西藏申扎县甲岗雪山钨钼(铋)多金属矿床的Re-Os同位素年龄及其意义  

RE-OS ISOTOPIC AGES OF TUNGSTEN-MOLYBDENUM (BISMUTH) POLY-METALLIC ORE DEPOSIT IN THE JIAGANG SNOWY MOUNTAIN,SHENZHA COUNTY,TIBET AND THE IMPLICATIONS

作　　者：王治华[1] 王科强[1] 喻万强[1] 黄辉[1] 吴兴泉[2] 

机构地区：[1]武警黄金地质研究所,河北廊坊065000 [2]武警黄金第十二支队,四川成都610059

出　　处：《安徽地质》2006年第2期112-115,119,共5页Geology of Anhui

基　　金：国土资源大调查项目(项目编号:资[2003]003-01)资助。

摘　　要：冈底斯成矿带是西藏重要的多金属成矿区之一,在该成矿带北部申扎县首次发现的甲岗雪山钨、钼、铋多金属矿床是不同于其南部斑岩型铜多金属矿床的成矿新类型,该矿床的发现是藏北地区内生金属矿找矿的重要突破。文章首次对甲岗雪山钨、钼(铋)多金属矿床的辉钼矿进行了Re-Os同位素精确定年。矿区辉钼矿的模式年龄为(21．37±1．35)Ma。控矿岩体二长花岗岩的U-Pb同位素年龄22．22Ma,矿床的成矿年龄稍晚于岩体的发育时限。据此作者认为甲岗雪山钨、钼、铋多金属矿床是在大陆碰撞后陆内伸展构造背景下,形成于喜马拉雅中期中酸性岩浆活动阶段,矿质主要源自岩浆,矿床类型为石英大脉型。甲岗雪山钨、钼、铋、铜、铅、锌等多金属矿化是冈底斯成矿带北部昂孜错-崩纳藏布-甲岗雪山-色日荣成矿亚带最重要的一次成矿事件。The Gangdisi metallogenetic belt is one of the important poly-metallic ore-forming belts in Tibet. The tungsten-molybdenumbismuth poly-metallic ore deposit first found in the Jiagang snowy mountain of Shenzha county in the northern part of the belt is of a new type of deposit different from porphyry-type copper poly-metallic deposit in the southern part of it. Discovery of this deposit is a significant breakthrough in prospecting of endogenetic deposit in North Tibet. This paper for the first time gives a precise Re-Os isotopic dating （model age 21.37 ± 1.35 Ma） of molybdenite in the deposit. The U-Pb isotopic age is 22.22Ma for the ore-control intrusion adamellite. Ore formation of the deposit is somewhat later than development of the rock body. For this the authors argue that the deposit formed in intracontinental extensional environment after continental collision at the middle Himalayan stage when intermediate-acid magma was active, the ore matter was mainly sourced from magma and the deposit is of big quartz vein type. Mineralization of W, Mo, Bi, Cu, Pb, Zn and so on in the snowy mountain Jiagang is the most important ore-forming event at the metallogenetic sub-belt Angzicuo-Bengnazangbu- Jiagang snowy mountain-Serirong in the northern Gangdisi metallogenetic belt.

关 键 词：钨 钼(铋)多金属矿床 RE-OS同位素 模式年龄 二长花岗岩 申扎 西藏 

分 类 号：P618[天文地球—矿床学]