Geochemical constraints on a diversity of magmatic ore deposits associated with the Permian Emeishan Large Igneous Province, SW China

Abstract

Magmatic Fe-Ti-V oxide and Ni-Cu-(PGE) sulfide deposits are hosted in plutonic rocks of the Permian Emeishan Large Igneous Province, SW China. Spatially and temporally the plutonic rocks are associated with the Late Middle-Permian (-260 Ma) Emeishan flood basalts including high-Ti and low-Ti basalts and alkali rocks. These plutonic rocks are dated at -260 Ma, the same as the volcanic rocks. Both oxide-bearing and sulfidebearing rocks display distinctly different geochemistry, suggesting their derivation from various mantle sources and involvement of different degrees of crystal contamination. We propose that a mantle plume reached the base of South China at -260 Ma and generated various magmas at different depths in the mantle. The sulfide -bearing intrusions formed from high-Mg and low-Ti magmas from a lithospheric mantle, whereas the oxide-bearing intrusio~ls crystallized fiom highly differentiated, high-Fe-Ti-V mafic magmas that separated from more primitive magmas generated fiom an enriched, OIB-type mantle source. The spatially associated syenitic intrusions represent the residual liquid after the formation of the oxide-deposits and hosting rocks.