安徽省金寨县沙坪沟钼矿辉钼矿Re-Os年龄--兼论东秦岭-大别山中生代钼成矿作用期次划分  

Molybdenite Re-Os isotopic age of Shapinggou Mo deposit in Anhui Province and Mesozoic Mo ore-forming stages in East Qinling-Dabie Mountain region

作　　者：黄凡[1] 王登红[1] 陆三明[2] 陈毓川[3] 王波华[4] 李超[1] 

机构地区：[1]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 [2]安徽省公益性地质调查管理中心,安徽合肥230001 [3]中国地质科学院,北京100037 [4]安徽省地质矿产勘查局313地质队,安徽六安237010

出　　处：《矿床地质》2011年第6期1039-1057,共19页Mineral Deposits

基　　金：中央级公益性科研院所基本科研业务费专项资金(编号:K1022);全国矿产资源潜力评价项目(编号:1212010633901);安徽省公益性地质科技项目秦岭-大别山造山带东段(安徽部分)钼金多金属成矿规律与找矿方向研究(编号:2009-19)的联合资助

摘　　要：安徽省金寨县沙坪沟钼矿是新发现的超大型斑岩型钼矿床。文章介绍了该矿床的基本地质特征,并对其进行了精确的辉钼矿Re-Os同位素年代学测定。结果表明,沙坪沟钼矿辉钼矿模式年龄为(112.2±1.7)^(113.9±1.7)Ma,加权平均年龄为(113.18±0.54)Ma,MSWD=0.39;等时线年龄为(113.21±0.53)Ma,MSWD=0.64,表明沙坪沟钼矿形成于早白垩世晚期。结合区域上已有的岩体高精度年代学数据、矿床辉钼矿Re-Os年代学数据和钼矿产出的大地构造位置,将东秦岭-大别山中生代钼成矿作用划分为2期4个阶段:印支期(260~205Ma)和燕山期的晚侏罗世—早白垩世早期(148~138 Ma),早白垩世中期(135~119 Ma)和早白垩世晚期(116~105Ma),其中,以燕山期钼成矿作用最为强烈。The Shapinggou Mo deposit, located in Jinzhai Country of Anhui Province, is a giant ore deposit discovered in recent years in the Dabie Mountain. This paper describes geological characteristics of the ore deposit. The authors chose nine molybdenite-bearing samples for Re-Os isotopic dating, and the dating results show that the Re- Os model ages of the ore deposit are between （112.2 ± 1.7） Ma and （113.9 ± 1.7）Ma, and the calculated isochron age is （113.21 ± 0.53） Ma, suggesting that molybdenum mineralization occurred in the late period of early Cretaceous. High-precision chronologic data of regional intrusions, Re-Os dating data of molybdenites and geotectonic location of Mo deposits indicate that there occurred 2 epochs comprising 4 stages of Mo mineralization during the Mesozoic period in East Qinling-Dabie Mountain region. These Mo ore-forming stages include 205 260 Ma of Indosinian period, and 148--138 Ma, 135--119 Ma and 116--105 Ma of Yanshanian period. The Mo mineralization during the late Yanshanian period is the strongest one and is also the major ore-forming period of Mo polymetallic ore deposits in East Qinling-Dabie Mountain region.

关 键 词：地球化学 辉钼矿Re-Os同位素测年 钼成矿作用 沙坪沟钼矿 东秦岭-大别山 

分 类 号：P618.65[天文地球—矿床学]