GEOLOGICAL-GEOCHEMICAL FEATURES OF ORE-FORMING PROCESS AND ORIGIN OF DAZHUANGZI GOLD DEPOSIT,SHANDONG PROVINCE

Dazhuangzi gold deposit,occurred in Jingshan group metamorphic rocks on the margin of Jiaolai basin,is controlled by a low-angle slip fault zone—structural breccia marble zone,which provides structural and physical-chemical conditions for ore-forming processes.The isotopic geochemistry research indicates that the sulfur isotopic compositions of Dazhuangzi gold deposit are higher than those of other typical gold deposits of Jiaodong area.The δ³⁴S values of ore sulfur are generally greater than those of the old strata and granite in Mesozoic Era,reflecting that atmosphere water circulation results in fractionation of sulfur isotope.The scope of lead isotope of Dazhuangzi gold deposit is wide,suggesting that the lead belong to anomalous lead.The compositions of carbon and oxygen isotopes fall in values between that of magma carbonate and marble.According to the data of sulfur,lead,carbon and oxygen isotopes and fluid inclusions,it was indicated that the ore-forming matter is of multiple source.