Dislocation Creep Accommodated by Grain Boundary Sliding in Dunite

doi:10.1007/s12583-010-0113-1

CORC > 北京大学 > 地球与空间科学学院

	Dislocation Creep Accommodated by Grain Boundary Sliding in Dunite
	Wang, Zhongyan ; Zhao, Yonghong ; Kohlstedt, David L.
刊名	journal of earth science
	2010
关键词	grain boundary sliding creep olivine flow law SUPERPLASTIC FLOW PLASTIC-DEFORMATION CALCITE ROCKS UPPER-MANTLE OLIVINE WATER RHEOLOGY SIZE LITHOSPHERE REGIME
DOI	10.1007/s12583-010-0113-1
英文摘要	To investigate the role of grain boundary sliding during dislocation creep of dunite, a series of deformation experiments were carried out under anhydrous conditions on fine-grained (similar to 15 mu m) samples synthesized from powdered San Carlos olivine and powdered San Carlos olivine+1.5 vol.% MORB. Triaxial compressive creep tests were conducted at a temperature of 1 473 K and confining pressures of 200 and 400 MPa using a high-resolution, gas-medium deformation apparatus. Each sample was deformed at several levels of differential stress between 100 and 250 MPa to yield strain rates in the range of 10(-6) to 10(-4) s(-1). Under these conditions, the dominant creep mechanism involves the motion of dislocations, largely on the easy slip system (010)[100], accommodated by grain boundary sliding (gbs). This grain size-sensitive creep regime is characterized by a stress exponent of n=3.4 +/- 0.2 and a grain size exponent of p=2.0 +/- 0.2. The activation volume for this gbs-accommodated dislocation creep regime is V*=(26 +/- 3)x10(-6) m(2).mol(-1). Comparison of our flow law for gbs-accommodated dislocation creep with those for diffusion creep and for dislocation creep reveals that the present flow law is important for the flow of mantle rocks with grain sizes of <100 mu m at differential stresses >20 MPa. Hence, gbs-accommodated dislocation creep is likely to be an important deformation mechanism in deep-rooted, highly localized shear zones in the lithospheric upper mantle.; Geosciences, Multidisciplinary; SCI(E); 9; ARTICLE; 5,SI; 541-554; 21
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/242927]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Wang, Zhongyan,Zhao, Yonghong,Kohlstedt, David L.. Dislocation Creep Accommodated by Grain Boundary Sliding in Dunite[J]. journal of earth science,2010.
APA	Wang, Zhongyan,Zhao, Yonghong,&Kohlstedt, David L..(2010).Dislocation Creep Accommodated by Grain Boundary Sliding in Dunite.journal of earth science.
MLA	Wang, Zhongyan,et al."Dislocation Creep Accommodated by Grain Boundary Sliding in Dunite".journal of earth science (2010).