松潘-甘孜地块南缘燕山早期矽卡岩型钨钼矿床——来自大牛场成岩成矿年代学及锆石Hf同位素证据  

Early Yanshanian skarn W-Mo deposit in the southern margin of SongpanGanze terrane: Evidence from diagenetic and metallogenic chronology, zircon Hf isotopes in Daniuchang area

作　　者：谭洪旗[1,2,3] 朱志敏 周家云[1,2,3] 周雄 胡军亮[1,2,3,4] 刘应冬 TAN HongQi;ZHU ZhiMin;ZHOU JiaYun;ZHOU Xiong;HU JunLiang;LIU YingDong(Institute of Multipurpose Utilization of Mineral Resources,CAGS,Chengdu 610041,Sichuan,China;Technical Innovation Center of Rare Earth Resources,China Geological Survey,Chengdu 610041,Sichuan,China;Research Center of Multipurpose Utilization of Metal Mineral Resources of China Geological Survey,Chengdu 610041,Sichuan,China;College of Earth Sciences,Chengdu University of Technology,Chengdu 610059,Sichuan,China)

机构地区：[1]中国地质科学院矿产综合利用研究所,四川成都610041 [2]中国地质调查局稀土资源应用技术创新中心,四川成都610041 [3]中国地质调查局金属矿产资源综合利用技术研究中心,四川成都610041 [4]成都理工大学地球科学学院,四川成都610059

出　　处：《矿床地质》2022年第1期53-68,共16页Mineral Deposits

基　　金：国家自然科学基金项目(编号:41603034);中国地质调查局项目(编号:DD20190185、DD20221697)共同资助。

摘　　要：矽卡岩型矿床是钨、钼、锡等矿产的重要来源之一,中国的矽卡岩型矿床绝大多数分布于中国东部,成矿时代主要为燕山期。川西九龙大牛场是在松潘-甘孜地块新发现的矽卡岩型钨钼矿床,其成岩成矿时代尚未得到精确限定。大牛场地区铁厂河花岗岩体以二长花岗岩为主,少量正长花岗岩,而钨钼矿体主要产于矽卡岩中。文章对该矿床开展锆石U-Pb定年、Hf同位素和辉钼矿Re-Os定年,结果显示铁厂河花岗岩中锆石LA-ICP-MS UPb年龄为(166.0±0.9)Ma(MSWD=0.27),与矿石中辉钼矿Re-Os加权平均年龄((166.8±1.7)Ma,MSWD=0.90)在误差范围内基本一致,成岩成矿时代是燕山早期;锆石ε_(Hf)(t)为-10.69~4.37(平均0.82),模式年龄T_(DM2)为1229~931Ma(平均1099 Ma)和1884 Ma,表明该花岗岩为扬子地块基底古元古代与中元古代地壳重熔形成的。结合前人在该区获得的成岩成矿年龄,反映研究区内166 Ma左右存在一期与花岗岩浆有关的钨钼成岩成矿事件,这一发现为川西九龙地区及其周缘矿产勘探拓宽了思路。Skarn deposits are an important source of W, Mo, Sn, and other minerals. Most of the skarn deposits in China are distributed in eastern China, and the metallogenic epoch is mainly Yanshanian. The Daniuchang W-Mo deposit, located in the Jiulong region of the western Sichuan Province, is a newly discovered skarn deposit in the Songpan-Ganze terrane, and its genesis is rarely studied. The Tiechanghe granitoids in Daniuchang area are mainly monzogranite with a small amount of syenogranite, while the tungsten and molybdenum ore bodies mainly occur in skarn. In this paper, zircon U-Pb dating, Hf isotope and molybdenite Re-Os dating are carried out for the samples from the deposit. The result shows that the zircon LA-ICP-MS U-Pb age for Tiechanghe granite is(166.0±0.9) Ma(MSWD=0.27), which is basically consistent with the molybdenite Re-Os weighted average age for ores((166.8±1.7)Ma, MSWD=0.90), The age of intrusion/mineralization is Early Yanshanian.The zircon ε_(Hf)(t) ranges from-10.69 to 4.37(average 0.84), and the model ages range from 1229 Ma to 931 Ma(average 1099 Ma) and 1884 Ma, suggesting that the granite may have been formed by the remelting of the Paleoproterozoic and Mesoproterozoic crust in the basement of the Yangtze Block. Combined with the intrusion and mineralization ages published previously, there should be an important magmatic and metallogenic event of around 166 Ma forming the granitic intrusions and related W-Mo deposits in the study area. The data is helpful for mineral exploration in the Jiulong region and its surrounding areas in western Sichuan Province.

关 键 词：地球化学 辉钼矿Re-Os 锆石U-PB 花岗岩 松潘-甘孜 川西 

分 类 号：P618.65[天文地球—矿床学] P618.67[天文地球—地质学]