| Shabao-Wawuo(copper)iron polymetallic deposit in Pulandian City of Liaoning Province is located in the Chengzitan fault block in Sino-Korean quasi-platform,Jiao-Liao platform uprise and west of Fuzhou platform subside;Jinzhou deep major fracture and Pikou-Mopan-Gunmalin polymetallic metallogenic belt,which is characterized by a skarn type deposit.Geotectonic location of the deposit is in the northeast of the North China craton,east of Tan-Lu fault zone.Based on grounded field work,this papers integrated the following sugject Geology,ore deposit geology,petrology,petrogeochemistry,isotope geochemistry,fluid inclusion body,various subject of scientific theory and method,on geological features and metallogenic origin of the deposit,a series of research can be made as follows:The deposit is mainly controlled by the contact zone between the magmatic rock and the strata,and the skarn belt formed by the contact between the biotite granodiorite porphyry and the shaly limestone is the main part of the orebodies,and the orebodies are occurred in vein or lens The orebodies are almost free from interlayer,and their occurrences are alomost consistent with surrounding rock,the mineral composition in thedeposit shows low temperature characteristics,so the deposit is skarn-type deposit,of great significance in deep prospecting.Mine area have found three(copper)iron ore(mineralized)body,of which the second mineralized body show good mineralization effects and shall be the focus of this study.The main types of iron mineral in the iron ore are magnetite?hematite? limonite?pyrite?chalcopyrite and so on.Mineral textures mainly include fractured texture ?euhedral to semi-euhedral granular texture,metasomatic texture.Mineral structures mainly include block?veinlets and disseminated structure,and so on.Gangue minerals are mainly garnet?tremolite?epidote?calcite?quartz.The wall-rock alteration is strong,and can be divided into three main categories ?skarnization?silicification,carbonation.On the basis of observed mineral assemblages,the formation stage of the deposit can be divided into three mineralization stage of skarn,quartz sulfide and epoxide stage,in which the skarn mineralization stage is the main mineralization stage early skarn stage(pure skarn stage)?late skarn stage(magnetite stage)oxide stage,the late skarn stage(magnetite stage)is the main period of the mineralization of magnetite and other ore minerals,and is the main mineralization stage of Shabao-Wawuo(copper)iron ore.The biotite granodiorite porphyry is the most closely related rock body with the mineralization.The LA-ICP-MS zircon U-Pb dating technique determines that the diagenetic age of the rock mass is 120 ± 1.8Ma(Early Cretaceous).The geochemical characteristics of the rocks show that the biotite granodiorite porphyry is a quasi-aluminum-weakly peraluminum high-kalcium alkaline series,which belongs to the I-type granite,Have the similar geochemical characteristics of adakitic rocks,The tectonic setting of rock mass formation is the extensional tectonic setting during the subduction stage of the Pacific plate,and this extensional environment is most likely related to the craton failure process caused by delamination.Fluid inclusion studies show that ore-forming fluid in Shabao-Wawuo(copper)iron ore has characteristics of middle-low temperature and low salinity.In copper iron sulfide stage uniform temperature of fluid inclusion body in quartz is 200.6?~367.2?,salinityis mainly in the range of 2.89 ~ 8.54 wt % Na Cl;in lead zinc sulfide stage uniform temperature of fluid inclusion body in quartz is 126.9?~198.7?,salinity is mainly in the range of 3.76 ~ 8.27 wt % Na Cl.From the Cu-Fe to the late Pb-Zn sulfide stage the uniform temperature of Metallogenic fluid in Shabao-Wawuo(copper)iron ore shows a decreasing trend,while metallogenic fluid density shows an increasing trend.S isotopic geochemistry of ore shows that ?34S values range between 0.88 ‰ and2.29 ‰,suggesting that the sulfur is deep source origin,including a small amount of crust sulfur,metallogenic material is mainly derived from magma.Carbon and oxygen isotope from the late metallogenic stage indicate that ?13C values range from 9.55 ‰ to 9.64‰,?18O values range from 17.89‰ to 19.89‰,calcite is mainly from the dissolved surrounding rock.Through comprehensive research analysis of the above data,Shabao-Wawuo(copper)iron deposit in Pulandian City of Liaoning Province is considered to be a skarn-type(copper)iron-polymetallic deposit and the ore-forming tectonic setting for the deposit is the extensional tectonic setting during the subduction stage of the paleo Pacific plate. |
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