Survival of eclogite xenolith in a Cretaceous granite intruding the Central Dabieshan migmatite gneiss dome(Eastern China) and its tectonic implications
作者单位：State Key Laboratory of Lithospheric EvolutionInstitute of Geology and GeophysicsChinese Academy of Sciences
会议名称：《中国科学院地质与地球物理研究所2006学术年会》
会议日期：2007年
学科分类：070904[理学-构造地质学] 0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学]
关 键 词：Eclogite xenolith Mesozoic granite Radiometric ages Exhumation model Dabieshan China
摘 要：Investigation of an eclogite xenolith discovered in a Cretaceous granite from the Central Domain of the Dabieshan massif in eastern China yields new petrological insights on the high to ultrahigh-pressure metamorphism experienced by the Qinling-Dabie *** to inclusion as a xenolith in the granite during the Early Cretaceous,this eclogite xenolith had recorded a complex metamorphic evolution that complies with subduction and exhumation processes experienced by the continental crust of the South China ***- preserved mineral parageneses substantiate the prograde and retrograde stages revealed by inclusions in porphyroblastic garnet and zoned minerals such as garnet,omphacite and amphibole in the matrix. The relatively low P/T re- equilibration during a late metamorphic stage was textually inferred by the presence of aluminous and calcic-subcalcic amphiboles such as katophorite,edenite,taramite and pargasite as main matrix *** to our U/Pb,Rb/Sr and new 40Ar/39Ar geochronological results,namely 109±1 Ma and 112±2 Ma plateau ages for muscovite and amphiboles,respectively,two successive but distinct cooling stages account for the thermal history of the granite- migmatite gneiss dome that forms the Central Dabieshan *** argue that prior to the Cretaceous doming,the Central Dabieshan Domain experienced a tectono-metamorphic evolution similar to that observed in the high-pressure to ultra high-pressure units developed in the Southern Dabieshan Domain and Hong ’an massif.