Geological Characteristics And Prospecting Direction Of Mutonggou Iron Deposit In Baishan City, Jilin Province

The ore-controllin geological conditions have been proposed by studying the geologic features of Mutonggou iron ore deposit in Baishan city.Regularity of ore formation has been summarized and ore prediction model has been established.The prospecting direction of the concealed ore bodyhas been put forward.The tectonic structural background of Mutonggou iron ore deposit is the eastern part of the northern margin in North China continental plate.The iron ore deposit was occurrenced in the upper section of Yangjiadian Fm.Archaean Group.It is Anshan-type magnetite deposit and belongs to sedimentary metamorphic iron ore deposit.Eight ore bodies have been detected.No.7 is the primary ore body.Detected resource serve is 5221 kt..Currently,the detected depth is 200 to 300 m.More space of ore body may be buried beneath in the bottom.Mutonggou iron ore body is layered,phacoidal,lenticular and crescent-shaped,with the main outcropped ore of quartz magnetite and hornblende magnetite.Ore body occurs in ore-bearing buildups and conformably contacts with surrounding rocks.The structure is coordinated.According to rock assemblage,the Neo-Archean supracrustal rocks of Mutonggou iron mine is divided into five petrographic buildups,including gneiss-granulite,amphibolite,hornblende schist,magnetite quartzite and monzonitic gneiss,among which,amphibolite,hornblende schist and magnetite quartzite are ore-bearing buildups.The upper Member of the Yangjiadian Formation of Neo-Archean Anshan Group is divided into four lithologic sections.The third lithologic section is mainly composed of ore-bearing buildups,including iron ore bodies,magnetite quartzites,amphibolite and hornblende schist,which is ore-bearing horizon.Mogonggou mining area is located in the eastern tilting end of Banshigou composite syncline.The shape of ore body is controlled by fold axis.The ore body is thick in the core of antiform and synform,thin or pinch out in flanks.The ore-controlling folds and ore bodies in Mogonggou mining area represent a variation regularity of upwarping and shallow in the northwest and tilting and depending in the northeast.The ore-controlling geological conditions of Mutonggou iron mine are buildup and lithology,rock strata,fold deformation and fault.Buildup and lithology ore-controlling conditions are amphibolite,hornblende schist and magnetite quartzite.The ore-controlling lithology of iron ore body and magnetite quartzite is amphibolite and hornblende schist.Rock stratum ore-controlling conditions are amphibolites and hornblende schist of the upper member of Yangjiadian Formation of Archean Anshan Group.The fold ore-controlling conditions include the upwarping end of Banshigou inverted composite syncline structure,Mutonggou-Tangzigou secondary anticlinal structures and three-stage fold deformation structures.The fault ore-controlling conditions are brittle faults,that is,NE-trending brittle faults and near NS-trending brittle faults.The metallogenic regularity of Mutonggou iron mine was analyzed from the perspective of time,space and genesis.Amphibolite and hornblende chlorite schists were formed at the same time and their age was 2548 Ma.Mutonggou iron mine occurs in the buildups of amphibolite and hornblende chlorite schist,which represents the mineralization age of Mutonggou iron mine.The spatial distribution of the ore-bearing buildups and ore-bearing beds of Mutonggou iron mine is consistent with the variation regularity of Banshigou composite syncline.The ore-controlling folds of Mutonggou iron mine are shallow at the northwest end due to upwarping but deep at northeast end due to titling.The country rocks of amphibolite and amphibole chlorite schists are mainly composed of basic volcanic rocks and volcaniclastic rocks interbeded with sandstone.Mineralization is related with the eruption of basic volcano and the volcano-sedimentation of eruption interval.Silicon and iron are mainly sourced from the metasomatism of basic volcanic rocks and seawater.The regional metamorphism and deformation occurred make silicon and iron further enriched and mineralized.The genetic type of Mutonggou iron mine is Argoma sedimentary metamorphic type.Five markers for ore prospecting were proposed,including stratigraphic prospecting marker,rock-buildup prospecting marker,fold structure prospecting marker,metamorphic deformation and magnetic anomaly prospecting marker..According to the ore prediction theory,it summarizes the geologic body,surface,as well as mineralization features of Mutonggou iron mines.Based on aeromagnetic and magnetic anomaly,it also formulates the ore prediction model of Mutonggou iron mines.The prospecting direction and metallogenetic prognosis area in the deep-seated range of Mutonggou iron deposit have been proposed based on the ore prediction model.