Lead isotopes have been widely applied in geochemical explora tion and evaluation of ore deposits, as well as in ascertaining the age of miner alization and the source of ore fluids. Long-term practice showed that the meth od of lead isotope targeting is somewhat efficient for macroscopic evaluation of forecasting areas, but not powerful enough for forecasting concealed orebodies. As the contents of U and the variation of U/Pb ratio sharply decrease with dept h in the lithosphere, U-Th-Pb isotopic differentiation must have occurred duri ng the crust-mantle evolution. Lead isotopic ratios show a wide variation range , varying in the front of mineralization and shallow-derived ores, but maintain ing very stable in the major orebody and being usually close to the average isot opic composition of the crust and mantle of the continent block from which the o res were derived. Therefore, the lead isotopic composition can serve as a measur e for identifying the position of mineralization. The lead isotope geochemistry was applied to the exploration and evaluation of the Baoban gold deposits of Hai nan Province, China. The analytical results of ore veins and adjacent rocks show ed that there is a correlation between the lead isotope data and the position of orebody. Based on the experience from the Baoban gold deposits and other ore de posits in Yunnan Province, an exploration principle has been established, that i s, positive anomalies of lead isotope eigenvectors for prospecting deep-seated orebodies and negative anomalies of eigenvectors for enlarging lateral explorati on surrounding the known deposit. The ore beds in the Erjia and Beiniu mining di stricts should be assigned to the deep part of the orebody and those in the Tuwa ishan mining district should be the shallow part, so ore beds corresponding to t hose in the Erjia and Beiniu mining districts may be found in the Tuwaishan mini ng district.
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