安徽沙坪沟斑岩钼矿锆石U-Pb和辉钼矿Re-Os年龄  

Zircon U-Pb Dating of Ore-Bearing Rocks and Molybdenite Re-Os Age in Shapinggou Porphyry Molybdenum deposit,Anhui Province

作　　者：孟祥金[1] 徐文艺[1] 吕庆田[1] 屈文俊[2] 李先初 史东方 文春华[4] 

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和资源评价重点实验室,北京100037 [2]中国地质科学院国家测试分析中心,北京100037 [3]安徽地勘局313地质队,安徽六安237010 [4]中国科学院贵阳地球化学研究所,贵阳550002

出　　处：《地质学报》2012年第3期486-494,共9页Acta Geologica Sinica

基　　金：国家自然科学基金重点基金项目(编号40930418);深部矿产资源立体探测技术及实验研究项目(编号SinoProbe-03-04);国土资源部专项研究计划(编号20010103);国家地质调查专项(编号1212010012010)共同资助的成果

摘　　要：沙坪沟斑岩钼矿是大别成矿带近年发现的超大型矿床。在对矿化特征分析的基础上,对其进行了成岩成矿年代学研究。采用LA-ICP-MS锆石U-Pb测年技术,得到含矿岩体的成岩年龄。细粒石英正长岩与中粒石英正长岩分别形成于122.51±0.81Ma和121.5±1.3Ma,正长斑岩形成于120.7±1.1Ma。通过矿床辉钼矿Re-Os同位素分析,获得其模式年龄为100±1.8～113.6±1.7Ma。成岩与成矿时差约7Ma,指示含矿热液活动时限较长。长时间的热液活动可能是形成沙坪沟超大型斑岩钼矿床的重要因素。沙坪沟钼成矿时间与大别带钼矿化时间(133～110Ma)高度一致,与东秦岭晚期钼矿化时间相同。大别带钼矿是秦岭-大别成矿带的组成部分,形成于相同构造背景下,是区域构造岩浆作用的产物。The Shapinggou deposit occurred in the Dabie metallogenic belt is a superlarge porphyry molybdenum deposit discovered in recent years.Based on the analysis for the mineralization feature of the deposit,zircon LA-ICP-MS U-Pb ages were determined for the ore-bearing rocks in Shapingguo deposit.Zircon U-Pb dating yields ages of（122.51±0.81）Ma,（121.5±1.3）Ma and（120.7±1.1）Ma for fine-grained quartz syenite,medium-grained quartz syenite and syenite porphyry,respectively.The187Re and187Os contents of molybdenite from the molybdenum deposit are determined by the Inductively Coupled Plasma Mass Spectrometry（ICP-MS）.The Re-Os model ages of the molybdenite samples vary from（100±1.8）Ma to（113.6±1.7） Ma.The time difference between magmatism and mineralization of the Shapingguo deposit was about 7 Ma,which implicated there long active history of the ore fluid in the deposit.The long activities of the ore fluid in the deposit may be a key condition of being a superlarge molybdenum deposit.The ore-forming age of the Shapingguo deposit is identical to the age of porphyry molybdenum mineralization in the Dabie metallogenic belt,which in the later molybdenum mineralization period in the East Qinglin Mountains.The molybdenum deposits occurred in Dabie Mountains are a main part of the East Qinglin-Dabie metallogenic belt.The porphyry molybdenum deposits in the East Qinglin belt and in the Dabie belt are products of syntectonic-magmatic activity,which shared similar settings of metallogenic dynamics.

关 键 词：锆石U-PB年龄 辉钼矿RE-OS年龄 斑岩钼矿 沙坪沟 大别成矿带 

分 类 号：P618.65[天文地球—矿床学] P597.3[天文地球—地质学]