青藏高原西部蛇绿岩中玻安岩(boninite)及其地质意义  

BONINITE OF OPHIOLITE BELTS IN WESTERN QINGHAI-TIBET PLATEAU AND ITS GEOLOGICAL IMPLICATION

作　　者：邱瑞照[1] 蔡志勇[2] 李金发[3] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国科学院广州地球化学研究所,广东广州510640 [3]中国地质大学资源学院,湖北武汉430074

出　　处：《现代地质》2004年第3期305-308,共4页Geoscience

基　　金：中国地质调查局地质调查项目(200110200064);国土资源部科技计划专项及"中国三维岩石圈深部物质模型研究"课题(200010103);中国地质大学"岩石圈构造;深部过程及探测技术"教育部重点实验室开放课题(2003010)。

摘　　要：简要报道了在青藏高原西部班公湖蛇绿岩带和狮泉河蛇绿岩带之间的火山岩中识别出的玻安岩。玻安岩是俯冲岩浆作用的产物,在青藏高原东部及周边地区已有玻安岩或玻安岩系岩石存在的报道,结合西部出现的玻安岩说明青藏高原地区俯冲作用普遍存在。玻安岩的形成时代为J2—K1,埃达克岩的形成时代为K1,由J2—K1的玻安岩至K1的埃达克岩反映冈底斯北部岛弧带由不成熟的洋内弧向成熟岛弧转变的过程,它们是中生代冈底斯北部大陆水平生长(侧向增生)的记录。Boninite, which distinguished from the volcanic rocks between Bangonghu and Shiquanhe ophiolite belts, has been briefly reported in this paper. Boninite was regarded as the products of subduction magmatism, boninite or boninite series rocks distributed widely in the east, west, and surrounding areas of Qinghai-Tibet Plateau indicated the subduction has ever been undergone commonly. The age of boninite is from Middle Jurassic to Early Cretaceous, and the adakite is in Cretaceous. The occurrences of boninite to adakite rocks indicate the changing process of immature inner-oceanic island to mature island in North Gangdese, and the rocks of boninite and adakite are the petrological records of continental level growth in Mesozoic.

关 键 词：玻安岩 俯冲岩浆作用 地质意义 青藏高原西部 

分 类 号：P58[天文地球—岩石学]