Geological Characteristics And Genesis Of Danizhuang Copper Depoist In Luzong Basin

Danizhuang copper depoist is a small scale of porphyry depoist,discovered from Luzong basin in recent years.In this paper,we have characterized wall rock alteration of Danizhuang copper depoist, on the basis of detailed field observations and petrographic and mineralogical studies,including potassic alteration, sericitization, silicification,propylitization, clayization,carbonatization;and have concluded the characteristics of mineralization, the sequence of mineral deposition and the ore-forming stages,which is potassium silicate stage,quartz sulfide stage,carbonate stage. The quartz sulfide stage can be further divided into quartz sulfide sub-stage and epidote-chlorite sub-stage.We have collected magmatic rocks(orthophyre) related to ore forming and yield the age of 126.6±1.8Ma by LA-ICP-MS zircon U-Pb dating, belonged to Early Cretaceous, related to the intrusive activity of Shuangmiao Formation.Studying on main and trace elements of whole intrusive rocks show that:magmatic rocks related to ore forming is orthophyre forming in the late stage magmatism in Luzong basin.The source of magma might be metasomatic mantle closing to the enriched mantle I,and the evolution of the magma was influenced by the crust contamination.The tectonic setting of formation of The magmatic rocks and deposits existed a change from volcanic-arc environment to within plate environment, corresponding to the transition of compressional to extensional regime,we have discussed the source, evolution, tectonic setting of magma,and divided diagenesis in a sequence,among the Danizhuang intrusive rock, late stage of Bajiatan magmatic rocks,and other orthophyre forming in the late stage magmatism in Luzong basin,based on making geochemical diagrams. Geochemical data show:the Danizhuang intrusive rock and late stage of Bajiatan magmatic rocks might be a result came from the same magma.Based on compared with similar depoist in other volcanic basin of eastern china,We have dicussed ore-control factors and regular to forming this type of depoist,have established basically a deposit metallogenic model and have showed the prospecting to find porphyry copper deposit in this area.