Synthetic Information Metallogenic Prediction In Taerqi Area,Notrhern-central Daxing’anling Mountain

Ta`erqi survey area is located at Medium-northern part of Daxing’anling Mountain, which isaccretionary continental edge of the southeast margin of Siberian plate. Regionally, thismetallogenic belt is a superimposed part of ancient Asia metallogenic domain andCircum-Pacific metallogenic domain, and it is also a significant nonferrous and noble metalmetallogentic province in China. Depending on our survey, it suggests that Ta`erqi area hasperspectives for poly-metal Pb-Zn-Ag mineralization. Owing to the lack of basic geology andmineral exploration study, medium or large ore deposits are rarely discovered in this area.Recently, with the increasing investigation of exploration and the deepening of the researchdegree, a breakthrough has been made. On the basis of mineral resources geological survey of1/50000, we comprehensively analyze the characteristics of geological, geophysical,geochemical and remote sensing information about this area, find out metallogenic settings andfactors controlled ore forming, summarize the rules of the mineral resource distribution, chooseeffective method of synthetic information and metallogenic prognosis, todelineate favorablemetallogenic potential areas and orient the prospecting area, which will be guide for thefollowing work on ore exploration.The main strata in this area are:1) Neo-Proterozoic Qnj, Ze;2) Mesozoic J2tm, J3mk, J3mnand J3b;3) Cenozoic, Qp3d and Qh. Magmatic activities in this area are divided into two period:the one is in Late Paleozoic and the other in Mesozoic. The former is charactered by intensemagmatism with outcrops of Carboniferous and Permian granite; the latter is reflected involcanism, whose lithology is medium-acidic volcanic rocks, along with medium-acidicdyke,which is closely related to Yanshanian mineralization. The structures of northeast controlthe rock and ore body, and the secondary northwest and northeast faults provide channels forfluid and place for ore forming. According to mineral deposits discovered, we consider that thejoints of NE and NW structures are the favourable metallogenic position.Soil geochemical anomalies are directly or indirectly reflection of mineralization. It has theimportant indicative function on regional mineral deposits prospecting and mining area and itsperiphery prospecting and so on. Secondary halo in Ta`erqi displays evidently abnormal element assemblage. The most significative abnormal element assemblage is Pb-Zn-Ag. When abnormalelements superimpose well and anomaly be a large scale, the abnormal assemblage can be aneffective tool of geochemical information for metallogenic prognosis. With the obvious controlof NE structure, soil geochemical anomalies are north-eastern stretching belt as a whole. Themain abnormal assemblage is Pb-Zn-Ag-Mo, which coincides with chief prospecting mineralvarieties in this area.The magnetic suspectibility of the rock this area differs obviously, with the intensity of afew to1000(-5SI). Different rocks correspond to different suspectibility, which can indicateboundary of different lithology in geological mapping. It is an interferential factor thatsuspectility of volcanic rocks ranges largely. Susceptibility of rocks is low, with the value of±2%,but resistivity shows the characteristics of high value. Basis on the RS, this area widely developsring and linear structures, which include NE,NW,NS and EW forming the structure framework ofthis area. Ring structures mainly infest forming the loop-de-looping and overlapping rings, andsometimes occurred alone as a large ring. Ring structures are correlated to faults, volcanoactivity and magmatism, to be a important mark on metallogenic prognosis.According to the study on Taerqi1/50000synthetic information and analysis of geologicalcondition of mineralization, geochemistry, geophysics and RS, the author makes a metallogenicprognosis and delineates10different grades of prospects which contain4points in gradeⅠ,5points grade Ⅱ, and1points grade Ⅲ. Based on the above, in combination with thecomprehensive information of1/10000geological mapping, soil geochemical, high-precisionmagnetic measurement, IP intermediate gradient and cross section, contrasted with typicaldeposit propecting pattern, a metallogenic prognosis of1/10000has been made. After forecastingthe favourable metallogenic positions, we perform the engineering check of prospecting trench,consequently control4rock veins, which all underwent alterations of silicification, sericitization,pyritization and choritization. The analysis of chemical samples measurement show that Pb(highest to0.36%) and Au have reached cut-off grade, and Ag and Zn also have the evident markof mineralization.To summarize,4ore occurrence have been discovered in Ta`erqi, they areDanangou Pb-Zn-Ag-Au, Xiaonangou Mo, Sugehe Au-Ag-Zn poly-metal and ZhongxingouAu-Cu spots.This work embodies the feasibility and availability of the synthetic information in themetallogenic prognosis in Ta`erqi, which guides the further prospecting in Ta`erqi.