摘要
岩湾-鹦鸽咀蛇绿混杂岩是秦岭商丹蛇绿混杂岩带的重要组成部分,由变质基性火山岩(玄武岩)、蛇纹岩、变辉长岩、硅质岩、变复理石(云母石英片岩)等构造岩块组成。其中变基性火山岩具有N-MORB的地球化学特征,安山岩具有与俯冲作用密切相关的岛弧火山岩的性质。玄武岩的锆石SHRIMP U-Pb年龄为483Ma±13Ma,与天水关子镇和丹凤蛇绿混杂岩的时代相一致。对岩湾-鹦鸽咀蛇绿混杂岩的岩石组成和形成时代进行研究,可为进一步探讨商丹蛇绿混杂岩带和秦岭造山带的增生造山作用提供重要证据。
The Yanwan-Yinggezui ophiolidc melange in the West Qinling orogenic belt is an important component part of the Shangdan ophiolidc m61ange. It is composed of tectonic blocks of metabasic volcanic rocks （basalt）, serpentinite, metagabbm, cherts and meta-flysch （mica-quartz schist）, of which basalt blocks have the geochemical features of N-MORB and andesite is subducdon- related island-arc rocks. The zircon SHRIMP U-Pb age of basalt is 483±13 Ma, which agrees with the age of the Guanzizhen and Danfeng ophiolitic melanges. The study of the composition and age of the Yanwan-Yinggezni ophiolitic melange can provide important geological evidences for a further study of the evolution of the Shangdan ophiolitic melange and accredonary orogeny of the Qinling orogenic belt.
出处
《地质通报》
CAS
CSCD
北大核心
2008年第4期500-509,共10页
Geological Bulletin of China
基金
国家自然科学基金项目(编号:40773044)
国家科技支撑计划项目(编号:2006BAB01A11)
中国地质调查局国土资源调查研究项目(编号:1212010610319、1212010611807)共同资助
