Coesite in the eclogite and schist of the Atantayi Valley, southwestern Tianshan, China  

作　　者：LÜ Zeng ZHANG LiFei 

机构地区：[1]Key Laboratory of the Orogenic Belt and Crustal Evolution,Ministry of Education,School of Earth and Space Sciences,Peking University,Beijing 100871,China

出　　处：《Chinese Science Bulletin》2012年第13期1467-1472,共6页

基　　金：supported by the National Natural Science Foundation of China (40730314, 41002019, and 40821002);the National Basic Research Program of China (2009CB825007);the National Science Foundation for Postdoctoral Scientists of China

摘　　要：Coesite is an indicator mineral of ultra-high-pressure metamorphism. Since coesite was reported in the Habutengsu Valley, we have also found it in eclogite and schist from the Atantayi Valley in the southwestern Tianshan, China. Petrographic and micro-Raman analyses were carried out for the Atantayi metamorphic rocks and coesite was recognized in the predominant rock types, i.e. schist and eclogite, from three sections. The coesite-bearing schist consists mainly of garnet, Na-Ca amphibole, quartz, white mica and albite; the coesite-bearing eclogite is mainly composed of omphacite, garnet, glaucophane and zoisite. The coesite occurs as various mineral inclusions within porphyroblastic garnet. Findings of coesite in eclogite and associated schist indicate not only the regional in situ formation of the Atantayi ultra-high-pressure eclogite, but also the large areal extent of ultra-high-pressure metamorphism in southwestern Tianshan, extending up to 10 km north-south and 60-80 km east-west.Coesite is an indicator mineral of ultra-high-pressure metamorphism. Since coesite was reported in the Habutengsu Valley, we have also found it in eclogite and schist from the Atantayi Valley in the southwestem Tianshan, China. Petrographic and micro-Raman analyses were carried out for the Atantayi metamorphic rocks and coesite was recognized in the predominant rock types, i.e. schist and eclogite, from three sections. The coesite-bearing schist consists mainly of garnet, Na-Ca amphibole, quartz, white mica and albite; the coesite-bearing eclogite is mainly composed of omphacite, garnet, glaucophane and zoisite. The coesite occurs as various mineral inclusions within porphyroblastic garnet. Findings of coesite in eclogite and associated schist indicate not only the regional in situ formation of the Atantayi ultra-high-pressure eclogite, but also the large areal extent of ultra-high-pressure metamorphism in southwestem Tianshan, extending up to 10 km north-south and 60-80 km east-west.

关 键 词：柯石英榴辉岩 石英片岩 西南天山 中国 超高压榴辉岩 矿物包裹体 超高压变质 变质矿物 

分 类 号：P588.125[天文地球—岩石学]