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Journal of Mining Science

, Volume 46, Issue 5, pp 495–502 | Cite as

High temperature rheology of synthetic two-phase gabbroic aggregates: microstructural heterogeneities and local deformation mechanism

  • J. Raphanel
  • A. Dimanov
  • L. A. Nazarova
  • L. A. Nazarov
  • A. I. Artemova
Geomechanics

Abstract

The high-temperature rheology of heterogeneous anorthite — diopside aggregates has been investigated numerically, in support to experimental data obtained by triaxial torsion tests, performed at high pressure (400 MPa) and temperature (1150° C). The mechanical data exhibited linear viscous flow. Accordingly, scanning electron microscopy revealed grain sliding mechanisms, but also crystal slip plasticity, recrystallization and micro-fracturing. Finite element computations at the aggregate scale aimed at the understanding of the sequence of active mechanisms and their link to the macroscopic behavior. For instance, we show that the presence of coarser and stronger diopside inclusions in weaker and fine grained anorthite matrix results in very heterogeneous local stress fields, allowing for the activation of multiple deformation mechanisms. Our study indicates that shear zones in the lower crust should be dominated by Newtonian rheology in relation with grain sliding mechanisms, even though complementary accommodation mechanisms such as crystal plasticity and damage may be necessary at the local scale, due to the heterogeneous microstructures.

Key Words

Rock laboratory experiment high pressure and temperature equation of state numerical modeling 

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Copyright information

© Pleiades Publishing, Ltd. 2010

Authors and Affiliations

  • J. Raphanel
    • 1
  • A. Dimanov
    • 1
  • L. A. Nazarova
    • 2
  • L. A. Nazarov
    • 2
  • A. I. Artemova
    • 3
  1. 1.Laboratoire de Mécanique des Solides, CNRS UMR 7649Ecole Polytechnique, PalaiseauParisFrance
  2. 2.Institute of Mining, Siberian BranchRussian Academy of SciencesNovosibirskRussia
  3. 3.Novosibirsk State UniversityNovosibirskRussia

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