Jiaodong Granitoids and Gold Mineralization

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Jiaodong Granitoids and Gold Mineralization

Gold Production in Jiaodong started in 598 AD, reached 89.5% of the country's total output in 1078 AD ac is now still on the topmost in China. The Jiaodong Group forming the Neoarchaean crystalline basement belongs to the magnetite tyep consisting in the main of gold-bearing basic to intermediate-acidic matavolcanics. The Mesozoic granitoids generated from partial remelting of the Jiaodong Group consequently belong also to the I-type and magnetite series by showing strong petrochemical, mineralogical and crystallochemical inheritance to the Jiaodong Group .There are three major types of granitoids hosting gold deposits in Jiaodong, namely the Lingong monzonitic grenite (J2 ), the Guojialing granodiorite (J3 )and the Kunyushan monzonitic granite (K1). the isotopic chronological data indicate that there are also three stages of gold mineralization (K1 )corresponding to the formation of the three major types of gramitoids, but the former is not the direct Product of magmatic differentiation from the latter .The Mesozic tectonism and dynamometamorphism on mobile margin of continental Plate Played an important role in both deliverance of gold from source rocks into hydrothermal solution and later deposition from the hydrothermal solution to form gold deposits. Mineraloglcal criteria of redox conditions of granitoids, mineraloglcal, petrochemical and crystallochemical data favorable for gold mineralization in general, and especially in Jiaodong granitoids, are summarized. Difference in gold mineralization in the three major types of Jiaodong grauitoids is also roughly given.