北天山西段喇嘛苏铜矿中酸性岩体岩石化学特征及其地质意义  

Petrochemical Characteristics and Its Geological Significance of the Acid-intermediate Intrusive Bodies in Lamasu Copper Deposit in the western section of north Tianshan Mountain

作　　者：毛政利 成功[2,3] 赖健清[2,3] 彭省临[2,3] MAO Zhengli;CHENG Gong;LAI Jianqing;PENG Shenglin(School of Management Science and Engineering,Baise University,Baise 533000,Guangxi,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals,Ministry of Education,Central South University,Changsha 410083,China;School of Geosciences and Info-Physics,Central South University,Changsha 410083,China)

机构地区：[1]百色学院管理科学与工程学院,广西百色533000 [2]中南大学有色金属成矿预测教育部重点实验室,长沙410083 [3]中南大学地球科学与信息物理学院,长沙410083

出　　处：《地质找矿论丛》2018年第1期93-99,共7页Contributions to Geology and Mineral Resources Research

基　　金：国家自然科学基金项目(编号:41171342)资助

摘　　要：喇嘛苏铜矿区中酸性岩体的皮科克指数、里特曼指数、赖特指数,均指示其中酸性岩体属于钙碱性岩系的范围;分异指数平均值为77.57,说明岩体的分异演化程度较为彻底;固结指数平均值为12.01,显示出岩体的岩浆分异程度较高;长英指数和铁镁指数均反映岩体的分离结晶作用程度中等。在MF—FL分异趋势图上,样品点基本呈连续分布,说明岩体的演化是连续的;在w(Na_2O)—w(K_2O)关系图上多数样品点落入I型花岗岩区域,可以认为本区花岗岩应为I型花岗岩。岩体的TiO_2含量平均为w(TiO_2)=0.28%,远低于中国及世界同类岩石;在戈蒂尼指数与里特曼指数对数值的关系图上,几乎所有的样品点均落在消减带火山岩区,由此可以推断,本区斑岩体应形成于与俯冲作用有关的消减带上。在多阳离子的R1—R2关系图中,多数样品点落在地壳熔融花岗岩-同碰撞的花岗岩区,少数样品点落在其它区域,这说明了岩浆在演化过程中同化混染了围岩。Peacock index,Rittmann index and Wright index of the acid-intermediate intrusive bodies in Lamasu copper deposit all indicate that the acid-intermediate intrusive bodies in this area belong to calc-alkalic rock series.The average of differentiation index is77.57showing their relatively complete differentiation evolution;the average of solidification index is12.01showing relatively high magmatic differentiation;the average of felsic index is69.96and mafic index61.98showing the medium degree of fractional crystallization.On MF FL differentiation trend chart,distribution of sample point basically is continuous illustrating their continuous evolution.Most sample points on Na20vs K20relational diagram fall into the area of I-type granite reflecting that the intrusive bodies are I-type granite.The average content of Ti02of the intrusive bodies are0.28%far below those of the same kind of rocks in other areas of China and other places of the World.On the relational chart of lgr-lga,almost all of the sample points fall into the area of volcanic rock of subduction zone.All this indicates that the intrusive bodies should be formed in subduction zone and they related with subduction process.On the relational chart of R1vs R2,most of the sample points fall into the area of crustal molten granite and syn-collisional granite,and a few sample pointsl into other areas illustrating assimilation and blending with country rock during the evolution of magama.

关 键 词：喇嘛苏铜矿 中酸性岩体 结晶环境 分异演化 消减带 北天山西段 新疆 

分 类 号：P588.1[天文地球—岩石学]