西天山卡特巴阿苏大型金铜矿赋矿二长花岗岩岩石学、元素组成和时代  

Petrology,geochemistry and zircon U-Pb isotope chronology of monzogranite of the Katbasu Au-Cu deposit,western Tianshan,Xinjiang Province

作　　者：冯博[1,2] 薛春纪[1,2] 赵晓波[1,2] 丁振信[1,2] 张祺[1,2] 俎波[1,2] 杨维忠[3] 林泽华[3] 陈威[3] 

机构地区：[1]地质过程与矿产资源国家重点实验室 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]新疆维吾尔自治区地质矿产勘查开发局第一区域地质调查大队,新疆乌鲁木齐830011

出　　处：《地学前缘》2014年第5期187-195,共9页Earth Science Frontiers

基　　金：国家科学支撑计划项目(2011BAB06B02);国家自然科学基金项目(U1303292);中国地质调查工作项目(1212011220926)

摘　　要：新疆西天山新发现的卡特巴阿苏大型金铜矿床赋矿岩石主体为二长花岗岩。对容矿的二长花岗岩进行岩石学、地球化学及锆石U-Pb法年代学研究表明,岩石形成于伊犁—中天山地块南缘隆起带,主要由钾长石、斜长石（An=20）、石英和少量黑云母组成,中粗粒花岗结构,块状构造;岩石富钾（K2O/Na2O=0.82～1.16）,A/CNK=0.85～1.09,镁值较高（Mg#=58.22～64.26）,主体属高钾钙碱性岛弧岩浆系列,具I型花岗岩特征。锆石U-Pb法测得二长花岗岩（345.5±2.6）Ma（MSWD=1.19,n=24）的成岩年龄,反映早石炭世侵位,应是南天山洋向北俯冲在伊犁—中天山地块南缘活动大陆边缘形成的岛弧岩浆侵入体,岩浆可能为南天山洋俯冲洋壳部分熔融产物。The ore-bearing rock of the large Au-Cu ore deposit of Katbasu which was recently discovered in Western Tianshan is the monzogranite. The studies of petrology, geochemistry and zircon U-Pb isotope chronology of the monzogranite indicate that it occurred in the Middle Tianshan uplift zone that is in the south margin of the Yili-Central Tianshan Plate. The monzogranite is mainly composed of K-feldspar, plagioclase （An=20）, quartz, biotile and a small amount of mafic minerals and has the medium-coarse granitic texture and massive structure. It belongs to high-potassium calc-alkali granitic series formed in an island-arc environment and has the characteristics of I-type granite： K-rich （K20/Na2 O= 0. 82 - 1. 16）, （A/CNK= 0. 85 - 1.09）, high Mg#（Mg#=58. 22 - 64.26）. The LA-ICP-MS U-Pb dating of zircons from granite yielded an age of （345.5 ± 2.6） Ma （MSWD= 1.19, n： 24） indicating the early Carboniferous invasion. The monzogranite is an arc magma located in the south margin of active continental margins, which was formed by the South Tianshan Ocean crust subduction under the Yili-Central Tianshan Plate and probably the partial melting of the South Tianshan Ocean crustal rocks.

关 键 词：二长花岗岩 容矿岩石 大型金铜矿 卡特巴阿苏 新疆西天山 

分 类 号：P618.51[天文地球—矿床学] P618.41[天文地球—地质学]