| The Jinshantun mineral survey region is geographically located at Fenglin Forest Farm of Yichun,Heilongjiang Province,and tectonically located at the eastern edge of the Songnen block.Geological surveys and studies show that this region mainly develops early Cambrian strata of Qianshan formation,Late Permian porphyroid monzonitic granite,Late Triassic biotite monzogranite,and granite porphyry.The nappe structure is a regional rock-controlling ore-controlling structure,the S-N and NNE extending structure alteration zones are closely related to the gold polymetallic mineralization.The gold polymetallic ore bodies are mainly vein-like and fine-vein-like,controlled by the NNE-trending structure.The metal minerals in the ore mainly include pyrite and chalcopyrite,magnetite,sphalerite,galena,and the non-metallic minerals are mainly quartz,chlorite,calcite,potash feldspar,and a small amount of biotite.Such wall-rock alterations as silicification,potash feldsparization,sericitization,epidoteification,chloriteization,carbonation and skarnization are common in mineralized bodies and their wall rocks.Preliminary research suggests that the type of gold polymetallic mineralization in the area is a contact metasomatic type(skarn type)that has a close temporal and spatial and genetic relationship with the biotite monzonitic granite.The high magnetic anomalies in the study area extend in NNE-direction,and the IP anomalies generally show low resistance and high polarization.The water systemsediment survey of 1 ? 50000 in the study area indicates that the element composite anomalies are mainly composed of Au,Ag,Cu,Pb,Zn,As,Sb,W,and Hg.They have obvious concentration zoning,concentration centers and well element fits.Moreover,each element in these anomalies has a middle zone,and Zn anomaly has an large-size inner zone.The results of 1 ? 10000 soil geochemical surveys in the region show that the anomalous combination elements of Zn,Pb,Ag,Cu and other elements have obvious concentration centers,high anomaly intensity and well fit,which are coincided with the polarization anomaly.Based on the extraction of favorable ore-forming geological conditions,geophysical high-precision measurement,soil geochemical measurement and other prospecting information,the gold-polymetallic ore-prospecting indicators in the area are summarized,and comprehensive information mineralization prediction work is carried out.One?-level ore-prospecting region has been determined.According to the ore-prospecting potential evaluation of the region,one ore-exploration target has been optimized selected.The large-scale geophysical and geochemical exploration delineates 249 single-element soil anomalies,and 22 soil composite anomalies,one high magnetic anomaly,two fracture structures,one resistivity anomaly and four polarizability anomalies.Due to trenching engineering verification and deep drilling engineering control of discovered ore bodies,some ore-exploration results have been carried out including one mineralized alteration zone,three lead-zinc(copper)ore bodies,three lead ore bodies,five zinc ore bodies,one gold ore body,and thirteen lead-zinc mineralization bodies,five gold mineralization bodies.These are very helpful for further geological ore-prospecting. |
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