HR: 11:20h
AN: V41E-05    [PDF]
TI: Relaxation flow law of Fe$_{2}$SiO$_{4}$ olivine and spinel at high pressure: A stress and strain measurement using x-rays
AU: * Chen, J
EM: Jiuhua.Chen@sunysb.edu
AF: Mineral Physics Institute, State University of New York, ESS Bldg. SUNY SB, Stony Brook, NY 11794-2100 United States
AU: Li, L
EM: llili@ic.sunysb.edu
AF: Mineral Physics Institute, State University of New York, ESS Bldg. SUNY SB, Stony Brook, NY 11794-2100 United States
AU: Weidner, D
EM: Donald.Weidner@sunysb.edu
AF: Mineral Physics Institute, State University of New York, ESS Bldg. SUNY SB, Stony Brook, NY 11794-2100 United States
AU: Vaughan, M
EM: Michael.Vaughan@sunysb.edu
AF: Mineral Physics Institute, State University of New York, ESS Bldg. SUNY SB, Stony Brook, NY 11794-2100 United States
AB: Synchrotron x-rays have become an extremely compelling tool in studying material properties under high pressures. In addition to exploring means to reveal the information of material properties that is not obtainable before, developments using synchrotron x-rays have also enabled many reformations of traditional experiments. In this report, we present the results of stress and strain measurement at high pressures and temperatures using synchrotron x-ray diffraction and radiograph imaging techniques. For the first time, rheological properties of both the low pressure phase (olivine) and the high pressure phase (spinel) of Fe$_{2}$SiO$_{4}$ sample are derived from a single experiment. A clear strengthening in the material due to the phase transformation is observed. The stress and strain rate data measured at temperatures up to 1075K are used to derive the Periels plasticity flow law ($\varepsilon'$=$\varepsilon'$$_{0}$exp(-$\frac{Q}{RT}$(1-$\frac{\sigma}{\tau}$)$^{2})$) for each phase, and yield an activation energy and Periels stress of 480$\pm$20 kJ/mol and 6.7$\pm$0.5 GPa for olivine phase and 460$\pm$20 kJ/mol and 6.5$\pm$0.5GPa for spinel phase. Compared with existing data for San Carlos olivine, a significant weakening by increasing iron content in the structure is revealed. Technical details and data processing for the experiment will be discussed.
DE: 3900 MINERAL PHYSICS
DE: 3902 Creep and deformation
DE: 3924 High-pressure behavior
DE: 3954 X ray, neutron, and electron spectroscopy and diffraction
DE: 5120 Plasticity, diffusion, and creep
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting