Abstract: Northwestern Hubei Province, on the north side of the Qingfeng fault, is an important part of the Qinling metallogenic belt. It includes Wudangshan and its northwestern neighboring regions. Home to the Yindonggou, Xujiapo, Shejiayuan and Liudou large to medium-sized Ag-Au deposits, the area is famous for producing Ag, Au, Pb and Zn polymetallic minerals. It can be divided into the north and south belts according to the distribution characteristics and controlling factors of ore deposit. The north belt on the north side of the Qinggeng-Baoxi fault contains the Santianmen Au-Sb and Liudou Au deposits and many gold spots, distributed along both sides of the Yunxian-Yunxi fault. It mainly produces Au and Sb hosted in wall rocks of the overlying Doushantuo Formation and Palaeozoic strata. The south belt contains the Yindonggou large Ag-Au and Xujiapo medium Au-Ag deposits concentrated in the underlying Wudangshan Group. All deposits are controlled by toughness and NW-trending ductile brittle shear zone, with orebodies occurring in branch of brittle-fracture and fracture. Carbon, H and O isotopic compositions indicate the ore-forming fluids of Ag-Au and Au deposits are primarily metamorphic hydrothermal fluids that later mixed with meteoric water; while Au-Sb deposits accumulate towards the meteoric water line, indicating meteoric water may be dominant in the ore-forming fluids of Au-Sb deposit. Sulfur isotopic profile shows regional activity of ore-forming fluid and characteristics of strata-bound sulfur source. According to the enrichment characteristics of ore-forming elements, Cu, Pb, Zn, Au and Ag are enriched in the underlying Wudangshan Group, while Ag-Au/Au-Ag/Au and Au-Sb ore deposits occur in the overlying Doushantuo and Dengying Formations and Palaeozoic strata, respectively. In the western part of the study area, a large number of Au-Sb and Hg-Sb deposits are distributed in the Devonian strata of Shaanxi, suggesting a crustal continuum model for orogenic-type deposit. Clearly, under structural control, ore formation is closely related to the relatively high elemental abundance in the strata. Considering ore geology, ore-forming fluids and ore-forming age, we believe the northwestern Hubei Province Ag-Au and polymetallic deposits are orogenic type deposits, formed in accretionary orogens produced by the northward oceanic plate subduction along the Mian-Lüe Suture during the Triassic.

Key words: Ag-Au and polymetallic deposits, orogenic-type deposit, ore-forming, northwestern Hubei Province