Metallogenic processes and migration of ore-forming elements in the Wunugetushan porphyry Cu-Mo deposit, Inner Mongolia

Abstract: The Wunugetushan porphyry Cu-Mo deposit is one of the typical deposits in the Deerbugan metallogenic belt. Combining laboratory analysis with field observations, the authors quantified the migration of ore-forming elements by immobile plateau method and the formula given by Grant, and discussed the metallogenic processes. The results show that the percentages of SiO2, Al2O3, MgO, Fe2O3 gradual increased from the inner part to the outer part due to the continuous decrease of temperature, the migration of major elements led to the formation of some minerals whose zoning is consistent with the zoning of characteristic minerals such as quartz, feldspar, sericite and muscovite in Wunugetushan alteration zone. The magma originated from the mantle and was contaminated by crustal materials during the collision between Siberia plate and Mongolia plate. Cu, Mo were brought into the alteration zone, the percentage of the gaining (Xgp) of Cu and Mo was gradually reduced from the inner part to the outer part. Mo came from the surrounding rocks, whereas Cu was from parent rocks. In the course of alteration of plagioclase Mo precipitated and entered hydrothermal solution due to the complexation of CO32? , and then migrated. Pb and Zn were taken out of the inner zone and brought into the outer zone, and the elements were eventually concentrated in the outermost zone.