Abstract:

The Bairendaba and Weilasituo Ag-Pb-Zn deposits are two large-size deposits in the same orefield, with the prospective reserves of Ag being over 10 000 tons and Pb and Zn about 600 million tons. The magmatism of these two ore deposits was controlled by mantle branch in southern Da Hinggan Mountains. Since Mesozoic, intensive magmatism has generated the channel for the upwelling of deep source materials and resulted in the formation of a series of fracture systems related to igneous activities, which served as important ore-controlling structures for the  migration and concentration of hydrothermal fluids. Studies demonstrate that different scales of structures dominate the mineralization distribution of this ore deposit. The orefield is controlled by the northeast principal detachment zone on the south margin of the mantle branch in southern Da Hinggan Mountains, the deposits are controlled by a series of secondary detachment belts, and the ore bodies are controlled by tensile or tensile-shearing faults. Geochemical studies indicate that ore-forming materials were mainly derived from the depth, with the participation of some crustal materials during the upwelling of hydrothermal fluids.

Key words: mantle plume, mantle branch, mineralization model, Bairendaba, Weilasituo, Inner Mongolia