The Tuwaishan,Baoban,Erjia,Bumo and other gold deposits in western Hainan occur in Precambrian metamorphic clastic rocks and are structurally controlled by the Gezhen shear zone.Fluid inclusion strdies have been carried out of the gold deposits mentioned above .The homogenization temperatures of the whole fluid inclu-sion population range from 140℃ to 370℃,indicating that gold was precipitated mainly at 240-250℃.The salinities are within the range of 2.0-9.2wt% NaCl equiv.and the pressure of formation of the deposits was estimated at about 270×0^5-500×10^5Pa ,corre-sponding to a depth of about 1.0-2.0 km under lithostatic confinement.Chemical strdies show that the ore fluid is of the Na^+(K^+)-Ca^2+-Cl^-(F^-)type.The δ^18O and δD values of the fluid vary from-2.7%0-+4.4%0 and -50%0-87%0.Evidence developed from fluid inclusions and geological setting indicates that the ore fluid was a mixture of mag-matic and meteoric-hydrothermal waters.Changes in chemical composition and δ^18O and δD of fluid inclusions from one ore field to another seem to be related with regional tectonism, metamorphism and magmatism.
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