| Nenjiang ChengGong Gold Deposit in Heilongjiang Province is located in the DaXingan Mountains arc basin system in the eastern part of Tianshan-Xingmeng orogenic system,and at the junction of Zhalantun-Dobaoshan island arc belt and Hegenshan-Heihe OPHIOLITIC MELANGE belt.It is located in the southwest part of Nenjiang Heihe metallogenic belt.Cataclastic breccia ore body mainly existed in Early Carboniferous and Early Carboniferous Shizheng granite mylonite contact parts in the ore position in the combined concentration center position abnormal,with branches and pinch reproduction characteristics.I-7 orebody is the largest major gold orebody in this area.Its gold and metal resources account for about 99% of the total gold and metal resources,which is the main object of this study.The host rocks are mainly silicified and pyritized fractured breccia,followed by silicified,pyritized granitic mylonite and dioritic porphyry.Metallic minerals are mainly pyrite,followed by a small amount of pyrrhotite and galena.The alteration of surrounding rocks is mainly silicification and pyrite mineralization,followed by sericite.The orebody is strictly controlled by NE trending cataclastic breccia zone control.Due to the intrusion of late granite porphyry and diorite porphyrite,the head area near the ore body was destroyed.Mesozoic dike rocks are well developed in the area,and diorite porphyry is closely related to ore bodies.This is not only reflected in the fact that some dike rocks are associated with ore bodies in space,but also constitute the main rock types in the mining area and play the role of host rock.It is obvious from the section maps and geological section maps of different elevations that the diorite porphyries are distributed on the upper wall of gold orebodies,and their thickness varies from 2 to 5 meters.Most of the veins are gold mineralized and a few ore bodies are formed.From 400 meters to 50 meters,i.e.from shallow to deep,the length and thickness of dioritic porphyry dikes gradually increase.Under 100 meters,most of them are irregular veins,some are rock-branched,and there may be dioritic porphyry stocks in deep.According to speculation,Diorite porphyry magma provides hydrothermal and partial ore-forming materials for the formation of gold deposits.It is presumed that in the late Early Cretaceous,accompanied by a large amount of magma and hydrothermal ejection from the surface,some of them were injected along the pre-formed NE-trending structural fractures,which cemented the surrounding rocks into altered fractured breccia ores.Some silicified mylonite type ores are formed by individual irrigation along mylonite.The formation of vein rock and ore body accompanied by the phenomenon.Soil anomaly in geochemical survey Au,Ag and Bi have inner zones and are well integrated with each other,accompanied by elements combination of Cu,Pb,Zn,As,Sb,W and Mo.Larger portfolio anomalies.Generally,the apparent polarizability anomaly with band distribution is about 1.1-1.4% in amplitude,and the medium-intensity resistivity anomaly with band distribution is about 1100-2000.?.m in amplitude.Through summarizing the geological and geophysical and geochemical characteristics of ChengGong Gold Deposit,the next prospecting direction is to searching for target areas with similar characteristics in regional metallogenic belts and to tracing the depth of ore body. |
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