粤北梅子窝钨矿区隐伏花岗闪长岩锆石SHRIMP U-Pb年龄与~(40)Ar/~(39)Ar成矿年龄及其地质意义

梅子窝钨矿位于粤北瑶岭—梅子窝钨矿带的东部,成矿作用同期形成白云母的40Ar/39Ar年龄为(155.9±0.6)Ma,与华南中生代燕山期大规模W,Sn成矿作用的年龄一致,代表梅子窝钨矿的成矿年龄。矿床下部600m中段附近出现的隐伏黑云母花岗闪长岩体的锆石SHRIMPU-Pb年龄为(430.4±3.6)Ma,为加里东期,与成矿作用无关。因此,矿区不存在前人提出的两套叠加的"五层楼"成矿模式。成矿年龄与隐伏花岗闪长岩的年龄显示梅子窝钨矿的形成可能与更深部的隐伏燕山期花岗岩有关,矿床向深部可能延伸更大。

Zircon SHRIMP U-Pb Dating of the Buried Granodiorite and Muscovite 40Ar/39Ar Dating of Mineralization and Geological Implications of Meiziwo Tungsten Deposit, Northern Guangdong Province, China

The Meiziwo tungsten deposit is located in eastern part of Yaoling-Meiziwo tungsten mineralization zone, northern Guangdong province. The ⁴⁰Ar/³⁹Ar age of muscovite formed in syn-mineralization period is (155.9±0.6) Ma, consistent with large scale tungsten and tin mineralization in the Mesozoic Yanshanian period in South China. This date represents the mineralization age of the Meiziwo tungsten deposit. The zircon SHRIMP U-Pb age of biotite granodiorite body, occurring at about 600 m level in the lower part of the mine, is (430.4±3.6) Ma. This age suggests that the granodiorite body formed in the Caledonian period has no genetic relation to the tungsten mineralization. Our new data disagree with the previously proposed model for the tungsten mineralization, i.e., two times of “five-story”mineralization overprinted each other in this deposit. The ages of the mineralization and granodiorite indicate that the formation of Meiziwo tungsten deposit may be related to an Yanshanian granite buried in a deeper level, and therefore, we expect that the ore bodies might have a larger extension in depth.