云南麻花坪钨铍矿成矿年龄及流体包裹体特征

The Ore-Forming Age and Fluid Inclusion Characteristics of the Mahuaping Tungsten-Beryllium Deposit in Yunnan Province

为探讨云南麻花坪钨铍矿床成因及其成矿动力学意义,对该矿床开展了白云母40Ar-39Ar定年及流体包裹体研究。结果表明,矿床成矿年龄为(32.06±0.11)Ma,成矿流体为富CO2和高F的低盐度流体。研究认为,麻花坪钨铍矿床为花岗质岩浆热液演化晚阶段形成的热液脉型矿床,是印度-亚洲大陆碰撞在三江构造带的成矿作用响应,成矿可能与地壳深熔花岗质岩浆活动有关,反映了32 Ma左右金沙江构造带强烈的挤压、走滑、逆冲推覆环境,揭示在与地壳深熔花岗质岩浆活动有关的热液作用具有稀有多金属矿产的找矿前景。

In order to explore genesis of the Mahuaping tungsten-beryllium-fluorite deposit in Yunnan Province and to reveal its metallogenetic dynamic significance, the muscovite 40Ar-39Ar dating and fluid inclusion study of the deposit have been carried out in this paper. The results show that the ore-forming age of the deposit is(32.06±0.11)Ma, and the ore-forming fluid is characterized with low salinity, rich CO2 and high F content. It is believed that the Mahuaping tungsten-beryllium-fluorite deposit is a hydrothermal vein type deposit formed in the late stage of granitic magmatic hydrothermal evolution, and is the metallogenic response of the Indian-Asian continental collision in the Sanjiang tectonic belt. Its metallogenesis could be related to the deep-melting granitic magmatism in the crust. It could be formed in the strongly compressional, strike-slip and thrust nappe environments of the Jinshajiang tectonic belt around 32 Ma. It is revealed that the hydrothermal process associated with the anatectic granitic magmatism in the crust could produce the prospective target for polymetallic rare mineral resources.