Discussion On Geological Characteristics And Genesis Of Zhanggongling Gold-silver Polymetallic Deposit In Guangxi Province

The Zhanggongling gold silver polymetallic deposit is located in the northeast edge of Dayaoshan metallogenic belt in South China.Frequent tectonic activities and strong magmatic activities provide abundant fluids,materials and heat sources for the area.On the basis of previous studies,according to the field geological deposit investigation,combined with the application analysis of rock geochemical characteristics,fluid inclusion temperature measurement technology,the genesis of Zhanggongling gold silver polymetallic deposit is systematically studied.The main conclusions are as follows:(1)Zhanggongling deposit is a polymetallic deposit,which is mainly composed of silver and associated with Au,Pb,Zn,the deposit is hosted in Daning pluton,controlled by NWW trending fracture zone.The ore body is vein like.The gold ore is dominated by argentite and pyrite.According to the structure and structure of the ore,the paragenetic Association of minerals and the interpenetrating relationship between veins,the mineralization process is divided into three main stages.(2)The lithology of the area is mainly granodiorite,monzonitic granite,aplite and quartz porphyry.Most of them belong to high-k calc alkaline shoshonite series and peraluminous I-type granite with high differentiation and high degree of evolution;The Daning pluton is rich in Th,U,K,Pb,Zr and Hf,but depleted in Ba,Nb,Sr,P and Ti;The REE distribution curve is relatively right inclined,enriched in LREE and gently in HREE,and the negative Eu anomaly is not obvious.The average heat production rate of Daning granite is 5.4?Wm^-3,which is a high-yield granite.Chudong pluton is a ore bearing porphyry,both of which have certain metallogenic potential.Daning and Chudong rocks have certain metallogenic potential.(3)The ore-forming fluid belongs to the NaCl-H₂O system.The average temperature and salinity of the main ore-forming period are 228.7?and 16.8%.The ore-forming fluid is mainly rock slurry water mixed with a small amount of metamorphic water and meteoric water.The calculated metallogenic depth ranges from 1.06 km to 2.69 km.The Zhanggongling deposit belongs to the magmatic hydrothermal deposit controlled by the fracture zone,Daning HHP granite may be the main source of metal source and heat source in the deposit.