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您的检索式：作者名="HOOPES DAVID G"
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| 1 | Guest editor's introduction to the special issue:why is there a resourced-based view? toward a theory of competitive heterogeneity显示文摘 | HOOPES DAVID G MADSEN TAMMY L WALKER GORDON | 2003 | Strategic Management Journal2003，24，： | 1 |
| 2 | Small-Scale Mineralogical Heterogeneity from Variations in Phase Assemblages in the Transition Zone and D' Layer Predicted by Convection Modelling显示文摘Small-scale heterogeneity in the deep mantle is concentrated in the upper-mantle transi-tion zone(TZ),in the depth range 410-660 km and also at the bottom 250 km D' region.This encour-ages a more detailed investigation of the potential for seismic reflectivity imaging by modelling hetero-geneous structures in mantle convection models including phase transitions of the TZ and D' regions.We applied finite elements with variable spacing near the boundary layers in 2-D cylindrical geometry that allow for sufficient spatial resolution.We investigated several models including an extended Bous-sinesq(EBA) model,focused on the D' region,and a compressible(ALA) model for the TZ region.The results for the D' region show typical lens-shaped structures of post-perovskite(PPV) embedded in the perovskite(PV) background mantle,where the thickness of the lenses,at 200-400 km,strongly depends on the Clapeyron slope of the PV-PPV transition.A second phase transition(double crossing) occurs in case the core temperature is higher than the in-tercept temperature Ti.Our phase-dependent rheology results in contrasting effective viscosity between PV and PPV.Our model results reveal a distinctly clear mechanical weakening of the PPV lenses with about an order of magnitude lower viscosity.The shear wave-speed distribu-tions computed from our convection results are strongly correlated with the heterogeneous dis-tribution of the mineral phase.Gradients in the seismic wave-speed that are the target of seis-mological reflectivity imaging are clearly revealed.The wave-speed results show a clear resolution of the top and bottom interfaces of the PPV lenses.Our ALA model for the TZ is based on a thermodynamical model for the magnesium end-member of an olivine-pyroxene mantle.The model predicts a much more complex distribution of min-eral phases,compared to our D' results,in agreement with the greater number of mineral phases in-volved in the olivine-pyroxene phase diagram for the P,T conditions of the transition zone.Near cold downwelling flows representing subducting lithospheric slabs,where the local geotherm can differ by up to 1 000 K from the horizontal average,and small-scale lateral variations in the mineral phases can occur. | Arie P van den Berg David A Yuen Michael H G Jacobs Maarten V de Hoop | 2011 | Journal of Earth Science2011，22，2： | 0 |
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