Applications
- Geochemistry and Geologic Mapping
Max Planck Institute for Solar System Research
2015-2024
Milwaukee Public Schools
2020
Max Planck Society
2010-2019
Charles River Laboratories (Netherlands)
2015
Imperial College London
2010
Technical University of Denmark
2010
International Space Science Institute
2010
Scripps Institution of Oceanography
2010
University of California, San Diego
2010
Centre National de la Recherche Scientifique
2010
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not.The documents may come from teaching institutions in France abroad, public private centers.L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de scientifiques niveau recherche, publiés ou non, émanant des établissements d'enseignement recherche français étrangers, laboratoires publics privés. Scaling properties...
We report a systematic study on the conditions under which an endothermic phase transition can enforce layered convection. Two‐dimensional numerical calculations of convection in domain containing divariant change were performed framework “extended Boussinesq approximation,” i.e., considering effects adiabatic gradient, latent heat, and frictional heating energy equation. find that critical value negative Clapeyron slope, must be surpassed order to induce convection, decreases magnitude with...
Subducted oceanic crust, transformed into dense mineral assemblages at high pressure, may gravitationally segregate the bottom of convecting mantle, for example, D ″ layer. Here it could be stored a long enough time to develop an “enriched” isotopic signature, before is recycled in mantle plumes and hence control geochemical character hot‐spot basalts. We study both geodynamical aspects this hypothesis two‐dimensional numerical convection models, which plate motion imposed by velocity...
The Dawn spacecraft targeted 4 Vesta, believed to be a remnant intact protoplanet from the earliest epoch of solar system formation, based on analyses howardite-eucrite-diogenite (HED) meteorites that indicate differentiated parent body. observations reveal giant basin at Vesta's south pole, whose excavation was sufficient produce Vesta-family asteroids (Vestoids) and HED meteorites. spatially resolved mineralogy surface reflects composition meteorites, confirming formation crust by melting...
The influence of non-linear stress-strain rate relation on thermal convection in a fluid whose rheological properties are also pressure- and temperature-dependent is studied series numerical models. A finite element method with an upwind weighted residual technique B splines applied to obtain steady state time-dependent solutions two-dimensional rectangular enclosures. cubic power law rheology taken most cases the result compared Newtonian convection. model calculations comprise different...
A two-dimensional numerical convection model in cartesian geometry is used to study the influence of trench migration on ability subducted slabs penetrate an endothermic phase boundary at 660 km depth. The transient subduction history oceanic plate modelled by imposing and motion surface. viscosity depends temperature variety styles slab behaviour found, depending predominantly velocity. When retreat faster than 2–4 cm/a, descending flattens above boundary. At slower rates it penetrates...
Continental flood basalts (CFB) are commonly said to form by direct melting of metasomatized lithospheric mantle, either during major extension or when a mantle plume impinges on the base lithosphere. We tested these ideas in thermomechanical model that combines dynamics and convection. Dry was assumed, proportions melt from different source regions were monitored. In all cases, >96% found come asthenosphere plume, with minimal amounts continental During passive lithosphere total amount...
We present seismic images of the upper mantle below Quaternary Eifel volcanic fields, Germany, determined by teleseismic travel time tomography. The data were measured at a dedicated network more than 200 stations. Our results show columnar low P-velocity anomaly in with lateral contrast up to 2%. 100 km wide structure extends least 400 depth and is equivalent about 150–200 K excess temperature. This clear evidence for plume region comparatively minor volcanism suggests that deep plumes...
Numerical calculations of fluid dynamos powered by thermal convection in a rotating, electrically conducting spherical shell are analyzed. We find two regimes nonreversing, strong field at Ekman number 10 −4 and Rayleigh numbers up to 11 times critical. In the strongly columnar regime, occurs only exterior inner core tangent cylinder, form narrow vortices elongated parallel spin axis. Columnar contains large amounts negative helicity northern hemisphere positive southern results dynamo...
We have carried out a comparison study for set of benchmark problems which are relevant convection in the Earth's mantle. The cases comprise steady isoviscous convection, variable viscosity and time-dependent with internal heating. compare Nusselt numbers, velocity, temperature, heat-flow, topography geoid data. Among applied codes finite-difference, finite-element spectral methods. In synthesis we give best estimates 'true' solutions ranges uncertainty. recommend these data validation future.
We study the dynamics of melting in Hawaiian plume using a 3D variable-viscosity convection model outfitted with parameterization that permits calculation local rate and distribution buoyant depleted residual material. From suite 45 steady-state numerical experiments, we derive complete scaling laws for total M height H width W topographic swell as functions lithospheric thickness zl plume's maximum potential temperature θi, thermal buoyancy flux B, minimum viscosity ηp. Assuming...
We analyse ∼ 50 3-D numerical calculations of hydrodynamic dynamos driven by convection in a spherical shell. examine rigid and stress-free boundaries, with Prandtl number 1, magnetic numbers the range 0.5–5, Ekman E=10− 3–10− 4 Rayleigh to 15 times critical. No parametrizations such as hyperviscosities are used. Successful compared non-magnetic solutions. Results for various spectral truncations suggest that well resolved when kinetic energy drops more than two orders magnitude from peak...
We have compared several methods of studying thermochemical convection in a Boussinesq fluid at infinite Prandtl number. For the representation chemical heterogeneity tracer, marker chain, and field are employed. In case an isothermal Rayleigh‐Taylor instability, good agreement is found for initial rise unstable lower layer; however, timing location later smaller‐scale instabilities may differ between methods. simulation entrainment by thermal dense layer bottom mantle we few overturn times....
In order to understand better the dynamics of hot spots such as Hawaii, we present a three‐dimensional numerical model for interaction thermal plume with moving lithosphere. The domain is rectangular box filled fluid whose viscosity depends upon temperature and pressure. lithosphere represented by layer cold, highly viscous an imposed horizontal velocity U in x direction, generated circular anomaly on bottom box. steady flow determined numerically using hybrid spectral/finite difference...
Thermal evolution models for the earth which are based on a parameterization of convective heat transport critically reexamined. Traditionally, it has been assumed that temperature dependence mantle viscosity implies internal and loss strongly coupled. Recent numerical work by variable convection demonstrates flow may in fact be much weaker than expected. I compare thermal with strong weak temperature. With dependence, plate velocities Archean were not more 50% higher today, while larger...