Geological Conditions And Prospect Evaluation Of Gold Deposit In Xindonglinchang Area Of Yichun City Heilongjiang Province

The xidonglin field area of yichun city,heilongjiang province is located at the junction of xiaoxinganling-zhangguangcailing polymetallic metallogenic belt and jiamusi uplift metallogenic belt.Combined with the comprehensive information of geological,geophysical and geochemical characteristics of the working area,it is believed that gold prospecting in this area has a superior prospect.Characterized by:The work area located in Inner Mongolia hinggan mountains geosynclinal fold zone(?),yichun,prolong life geosynclinal fold system five star-GuanSong town middle uplift belt(II)and the joint of the jiamusi uplift belt.This area has a long geological history,complex geological structure,and developed metamorphism,volcanism and magmatism.The working area is divided into ten groups of petrostratigraphic units from old to new.The dongfengshan rocks in the paleoproterozoic,such as sericite quartz schist,magnetite-quartzite or magnetite-penetration-quartzite in the lithosphere,are the main occurrence horizon of gold deposits.It is also an important sign of gold mining in this region.Magmatic rocks are relatively developed in this area.It was mainly in the late Triassic period.Magmatic activity can be directly mineralized to provide source and required hydrothermal fluid,It can also indirectly provide heat source and hydrothermal solution for mineralization and necessary dynamic conditions for the formation of metal mineral.There are dongfenglinchang gold deposit and dongfengshan gold deposit in this area.The ore body of dongfenglinchang gold deposit is stratiform,It is in contact with surrounding rock.There are 6 ore bodies of different sizes and 6 subordinate ore bodies in the deposit.The ore body is 25-157 meters long,Average vertical thickness 0.7-6.28 m,Extend 7-278 meters along the trend.There are alteration and mineralization caused by hydrothermal activity in mining area.There are silicification,sericitization,carbonation,pyritization and magnetopyritization.Among them,magnetopyrite mineralization is closely related to gold ore genesis,and has multi-period.The formation of dongfenglinchang gold deposit is controlled by space and time,and volcanic material(medium base eruptive rock)is the main source of source gold.A set of sedimentary strata composed of sandy,silty,argillous,siliceous,iron and carbonate mixed with meso-basic volcanic rocks is deposited in the Precambrian ocean basin of dongfeng forest field.These strata,after regional metamorphism and after heating metamorphism,form a set of shallow metamorphic rocks composed of schist(embedded magnetite quartzite thin layer or lentil body)and marble.In rocks,iron,silicon,manganese,arsenic,and gold are enriched,activated,migrated,and accumulated in some layers to form gold,iron or its composite ore body.Some gold was reenriched by thermal metamorphism and transformed into sedimentary metamorphic gold deposits.To study geological features of the dongfenglinchang gold deposit,The gold deposits occur mainly in schist or magnetite quartzite and its lower surrounding rocks of dongfengshan group.The aeromagnetic anomaly is obvious in the aeromagnetic anomaly area.The high magnetic anomaly gradient in the gold mine area is large,the abnormal values are positive and negative,and the morphology is very disorderly.The value is around 500 nT.The sediment anomalies of the drainage system consist of Au,Ag,As,Cd,W,Pb,Bi,etc.High background areas of gold and arsenic geochemistry.Soil anomaly pattern: Abnormal composition of Au and As major elements.Fe-Si-Mn-As is positively correlated with gold,It is a combination of indicative elements in this area.According to the study of the geological conditions and characteristics of gold deposits in xindonglinchang area,Set up a prospecting model,In combination with the achievements of land,material and chemical exploration in the study area,In this area can be delineated Daqingchuan(?)and the chariot of the Suliantun(?)two good looking for the key of gold mineral prospecting target areas.The geological background of the target area is the palaeoproterozoic dongfengshan group.Invaded by late Triassic intrusive rocks.The aeromagnetic value is between 300 and 500 nT,Water system anomalies are dominated by Au and As.It has a good metallogenic geological background.The two target areas are considered to have great gold polymetallic mineralization potential.It is a promising location for the search for gold-polymetallic minerals.