云南香格里拉县洛吉蛇绿混杂岩中单斜辉石的矿物学特征  

Compositional characteristics of clinopyroxenes from the Luoji ophiolitic mélange in Shangri-La County, Yunnan Province

作　　者：邹金汐[1] 刘显凡[1] 邓江红[1] 董毅[1] 黄玉蓬[1] 

机构地区：[1]成都理工大学地球科学学院,四川成都610059

出　　处：《中国地质》2013年第6期1806-1817,共12页Geology in China

基　　金：中国地质调查局地调项目(1212011120587);国家公益性行业科研专项项目-系统矿物学研究(201011005-5);成都理工大学矿物学岩石学矿床学国家重点(培育)学科建设项目(SZD0407)联合资助

摘　　要：洛吉蛇绿混杂岩分布于云南香格里拉县，由镁铁质-超镁铁质堆晶岩块、辉长-辉绿岩墙群、玄武岩及条带状硅质岩等以构造混杂方式产出。岩相学研究发现其中堆晶岩块与玄武岩中单斜辉石具有相似性，矿物化学成分研究表明洛吉蛇绿混杂岩单斜辉石种属为富镁贫铁和高钙的普通辉石，其母岩浆属亚碱性系列的拉斑玄武岩浆，辉石晶体中阳离子取代特征显示其形成于高温低压的条件，辉石形成温度为986-1118℃，压力为O．18-0.22GPa，结合矿物成分和演化特征．认为该套混杂岩为甘孜-理塘蛇绿岩带残余产物。In Shangri-La County of Yunnan Province, the authors documented an ophiolitic m61ange which is composed of mafic-ultramafic cumulate rocks, diabase-gabbro dykes, basalts and banded cherts. On the basis of petrological observations and mineral compositions of clinopyroxenes from the mafic-ultramafic cumulate rocks and basalts, the clinopyrixenes were divided into two groups, one group is rich in magnesium and depleted in iron while the other group is rich in calc. Both of the two groups of clinopyroxenes belong to augites, whose parental magma was sub-alkaline tholeitic basalt. Cation substitution features indicate that the augites were formed under the condition of high temperature and low pressure. T-P calculations show that the angites were formed at 986 to 1118 ℃ and 0.18 GP to 0.22 GP. It is suggested that the Luoji m61ange is probably a part of the Garze- Litang ophiolite.

关 键 词：洛吉蛇绿混杂岩 单斜辉石 云南香格里拉 甘孜-理塘带 

分 类 号：P588.125[天文地球—岩石学]