Geological Characteristics And Metallogenic Prognosis Of The Shijiatun Gold Deposit,Jilin Province

The Shijiatun gold deposit is 22km southeast of Erdao District in Changchun city.The administrative area is under the jurisdiction of the town of Quannongshan,and the traffic is very convenient.The tectonic position of the region is located in the tectonic belts of the hyperplasia of epicontinental of the ancient North China continental block and the ancient Siberia continental block.In the area,the strata are mainly has the yufutun formation of the Lower Carboniferous,the yangjiagou formation of the Upper Permian,the anmin formation of the Upper Jurassic,and the holocene of Quaternary.The main magmatic rocks are:the dongliusha sequence in the middle Jurassic period?xinlitun unit?;the quanyan sequence in the late Triassic period?zhoujiayao unit,nanquanyan unit?,and the andesite cryptoexplosion breccias of dajiangjiatun.The magmatic activity in the area is more frequent,the structure is complicated,and the alteration mineralization is developed.The shijiatun gold deposit is located at the southern tip of the east wing of lanjia synclines,northwest-west orientation fracture structure,it is located in the area of the band of xiaoshijiatun-chenpingfang in the working area,relatively large scale.This structure cut yufutun formation where the orebody is located.The geomorphologic expression is lanjia river passing through in the area.Be influenced by the synclines structure and the northwest-west orientation structure,it form secondary interlamination detachment fracture structure,providing favorable passageway for the late magmatic hydrothermal invasion and migration,also is the most favorable metallogenic position.The fluid inclusion research of Shijiatun gold deposit shows that the main metallogenic temperature range is 240.3-330.2?,salinity range is 2.06-12.31 wt%NaCl,fluid density is 0.87-1.04g/cm³,metallogenic pressure is 7.21-15.94Mpa,depth is 0.72-1.60km.Uniform temperature 240.3-330.2?represent a typical mesothermal deposit,and near ore surrounding rock alteration silicification-phyllic zone reflect the middle?low?temperature hydrothermal alteration,the main gold bearing minerals arsenopyrite-pyrite-magnetic pyrite-chalcopyrite-sphalerite-galena is a set of typical mineral combination of middle temperature,mineral deposit controlled by interlamination fracture zone,the type of mineral deposit is a typical mesothermal vein type gold deposit.There are four gold ore bodies in this work,the orebody numbers are?1???1?-1??1?-2??2?,including?1?orebody mainly orebody,this time only research?1?orebody.The ore body is a regular vein,it is520m long,45-450m inclined deep in the mining area,the average thickness of 2.69 m,the average grade 3.34×10^-6.The south of the mine is rich,the north of the mine is poor,and is a hidden orebody.In the case of the higher research degree of the shijiatun deposit,it is expected to obtain new findings on the periphery.Based on study on geological conditions and deposit genesis of gold,the prospecting geological information extraction,and combining with the geophysical chemistry anomaly characteristics,delineating dinianzhang-xiaomoujiagou and zhoujiayao prediction area as the favorable prospecting target area,in the peripheral of shijiatun gold deposit.It is expected to find a new orebody consistent with the genetic type of shijiatun gold mine.