金川Cu、Ni(PGE)岩浆硫化物矿床成矿时代研究

金川Cu、Ni(PGE)岩浆硫化物矿床是世界最著名的矿床之一,其中超镁铁岩和矿床的形成时代一直备受关注,不同研究者采用不同的方法获得了大量的年龄数据,但均未获得公认一致的结果。文中通过对不同测试方法的适用性与局限性分析,结合金川岩体、矿体地质分异特点,对前人的和文中测得的同位素年龄数据进行分析研究,认为新元古代时期的成矿年龄(800 Ma左右)为后期构造变质叠加事件年龄,中元古代时期的成岩、成矿年龄(1 408~1 508 Ma)更接近实际的成岩、成矿事件年龄。这一成矿年龄的进一步厘定,说明了华北古陆边缘中元古代成岩成矿事件的重要性。

Metallogenetic epoch of Jinchuan Cu-Ni (PGE) magmatic sulfide deposit

The Jinchuan Cu-Ni (PGE) magmatic sulfide deposit is a super-large deposit famous in the world.In this article, we review the temporal evolution of metallogenesis of the Jinchuan deposit. Studies on the isotopic age of Jinchuan ore-bearing intrusion is on-going. Researchers have used various experimental methods to estimate the age of the mineralization, however, no reliable ages have been obtained.We suggest that this is mainly caused by the limitation of the experimental methods used and the complexity of geological processes. In this article, we analyze the applicability and limitation of various experimental methods, and examine the isotopic age combined with the diverse features of Jinchuan intrusion and ore body. We propose that the late Proterozoic ages are indicative of tectonic metamorphic events, and that the Mesoproterozoic is probably closer to the age of the metallogenetic events.