青海祁漫塔格虎头崖铅锌多金属矿区年代学研究及地质意义  

Isotopic Chronology of the Hutouya Skarn Lead-Zinc Polymetallic Ore District in Qimantage Area of Qinghai Province and Its Geological Significance

作　　者：丰成友[1,2] 王雪萍 舒晓峰 张爱奎 肖晔[2] 刘建楠[2] 马圣钞[2] 李国臣[2] 李大新[2] 

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]中国地质科学院矿产资源研究所/国土资源部成矿作用与资源评价重点实验室,北京100037 [3]青海省核工业地质局,西宁810008 [4]青海省第三地质矿产勘查院,西宁810029

出　　处：《吉林大学学报（地球科学版）》2011年第6期1806-1817,共12页Journal of Jilin University：Earth Science Edition

基　　金：中央级公益性科研院所基本科研业务费专项资金项目(K0901);国土资源部'百人计划'项目(200809);中国地质调查局地质调查项目(1212011085528;1212011120135);中国博士后科学基金项目(20090460132);'十一.五'国家科技支撑计划课题(2006BAB01A06)

摘　　要：虎头崖铅锌多金属矿是青海祁漫塔格地区较为典型的兼具正接触带矽卡岩亚型和外接触带矽卡岩亚型的接触交代型矿床。笔者对其开展了详细的地质特征解剖和高精度成岩成矿年代学研究,结果表明:矿区金属成矿元素组合复杂,矿化主要产于侵入体与围岩接触带、不同时代地层间的断裂带或不整合面及不同岩性界面,自成矿岩体内部向外具有明显的金属矿化与蚀变分带。利用锆石LA-ICP-MS和SHRIMP U-Pb法,获得成矿花岗闪长岩体和二长花岗岩体的成岩年龄分别为(235.4±1.8)Ma(n=24,MSWD=1.7)和(219.2±1.4)Ma(n=11,MSWD=0.83);利用辉钼矿Re-Os法,获得矽卡岩型铜钼多金属矿石和矽卡岩型钼矿石的等时线年龄分别为(225.0±4.0)Ma(n=7,MSWD=0.24)和(230.1±4.7)Ma(n=5,MSWD=0.12),厘定矿区成岩成矿时代为中—晚三叠世。综合青海祁漫塔格地区已有年代学资料和区域地质构造演化特征,认为该区印支期大规模岩浆侵入活动和多金属成矿作用形成于后碰撞构造阶段,为区域东昆仑造山带晚古生代—早中生代构造旋回的产物。Located in Qimantage area of Qinghai Province,Hutouya is a typical skarn lead-zinc polymetallic ore district consisting of both ortho-contact and exocontact substyles.The basic geological characteristics and ages of petrogenesis and mineralization were studied.The ore-forming elements are quite complex,dominated by Fe,Cu,Sn,Mo,Pb and Zn.Mineralization occurs in the contact zone between the intermediate-acidic intrusive rock and the carbonate-bearing strata,the fault zone or discordant contact between strata of different epochs and the lithologic boundaries,showing obvious zonation of mineralization and alteration from the intrusive rock outwards.U-Pb dating of zircons from granodiorite and adamellite has yielded ages of（235.4±1.8） Ma and（219.2±1.4） Ma,respectively.Re-Os isotopic dating of molybdenite from the skarn Cu-Mo polymetallic ore and skarn molybdenite ore by ICP-MS has yielded isochron ages of（225.0±4.0） Ma and（230.1±4.7） Ma.These new age data,combined with data available,indicate that the ages of ores and related granites should be Middle to Late Triassic.Indosinian magmatism and mineralization occurred at the post-collisional stage of the orogen,corresponding to the late stage of the Late Paleozoic-Early Mesozoic tectonic event in eastern Kunlun orogenic belt.

关 键 词：矽卡岩型多金属矿 锆石U-PB测年 RE-OS同位素测年 同位素 虎头崖 祁漫塔格 东昆仑 

分 类 号：P618.67[天文地球—矿床学]