二叠纪峨眉山地幔柱岩浆成矿作用的多样性

Metallogenic Diversity Related to the Late Middle Permian Emeishan Large Igneous Province

二叠纪峨眉山地幔柱形成了规模巨大的大火成岩省、并伴随众多具有经济价值的矿床。地幔柱岩浆分别形成了高钛和低钛2个主要玄武质岩浆系列,并显示了一定的成矿专属性,赋存铜镍硫化物矿床的小型镁铁-超镁铁质岩体原始岩浆的成分类似区内低钛苦橄岩,而赋存钒钛磁铁矿矿床的层状岩体,其原始岩浆成分特征与高钛苦橄岩类似。不同含矿岩体的岩石学、地球化学和含矿性各有差异,这主要取决于岩浆源区特征、岩浆演化过程、地壳混染和岩浆侵位过程。本文对峨眉山地幔柱岩浆成矿作用近年来在上述几方面的研究进展进行了综合和评述,指出地幔柱成矿作用研究存在的一些值得研究的问题。

The Permian Emeishan mantle plume is responsible for the generation of a large igneous province and associated economically important mineral deposits. Plume-derived basaltic magmas can be divided into two series in term of geochemical compositions,i.e.,high-Ti and low-Ti series. Each of the series is genetically linked to distinct types of mineral deposits. Ni-Cu-（ PGE） sulfide deposits are hosted in small mafic-ultramafic intrusions which are supposed to be derived from low-Ti picritic magma due to high degrees of partial melting of shallower mantle source,whereas Fe-Ti oxide deposits hosted in layered intrusions are supposed to be derived from high-Ti picritic magmas due to low degrees of partial melting of deep mantle source. The diversity in different ore-bearing intrusions is related to several key controlling factors,such as magma source,fractionation process of magma,crustal contamination and transportation and emplacement of magma. The review is given for the recent progress on the key issues of plume-related mineralization and outstanding issues worth for future research.