滇西腾冲-梁河地区老厂坡、大竹棚和来利山花岗岩的黑云母成分特征及其成岩成矿意义  

Biotite composition of Laochangpo,Dazhupeng and Lailishan granite in Tengchong-Lianghe region of western Yunnan,and its petrogenetic and metallogenetic significance

作　　者：李昊星 张寿庭[1] 曹华文[2] 裴秋明 胡昕凯 王亮[1] LI Hao-xing;ZHANG Shou-ting;CAO Hua-wen;PEI Qiu-ming;HU Xin-kai;WANG Liang(School of the Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;Chengdu Center,China Geological Survey,Chengdu 610081,China;Faculty of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu 611756,China)

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]中国地质调查局成都地质调查中心,成都610081 [3]西南交通大学地球科学与环境工程学院,成都611756

出　　处：《桂林理工大学学报》2020年第4期665-676,共12页Journal of Guilin University of Technology

基　　金：国家“十二五”科技支撑计划项目(2011BAB04B06);中国地质调查局项目(1212011220925);中央高校基本科研业务费专项(2652014112)。

摘　　要：滇西腾梁地区花岗岩与锡矿床在成因上密切相关。通过对来利山花岗岩、大竹棚花岗岩及老厂坡花岗岩进行岩相学观察与黑云母的化学成分特征分析,探讨黑云母的形成条件及其成岩成矿意义。电子探针测试结果表明,三处岩体中黑云母均具有富铁贫镁的特征;来利山岩体和大竹棚岩体中黑云母为铁叶云母,结晶温度分别为629~691℃和603~635℃,氧逸度分别为-15.9^-18.0和-17.6^-18.7,指示岩体为S型花岗岩;老厂坡岩体中的黑云母属铁质黑云母,结晶温度为718~749℃,氧逸度-13.7^-14.8,指示岩体为具有部分幔源物质混染的S型花岗岩,表明本区接近纯地壳物质部分熔融形成的S型花岗岩在低温低氧逸度条件下有利于锡矿形成。相较于老厂坡岩体,来利山岩体及大竹棚岩体成矿潜力更大。The granites in Tengchong-Lianghe region of western Yunan are closely associated with the tin mineralization in genesis.Based on the research of the petrography observation and characteristic analysis of the biotites chemical composition from Lailishan,Dazhupeng and Laochangpo granite plutons,this article discusses the biotite forming conditions and petrogenesis and mineralization.Electron microprobe analysis(EPMA)shows that the biotites from three plutons are rich in Fe and depleted in Mg.Biotites from Lailishan granite and Dazhupeng granite belong to siderophyllite,while biotite from Laochangpo granite belongs to ferro biotite.These characteristics implicate that Lailishan granite,Dazhupeng granite and Laochangpo granite belong to S-type granite,whereas Laochangpo granite is the result of the mixing of crust and a modicum of mantle derived magmas.The crystallization temperatures of biotites from Lailishan granite and Dazhupeng granite are 629-691℃and 603-635℃respectively,with the oxygen fugacities log fO2 of-15.9 to-18.0 and-17.6 to-18.7 respectively.The crystallization temperature of biotite from Laochangpo granite is 718-749℃,with the oxygen fugacity log fO2 of-13.7 to-14.8.Based on the analysis,the granite derived from the partial melts of nearly pure sedimentary materials in crust,with relatively low temperature and low oxygen fugacity,is favorable for the mineralization of Sn.Lailishan granite and Dazhupeng granite are more conducive to the formation of Sn deposits and have a higher potential for Sn mineralization than Laochangpo granite.

关 键 词：黑云母 成分特征 花岗岩 成岩成矿 腾冲-梁河地区 滇西 

分 类 号：P578.959[天文地球—矿物学] P574.2[天文地球—地质学]