Geochemistry And Deep Ore Prediction Of The Jiaojia Gold Deposit, Shandong

East Shandong (Jiaodong) is known as a concentrated district for gold resources and the Jiaojia is the biggest gold mine in China. As a typical altered fracture zone type (also referred as "Jiaojia type") gold deposit, the Jiaojia mine is located in the western active margin of the circum-Pacific metallogenic province, where Archean to Proterozoic granites and greenstones are well developed and multi-cycle events of tectonic movement, metamorphism, magmatism and mineralization happened.The tectonomagmatic evolution and its relationship to mineralization in East Shandong have been long debated. Much controversy has been provoked about the genesis of the Linglong and Guojialing granites, their relations to gold deposits, and the timing of gold mineralization. Based on complicated geological, geochemical and geophysical investigations, this dissertation summarized the tectonomagmatic evolution and mineralization of the study area and put forward a geochemical prospecting model for the Jiaojia deposit. It is then predicted that another gold enrichment zone should exist in deep sites of the deposit and that such a law may be applied to the whole Jiaojia gold mine.The Linglong granites are distributed along regional inverse-dipping NE-SW striking tectonic lineaments. On major and trace elements discrimination diagrams for petrogenetic-tectonic settings, the granites plot in orogenic or syn-orogenic field and exhibit characteristics of S-type granites. A large body of isotopic data changes from 102Ma-1718Ma, and concentrates in early Middle and late time-intervals. The late interval is from 110 Ma to 160 Ma. And this fact supports the opinion that the Lionglong core complex formed during the Yanshan epoch. Rb-Sr isotopic dating on fluid inclusions in Au-bearing quartz veins gives an age of 124±1 Ma. Lead isotopes and REE geochemistry indicate that the ore-forming materials were derived from pre-Cambrian metamorphosed basement and the Linglong granites. And all the above supports that the metallogenesis is directly related to the formation of Linglong core complex.From genissic granite inward to the major fault plane, the altered fault zone in the Jiaojia deposit varies from ductile deformation, through ductile-brittle deformation, to brittle deformation with decreasing thickness of the sub-zones. The inner sub-zones formed relatively later and seem to occur at a shallower depth than the outer...