HR: 0800h
AN: T21B-0465    [Abstracts]
TI: Pressure Solution: a Voigt-type Visco-Plastic Model with a Cole-Cole Distribution of Relaxation Times
AU: Leroy, P
EM: leroy@cerege.fr
AF: CNRS-CEREGE, Europole de l'Arbois, 13545 Aix-en-Provence, cedex 4, Aix-en-Provence, 13545 France
AU: * Revil, A
EM: revil@cerege.fr
AF: CNRS-CEREGE, Europole de l'Arbois, 13545 Aix-en-Provence, cedex 4, Aix-en-Provence, 13545 France
AU: Niemeijer, A
EM: Niemeyer@geo.uu.nl
AF: HPT Laboratory, Utrecht University, P.O. Box 80 021 Faculty of Earth Sciences, University of Utrecht, Utrecht, 3508 Netherlands
AB: Stressed water-infiltrated silica rocks deform by pervasive pressure solution transfer (PPST), which involves dissolution of the grain-to-grain contacts, transport by diffusion, and precipitation on the free surfaces of the grains. A fundamental question regarding this process concerns the modeling of its rheological behavior at stresses and temperature typical of the upper crust of the Earth. A Voigt- type poro-visco-plastic model is modified by using a Cole Cole distribution of relaxation times rather than a Dirac distribution as proposed previously. The motivation of this choice is to account for a wide distribution of grain size in the compactional process of the porous aggregate. This wide grain size distribution results from both the initial grain size distribution and cataclasis in the early stage of compaction. We compare sucessfully this modified visco-plastic model with the full set of experimental data obtained in various conditions of grain size, effective stress, and temperature by Niemeijer et al. (2002). In addition, we show that at high effective stresses (> 100 MPa), a departure of linearity between the porosity and the effective stress is clearly observed in the experimental data and can be accounted for in the compactional response of the porous aggregate.
DE: 3902 Creep and deformation
DE: 7209 Earthquake dynamics (1242)
DE: 8010 Fractures and faults
DE: 8045 Role of fluids
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
SC: Tectonophysics [T]
MN: Fall Meeting 2005