羌塘地区榴辉岩中矿物出溶体及其成因机制探讨  

Mineral Exsolution and its Genetic Significance of the Songduo-Qiangtang Eclogite in Qinghai-Tibet

作　　者：武海[1,2] 董亚林[1,3] 许瑞梅[3] 赵文霞[3] WU Hai DONG Yalin XU Ruimei ZHAO Wenxia(School of Earth Science and Geological Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, China Hongshi Holding Group Co., Ltd, Jinhua 321100, Zhejiang, China Instrumental Analysis and Research Center, Sun Yat-sen University, Guangzhou 510275, Guangdong, China)

机构地区：[1]中山大学地球科学与地质工程学院,广东广州510275 [2]红狮控股集团有限公司,浙江金华321100 [3]中山大学测试中心,广东广州510275

出　　处：《大地构造与成矿学》2016年第5期975-985,共11页Geotectonica et Metallogenia

基　　金：国家自然科学基金(41273039)资助

摘　　要：西藏羌塘地区榴辉岩石榴子石和磷灰石中均发育矿物出溶体,结合电子探针和扫描电镜分析及能谱分析,确定了石榴子石中的出溶体有金红石、石英和角闪石,指示其可能经历了高压/超高压变质作用。本研究在磷灰石中发现了金红石出溶,并认为其可能是在高压/超高压条件下元素相互置换的结果,置换方式为Ti^(4+)(Fe^(2+)、Si^(4+))=2Ca^(2+),这些出溶体的形成为榴辉岩曾经历高压/超高压变质作用提供了矿物学证据。Recent studies have shown that garnet and apatite with needle-like exsolution lamellae are widely found in the eclogites from the central Qiangtang metamorphic belt. Needle-like exsolution lamellae of rutile, quartz and amphibole are identified in garnet and apatite by electron microprobe（EPMA）, scanning electron microscope（SEM） and X-ray energy-dispersive（EDS） analyses. The garnet may have experienced HP/UHP metamorphism. We find for the first time apatite with exsolution of rutile that may have been formed by the replacement of Ti^（4＋）（Fe^（2＋）, Si^（4＋））=2Ca^（2＋） under high pressure or ultra-high pressure conditions. These exsolution lamellae in garnet and apatite imply that the Qiangtang eclogite may have experienced HP/UHP metamorphism.

关 键 词：青藏羌塘 HP/UHP榴辉岩 出溶结构 超高压变质 

分 类 号：P581[天文地球—岩石学]