| Tugurige gold deposit is located in the western Inner Mongolia Urad Zhongqi,tectonically located in the northern margin of North China plate,the Central Asian orogenic belt,the Xing Meng orogenic belt.In the study area in the early Paleozoic,the paleo Asian Ocean subduction accretion phase,with the closure of paleo Asian Ocean in the late Paleozoic in the Permian extinction,entered by extrusion into extensional tectonic setting of post collision extensional stage.Mining area exposed strata are mainly the upper figure group of Lower Proterozoic baeyin and quaternary.The fracture structure of the mining area is controlled,and the gold vein is controlled by brittle fracture of the whole North west.The magmatic rocks in the area are relatively developed,and appear from acid rock to basic rock.The dating shows that the formation of the Middle Permian quartz diorite is the latest,with an age of 266+ 2Ma.The research that the early Permian porphyritic granite and two quartz diorite and gold mineralization is closely related to the Middle Permian pyroxenite and amphibolite gabbro and Cu Ni mineralization is closely related.Based on the regional data and tectonic discrimination diagrams,it is considered that the quartz diorite is the product of magmatic activity under the background of regional post collisional extensional tectonics.With the vein gold ore body shape is NW-SE distribution,ore mineralization types in the ore bearing quartz vein type,followed by altered rock type.The ore structure mainly consists of unequal grain structure,inclusion structure,solid solution separation structure,metasomatic ring rim structure and cataclastic structure.Ore structures are mainly vein structures and sparse disseminated structures.The ore minerals are mainly pyrite,chalcopyrite,galena,sphalerite and natural gold,and a small amount of tellurium gold,tetrahedrite and covellite.The main types of wall rock alteration include potassium,silicification,yellow gold mineralization,green mud,petrochemical,epidote,sericite,carbonate and so on.Among them,silicification and yellow gold mineralization are most closely related to gold mineralization.According to the geological characteristics of the ore bodies,mineral structure and mineral light sheet under microscope with relations,mineral assemblage and formation sequence,the hydrothermal mineralization period is divided into four metallogenic stages: Quartz ankerite and quartz stage(I)-Ming gold pyrite stage,quartz-(II)the gold polymetallic sulfide stage(III)and quartz carbonate stage(IV),the second and the third stage is the main stage of gold mineralization.The ore deposits developed large amounts of iron,dolomite and gold,in which dolomite is the product of early stage of mineralization,reflecting a high degree of oxidation of poor S2-environment.In the early stage of iron ore dolomite,the main mineralization stage and late stage quartz were analyzed,the study of fluid inclusion body test results show that the ore forming fluid of CO2-H2O-Na Cl system,in the process of mineralization occurred obvious fluid immiscibility.The homogenization temperature peak in three stages respectively is 320 to 340 DEG C,240~ 280 and 240~250 DEG C;salinity peak were 8~9 wt%Nacl.eqv,4~7 wt%Nacl.eqv and 1 ~ 2wt%Nacl.eqv;the peak density were 0.74~0.78 g/cm3,0.84 ~ 0.88g/cm3 and 0.92~1.00g/cm3;with middle temperature,low salinity,low density characteristics.During the main metallogenic stage,the ore-forming pressure is from 70 to 114 MPa,and the metallogenic depth is from 6.78 to 8.86 km,with the characteristics of medium depth.The results of hydrogen,oxygen and sulfur isotopes show that the ore-forming fluid mainly consists of primary mantle water,and later meteoric water is added.The ore-forming material mainly comes from mantle.In summary,the genetic types of gold deposits in Tugurige mesozonal orogenic gold deposit.Summarized the gold deposit mineralization regularity,that the tracking control of fractures of gold veins are strictly controlled by NW and NWW to the 2 groups formed in the same stress field,the difference along the cracks of the 2 groups formed 2 groups tracing vein occurrence difference,specific performance: NW veins tracking NW cracks more NWW to crack longer,NWW veins tracking NWW fracture to fracture to longer than NW;the same group to approximate parallel veins,the distribution of ore bodies in the direction and dip with a horizontal obvious relation;the distribution of ore bodies with piecewise enrichment rules and lateral trending law to the veins in NWW to NW parts and parts of NWW to dip enrichment mineralization;ore veins in NW to the site and steep parts of mineralization;NW to NW orebody to lateral trending,NWW to NWW to the orebody to side side angle are smaller V,V.The stress analysis of ore control structure shows that the fractures of NW and NWW follow the two directions respectively,which have the characteristics of sinistral pressure,torsion and dextral tension.To sum up,the focus of prospecting should be in the deep NWW position of the NW section and the second section of the vein in the lateral direction of the lode.Exposed several basic ultrabasic rocks in Tugurige gold mining area,and copper nickel mineralization was found in individual rock mass.The ore bearing rock mass is mainly middle coarse grained pyroxenite.Pyroxenite zircon dating results show that,the rock forming age of 273.5~274.4Ma;the tectonic discrimination diagrams show pyroxenite formation in the North China plate and the South Mongolia block after the collision extensional environment;magnetic north is the ore bearing rock has higher continuous wide range of abnormalities,reflecting the region may have concealed rock mass exist.In conclusion,there is a potential for further prospecting for copper and nickel in this area. |
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