矿床地球化学国家重点实验室知识库

Generation of the Late Permian Emeishan large igneous province has recently been attributed to the ascent of a mantle plume head. The Hongge layered intrusion, hosting a giant Fe-Ti-V deposit and Ni-Cu-PGE mineralization, is contemporaneous and chemically correlated with high-Ti type Emeishan flood basalts in the Pan-Xi area, southwestern China. Basalts within the lower part of the lava sequence (HT3) were strongly contaminated by material mainly from the middle to upper crust, whereas overlying basalts (HT2) were contaminated by a gabbroic layer near the crust-mantle boundary. In contrast, the magma parental to the Hongge intrusion assimilated appreciable amounts of a plagioclase-rich lower-crustal end-member. The Hongge intrusion may have acted as an opensystem conduit through which the lavas erupted. Equilibration of Fe-Ti oxides and immiscible sulfide liquids with successive batches of magma produced the giant Fe-Ti-V deposit, and a gradual increase in the Ni, Cu, and PGE contents of later differentiates.