Discovery of super-silicic and super-titanic garnets in garnet-pyroxenite in Zhaheba and its geological significance  

作　　者：NIU HeCai ZHANG HaiXiang SHAN Qiang YU XueYuan 

机构地区：[1]Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China

出　　处：《Chinese Science Bulletin》2008年第14期2186-2191,共6页

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 40673036);Chinese Academy of Sciences (Grant Nos. KZCX2-YW-107 and GIGCX-04-03)

摘　　要：Super-silicic garnet which exists stably at more than 5 GPa is a typical ultra-high pressure mineral. The super-silicic garnet and super-titanic garnet were discovered for the first time in garnet-pyroxenite of early Paleozoic Zhaheba-Aermantai orogenic belt in north Xinjiang. Our study indicates that these su- per-silicic garnets as well as super-titanic garnets were formed at a depth of at least 300 km. Their host rock―― garnet-pyroxenite is one kind of ultra-pressure metamorphic rocks which is related to the ul- tra-deep subduction of the oceanic crust. Thus, the early Paleozoic Zhaheba-Aermantai orogenic belt is related to the ultra-deep subduction of the Paleo-Asian oceanic crust.Super-silicic garnet which exists stably at more than 5 GPa is a typical ultra-high pressure mineral. The super-silicic garnet and super-titanic garnet were discovered for the first time in garnet-pyroxenlte of early Paleozoic Zhaheba-Aermantai orogenic belt in north Xinjiang. Our study indicates that these su per-silicic garnets as well as super-Utanic garnets were formed at a depth of at least 300 km. Their host rock-garnet-pyroxenite is one kind of ultra-pressure metamorphic rocks which is related to the ultra-deep subduction of the oceanic crust. Thus, the early Paleozoic Zhaheba-Aermantai orogenic belt is related to the ultra-deep aubduction of the Paleo-Aaian oceanic crust.

关 键 词：蛇纹石 辉岩 石榴石 变质作用 

分 类 号：P58[天文地球—岩石学]