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湖南汝城高坳背钨—钼矿床是湘南地区近年发现的远景规模达大型或超大型的黑钨矿石英脉型热液钨—钼矿床,然而对该矿床与成矿有关的花岗岩的成岩年龄和钨—钼成矿年龄还缺乏研究。本文利用锆石SHRIMP U-Pb同位素定年方法对该矿区黑云母二长花岗岩进行了年龄测定,获得其侵位年龄为222.1±2.0Ma,其中还发现其锆石内核含古元古代—新太古代的继承锆石。晚三叠世年龄的锆石具低的εHf(t)值(-4.7～-10.9)和1.6～2.0Ga的Hf同位素两阶段模式年龄,表明它们的岩浆源区主要以华南古元古代基底物质或者更古老的基底物质改造而成。古元古代—新太古代继承锆石中正的εHf(t)值(4.3～8.5)的存在,暗示形成这些古老继承锆石的初始物质中有幔源物质的加入。利用辉钼矿Re-Os等时线法,获得该矿的成矿年龄为157.3±6.6Ma(n=5,MSWD=0.11)。高坳背钨—钼矿区黑云母二长花岗岩锆石年龄、Hf同位素资料和钨钼矿成矿年龄表明,花岗岩中存在古老地壳的残留锆石,说明花岗岩的物质来源可能与华南古老的陆壳基底有关,钨钼矿区黑云母二长花岗岩成岩时代为晚三叠世,而成矿时代为晚侏罗世,推测该矿深部有晚侏罗世的花岗岩存在。这些新的同位素年龄资料为研究华南同类矿床的形成演化与指导区域找矿提供了重要的地球化学依据。
The Gao Au Au Tungsten-Molybdenum Deposit in Rucheng, Hunan Province is a large-scale or super-large tungsten-molybdenite quartz vein type hydrothermal tungsten-molybdenum deposit discovered in recent years in southern Hunan Province. However, the granite age-related granitoid And tungsten - molybdenum mineralization age is still lack of research. In this paper, the dating of biotite monzogranite in this area was determined by SHRIMP dating of U-Pb zircons, and the emplacement age was 222.1 ± 2.0Ma, in which the zircon core was found to contain the Paleoproterozoic-Neo-Archean The inheritance of zircon. The late Triassic zircons have low εHf (t) values (-4.7 ~ -10.9) and Hf isotopes of 1.6 ~ 2.0Ga in two-stage model ages, indicating that their magmatic source areas are dominated by ancient Paleozoic basal material Or more ancient base material transformation made. The existence of εHf (t) values (4.3 ~ 8.5) in the Palaeozoic to Neo-Archean succession zircons implies the addition of mantle-derived materials to the initial materials that formed these ancient inherited zircons. The mineralization age of this deposit was 157.3 ± 6.6Ma (n = 5, MSWD = 0.11) by using the molybdenite Re-Os isochron method. Zircon ages, Hf isotopic data and tungsten-molybdenum mineralization age of biotite monzogranite in the Gao Au-Tungsten-Molybdenum Mine suggest that there are residual zircons in the ancient crust in the granites, indicating that the source of the granites may be related to the ancient continental crust in South China Basement. The biotite monzogranite in the tungsten-molybdenum mine is diagenetic in Late Triassic and the metallogenic epoch is Late Jurassic. It is presumed that there is Late Jurassic granite in the deep part of the mine. These new isotopic age data provide an important geochemical basis for the study of the formation and evolution of similar deposits in southern China and ore prospecting in the region.