Fluid Inclusion Study Of The Oubulage Copper(Gold)Deposit In The Wulate Houqi,Inner Mongolia Autonomous Region

The Oubulage porphyry copper(gold)deposit lies in the western segment of the Langshan District,which was discovered by the No.511 team Nonferrous Bureau of Geological Prospecting Geological of Inner MongoliaThrough geological observations,rock-mineral determination,homogenization method of fluid inclusion,and combing previous research methods,the paper systematically summarizes the geological characteristics and the nature of the fluid inclusions of the Oubulage porphyry copper(gold)deposit.Summarized as follows:(1)The outcropped strata in study area are mainly Upper Carboniferous strata and Lower Permian volcanic complexes.Ore bodies mainly occur in quartz porphyry and its contact zone,present as irregular short lenticular,disseminated,lumpy and veins.(2)Structures of ores include disseminated,fine vein and vein,the textures include shape of granular texture,hypidiomorphic-automorphic granular texture,metasomatic texture,metasomatic relict texture and exsolution texture.Ore minerals are mainly chalcopyrite,pyrite,pyrrhotite,arsenopyrite,secondary minerals include sphalerite,marcasite,galena,tetrahedrite etc.The alteration of Oubulage porphyry copper(gold)deposit's surrounding rock is intensively,mainly include silicification,sericitization,kaolinization,propylitization and carbonatization.Silicification and propylitization are closely related to mineralization.Depending on the mineral fabric and mineral assemblage,the metallogenic process can be divided into three stages:early stage mineral assemblage of arsenopyrite+quartz+pyrite,in stage:mineral assemblage of chalcopyrite+metal sulfide+quartz,late stage:mineral assemblage of calcite+quartz±pyrite(3)Pb isotope studies suggest that it is normal lead,from the tectonic distribution model and its ??-?? genetic classification diagram,the writer infers that Pb of the Oubulage porphyry copper(gold)deposit belong to the upper crust,the formation of ore deposit may be associated with hydrothermal water.(4)There are mainly two types of fluid inclusions in this deposit,gas-liquid phase and liquid phase.Fluid inclusion to study shows:The homogenization temperature varies between 151.5-405.7?,mainly concentrated in the 190-350?,reflecting the medium-low temperature ore-forming fluid.Ore fluid salinity distribute between 2.24-15.17%,mainly concentrated in the 6-11.0 wt%belong to medium-low salinity fluid.Density change in the 0.67-0.957g/cm3,mainly concentrated in the 0.75-0.95g/cm3,ore-forming fluid is low density fluid.Metallogenic pressure range from 4.47-293.69MPa,concentrated in 4.47-120Mpa,metallogenic depth is estimated through metallogenic pressure,ranging from 0.47 to 3.84km,concentrated in 5.158-13.478km.Density increases gradually with the decrease of temperature and pressure,showing negative correlation.Above all,the Oubulage porphyry copper(gold)deposit is hydrothermal deposit having characteristics of medium-low temperature,medium-low salinity and low density.