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

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、...

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

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.