The Porphyric Intrusion Of Xixia,Henan,Pipagou Gold Deposit And Related Mineralization

The Pipagou gold deposit is located in southwestern of Xixia county,Nan yang,Henan province.It is located in extrusion collision zone between the North China craton and the Yangtze craton.It is a typical magmatic breccia deposit.The Jingziguan-Xichuan-Neixiang fault plays a major role in the mineralization of the Putang mining area.Proterozoic Douling group is the main ore-bearing strata,which is dominated by biotite plagioclase gneiss.Gold orebodies are obviously controlled by breccia bodies.The gold mineralization is mainly hosted in the matrix of granite porphyry breccia,pyrite is the dominated and also the major gold-bearing sulfide in ores.By studies on the features of geology,geochemistry,sulfur isotopes composition,hydrogen and oxygen isotopic composition and fluid inclusions,this paper achieve a few understanding as follow:The granite porphyry of the deposit is peraluminous,calc-alkaline and high-K calc-alkaline series.Trace elements studies show that granite porphyry is enriched in Rb,U,K,Sr and other LILE,depleted in Nb,Ta,P,Ti and other HFSE.The total contents of rare earth elements in the rock are higher than that in the pyrite,showing LREE enrichment with a slight Eu negative anomaly.The REE Chondrite-normalized pattern of the ore and the rock are LREE-enriched,and homology.It is infer that metallogenic materials from the magma in depth.Fluid inclusions are mostly liquid-rich aqueous inclusions.The homogenization temperatures of fluid inclusion is 270-350?,and the temperature of the mineralization is mainly concentrated in the range of 260-320?.The salinity of the ore-forming fluid is 4.3-7.6 wt%NaCl,with averagely 6.22 wt%NaCl,and the ore-forming fluid is high temperature and low salinity fluid.Metallogenic pressure is 5.2-12.6MPa,and the depth of mineralization is between 0.6-1.3 km.H-O isotope of quartz shows that ore-forming fluid is mixed solutions of magmatic hydrothmal and meteoric water,in which meteoric water is the main component.Sulfur isotopic composition of the deposit is close to meteorite sulfur,indicating that the sulfur of the deposit is from granitic magma in deep environment.Gold Deposit belongs to gas-liquid hidden exploding breccia gold deposits.The deposit is formed by a series of filling mineralization after hydrothermal metasomatism and gas-liquid cryptoexplosion.