Discovery of eclogite inclusions and its geological significance in early Jurassic intrusive complex in Xuzhou-northern Anhui, eastern China  

作　　者：Wenliang Xu Dongyan Wang Xiaochun Liu Qinghai Wang Jingqian Lin 

出　　处：《Chinese Science Bulletin》2002年第14期1212-1216,共5页

基　　金：This work was supported by the National Natural Science Foundation of China (Grant Nos. G40172030 and G49733110).

摘　　要：The early Jurassic intrusive complex is chiefly made of monzodioritic porphyry in northern Anhui and northern Jiangsu, which emplaced in 191 Ma. The intrusive complexes contain a lot of eclogite inclusions which belong to eclogite and garnet-pyroxenite. The inclusions had undergone eclogite facies high-pressure metamorphism and am-phibolite facies retrogressive metamorphism. The garnets in eclogite inclusions are mainly almandine varieties and clino-pyroxenes are omphacite and augite. The mineral assemblage and P-T estimation results show that P-T conditions of eclogite facies metamorphism and amphibolite facies retrogressive metamorphism are over 1.2-1.5 GPa, 709-861°C and 0.7-1.03 GPa, 666-738°C, respectively. The discovery of the high-pressure xenoliths not only is of important significance to understand the composition and structure of deep crust in southern edge of North China Platform, but also can be of important influence on realizing the subduc-tion-collision-exhumation evolutional processThe early Jurassic intrusive complex is chiefly made of monzodioritic porphyry in northern Anhui and northern Jiangsu, which emplaced in 191 Ma. The intrusive complexes contain a lot of eclogite inclusions which belong to eclogite and garnet-pyroxenite. The inclusions had undergone eclogite facies high-pressure metamorphism and amphibolite facies retrogressive metamorphism. The garnets in eclogite inclusions are mainly almandine varieties and clinopyroxenes are omphacite and augite. The mineral assemblage andP-T estimation results show thatP-T conditions of eclogite facies metamorphism and amphibolite facies retrogressive metamorphism are over 1.2–1.5 GPa, 709–861°C and 0.7–1.03 GPa, 666–738°C, respectively. The discovery of the high-pressure xenoliths not only is of important significance to understand the composition and structure of deep crust in southern edge of North China Platform, but also can be of important influence on realizing the subduction-collision-exhumation evolutional process of the Dabie-Sulu ultrahigh-pressure (UHP) metamorphic belt.

关 键 词：Xuzhou-northern ANHUI region early JURASSIC INTRUSIVE complex ECLOGITE inclusion geological significance. 

分 类 号：P534[天文地球—古生物学与地层学]