| The middle and lower Yangtze River valley and adjacent region of China arethe most important metallogenic belt of gold(copper)-bearing skarn deposits.Study on the two main gold-bearing skarn deposits and contrast with othersgold-bearing skarn deposits in the studied areas, suggest that their favorabletectonic settings are depression of platform margins as well as areas near deepfaults within the platform. The auriferous skarns occurring in the mobileplatform may be calcic or magnesian, and belong to the oxidized type, but theAu-bearing skarns occurring in the island-arc setting belong to reduced type.The related intrusives are mainly hypobyssal calc-alkaline intermediate-acidrocks. Most of them are of Yanshanian(180～107Ma), and mainly came from uppermantle and might be contaminated by salic crustal components. Study of skarnminerology suggests that the compositions of coexisting pyroxenes and garnetsare diopside and andradite, indicating the higher oxygen fugacity and loweracidity conditions. In the ores, gold is often intimately associated witharsenides, bismuthides, tellurides and selenides, Magnesioferrite wasdiscovered for the first time in China from Sanpu of Anhui Province. Therefore,Au, Cu, Ag, Bi, Te, Co(Se), Pb, Zn are important geochemical ore-searching indicators.The comprehensive mineralized zonal model from intrusive to carbonate wallrocks is:Cu(Mo)→Cu (Fe)→Cu (Au)→Au→Au (Pb,Zn,Ag). Study of mineralparagenesis and fluid inclusions suggest that the gold minerals were precipitatedin the postskarn retrograde metasomatic stage in the temperature 350～126℃,with salinities 18.6～3.1wt%NaCl. Skarn were formed in the temperature 680～400℃with salinities 59.7～31.3wt%NaCl. The magmatic magnesian skarn wasdiscovered in the Tian Mashan gold deposit, Tongling, Anhui of China.The regional geological and geochemical evaluation criteria andminerogenetic series of gold-bearing skarn deposits in the studied area have beensummarized.
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