Gold deposits hosted in the Gezhen shear zone at Qingxi, Hainan Island occur in the Precambrian metamorphic rock series and are regionally developed in the N-E direction along the tectonic zone. From northeast to southwest are distributed the Tuwaishan-Baoban gold mining district, the Erjia gold mining district and the Bumo gold mining district, making up the most industrially important gold metallogenesis zone on the Hainan Island. Isotope geochemical studies of the typical gold deposits in this metallogenesis zone indicate that their ore-forming materials stemmed largely from the Baoban Group migmatite series, though the involvement of some plutonic materials could not be ruled out. The ore fluids are the mixture of migmatitized hydrothermal solutions and meteoric waters in addition to the involvement of local magmatic hydrothermal solutions. The superimposition of plutonic materials and magmatic hydrothermal solutions is controlled by the deformation environment of the shear zone and later magmatic activities. Obvious variations are noticed in isotopic composition in the region studied, probably related to tectonic deformation, metamorphism and other evolutionary characteristics. This study is of great significance in understanding the relationship between the shear zone and gold metallogenesis, the rules of gold metallogenesis and gold ore prognosis.
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