Geochemical Exploration and Prospecting Direction of Copper-Gold Deposit in Eastern Pochengshan of Beishan,Gansu Province
The copper-gold deposit in eastern Pochengshan is located in the Fe-Cu-Au-Pb-Zn-Mn-W-Sn metallogenic belt of Cihai-Gongpoquan and the gold-silver(Cu-Pb-Zn)pyrophyllite metallogenic sub-belt of Pochengshan-Yushishan.Historically,a 1∶50 000 scale regional geological survey and a 1∶50 000 scale mineral survey have been conducted in this area.These surveys have facilitated the preliminary identification of the regional stratigraphic sequence,the chronology of intrusive rocks,and the interrelationship between structural features and mineralization processes.Additionally,two comprehensive anomalies have been delineated based on 1∶50 000 scale stream sediment analysis.However,the extensive anomalies of gold and copper identified through the sediment survey in the Pochengshan river system have not been thoroughly investigated in previous studies.To further clarify the geochemical characteristics and prospecting potential of gold and copper,1∶10 000 scale cuttings survey was conducted in the area.R-type cluster analysis and correlation analysis indicate that Au and Cu are the primary metallogenic elements,exhibiting significant metallogenic potential.Based on the metallogenic geological background and the elemental combination characteristics of the study area,four comprehensive anomalies were delineated through a 1∶10 000 cuttings survey.Among these anomalies,two comprehensive anomalies were selected for detailed verification.The Ay-3 anomaly area of 0.48 km2,with the primary anomalous element being gold(Au),exhibiting a mean concentration of 53.01×10-9,a peak value of 1 000×10-9,and a contrast ratio of 17.67.The Ay-4 anomaly area of 0.35 km2,with copper(Cu)as the primary anomalous element,showing a mean concentration of 881.22×10-6,a peak value of 10 000×10-6,and a contrast ratio of 27.53.The gold orebody and copper orebody are located in regions 1 and 2,respectively.These orebodies correspond closely with the delineated comprehensive anomaly.Geochemical analysis of rock debris indicates that the area holds significant potential for gold and copper deposits.The newly discovered gold orebody is situated within a fault zone where mylonitized granodiorite is in contact with the wall rock,and it is controlled by an east-west fault structure.The mylonitized granodiorite may serve as a crucial source for the copper-gold deposit.The contact zone between the late Silurian mylonitized granodiorite and the green mud quartz schist fracture of the ancient Dongjing Group of the Changcheng system is considered as the main prospecting direction in the future.
altered rock type gold depositdebris geochemistrymetallogenic regularityprospecting directionBeishanGansu Province
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维普
