Experimental Investigation of the Creep Behavior of Garnet at High Temperatures and Pressures  

作　　者：Shenghua Mei Ayako M Suzuki David L Kohlstedt 许丽丽 

机构地区：[1]Department of Geology and Geophysics, University of Minnesota, MN 55455, USA [2]Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China

出　　处：《Journal of Earth Science》2010年第5期532-540,共9页地球科学学刊（英文版）

基　　金：supported by the US Department of Energy, Office of Basic Energy Sciences (No. DE-FG02-04ER15500);National Science Foundation (No. NSF-EAR-0652852)

摘　　要：To provide constraints on the rheological properties of garnet, we have experimentally investigated the creep behavior of garnet at high pressures and temperatures using a deformation-DIA. Samples were cold-pressed from a garnet powder and deformed at constant displacement rates ranging from 1.1×10^-5 to 2.6×10^- s^-1 at high temperatures （1 273-1 473 K） and high pressures （2.4-4.1 GPa）. Differential stress and pressure were measured using X-ray diffraction techniques based on the elastic strain of various lattice planes as a function of orientation with respect to the applied stress field. The plastic strain of a deforming sample was monitored in-situ through a series of radiographs. Our results provide a measure of the dependence of creep rate of garnet on the temperature with an activation energy of -280 kJ/mol and on pressure with an activation volume of -10×10^-6 m3/mol. The flow behavior of garnet quantified by this study provides the basis for modeling geodynamic processes occurring within subducted lithosphere.To provide constraints on the rheological properties of garnet, we have experimentally investigated the creep behavior of garnet at high pressures and temperatures using a deformation-DIA. Samples were cold-pressed from a garnet powder and deformed at constant displacement rates ranging from 1.1×10^-5 to 2.6×10^- s^-1 at high temperatures （1 273-1 473 K） and high pressures （2.4-4.1 GPa）. Differential stress and pressure were measured using X-ray diffraction techniques based on the elastic strain of various lattice planes as a function of orientation with respect to the applied stress field. The plastic strain of a deforming sample was monitored in-situ through a series of radiographs. Our results provide a measure of the dependence of creep rate of garnet on the temperature with an activation energy of -280 kJ/mol and on pressure with an activation volume of -10×10^-6 m3/mol. The flow behavior of garnet quantified by this study provides the basis for modeling geodynamic processes occurring within subducted lithosphere.

关 键 词：GARNET CREEP LITHOSPHERE GEODYNAMICS high pressure. 

分 类 号：O484.1[理学—固体物理] TQ342.72[理学—物理]