塔里木西克尔基性麻粒岩捕虏体的发现及其地质意义  

Discovery of granulite xenoliths from Xikeer,Tarim,Northwest China and its geological implications

作　　者：田伟[1] 魏春景[1] 陈咪咪[1] 张贵宾[1] 

机构地区：[1]北京大学地球与空间科学学院造山带与地壳演化教育部重点实验室,北京100871

出　　处：《岩石学报》2010年第2期573-583,共11页Acta Petrologica Sinica

基　　金：国家重点基础研究发展计划(973)项目(2007CB411307);国家自然科学基金(40502009;40525006;40821002)联合资助

摘　　要：在塔里木西部新生代碧玄岩中新发现了基性麻粒岩捕虏体。其原生矿物组合为Cpx+Opx+Pl(An=30～50)+Sp+Ilm+Tim,次生矿物组合为Ol+Pl(An>50)+alkaline feldspar+glass。原生矿物组合的温度和压力分别为1005～1059℃和0.6～1.1GPa;次生矿物组合形成于近等温减压过程和固相线上熔融以及之后的近地表快速冷却。这些麻粒岩捕虏体代表了早期底侵到塔里木板块下地壳的幔源岩浆。Mafic granulite xenoliths in Cenozoic basanite were newly found in Xikeer,western Tarim Block.The primary mineral assemblage of Xikeer granulite xenoliths is Cpx + Opx + Pl(An = 30～50) + Sp + Ilm + Tim,and the secondary mineral assemblage is Ol + Pl(An>50) + alkaline feldspar + glass.The temperature and pressure of the primary mineral assemblage are 1005～1059℃and 0.6～1.1GPa.The secondary mineral assemblage is originated during isothermal decompression(ITD),supra-solidus melting as well as fast cooling near the surface.These granulite xenoliths represent a previous mantle derived magma underplate at the low crust of the Tarim block.

关 键 词：西克尔 塔里木 麻粒岩捕虏体 超高温(UHT)变质作用 底侵 

分 类 号：P588.34[天文地球—岩石学]