• 责任者：Wei Bo (Faculty of Earth Sciences ; China University of Geosciences ; Wuhan 430074 ; China) ; Jin Zhenmin
• 刊名：Earth Science
• 出版年：2013
• 卷期：38(5)
• 关键词：异剥橄榄岩 ; diallage peridotite ; 大别山 ; Dabie Mountains
• 页码：p.983-994
• 图表：5 illus., 3 tables, 61 refs.
• 分类号：0801
• issnNo：ISSN1000-2383
• isbnNo：CN42-1233/P

     Studies of deformed microstructures of peridotite in ultrahigh-pressure metamorphic belt are conductive to understand rheological property and deformation mechanism of mantle materials derived from plate boundary,then further to explore the effect of microstructures during geodynamic process of the deep subduction and exhumation.Deformed microstructures of garnet wehrlite from Bixiling,Dabie Mountains are systematically studied through optical microscope,electron probe,infrared spectroscopy,electron back scattered diffraction（EBSD）technique and the method of oxidation decoration.Results show that：（1）garnet wehrlite from Bixiling with strong shape preferred orientation（SPO）,but only clinopyroxene with strong lattice preferred orientation（LPO）and olivine with weak lattice preferred orientation,which is obviously different from the common characteristics of mantle peridotite which exhibits the stronger fabric in olivine than in clinopyroxene and in addition,reflects that clinopyroxene deforms through dislocation creep but olivine through grain boundary sliding with the adjustment of dislocation;（2）certain content of structural water are contained in clinopyroxene and olivine of garnet wehrlite from Bixiling,clinopyroxene with 124×10-6-247×10-6 and olivine with 38×10-6-80×10-6,which are higher than that in minerals of general peridotite in orogenic belt and may reflect the environment with high water content caused by the contamination of crust material;（3）significant dislocation microstructures developed in olivine and 230-600MPa of differential stress calculated by the dislocation microstructures which is higher than the steady flow stress of normal upper mantle and indicates that our samples once have experienced the relative low-temperature deforming environment in subduction zone.Comprehensive study shows that the relatively special deforming microstructures in olivine and clinopyroxene from Bixiling attribute to the high pressure,low temperature,high differential stress and structural water content in ultrahigh-pressure metamorphic belt.