Study On Tectonic Geochemistry Of Hongdoushan Copper Deposit In Yunxian,Western Yunnan

Hongdoushan copper deposit is a newly discovered copper deposit in the volcanic arc metallogenic belt of the southern Lancang river,and it has a good metallogenic geological conditions.In this paper,the geological characteristics of the ore deposit are studied by means of large scale structural rock facies mapping and indoor rock ore identification,and the structure control law is summarized.On this basis,We use the theory and method of tectonic geochemistry to establish tectonic geochemical anomalies map,delineat the key prospecting target area,summarize the deposit metallogenic regularity,and prospect prediction in the deep mine.1)Hongdoushan copper deposit is deeply controlled by fracture structure.Among them,NE-trending F₁ fracture and its upper plate Felsic alterated andesite controll the NE-trending metallogenic belt,which is the advantageous position of ore body.NWW-EW trend F₃ fracture control the distribution of nearly EW-trending metallogenic belt.NWW-nearly EW trend F₃ fault control the distribution of nearly EW trend metallogenic belt.The fracture junction of NE-trending fracture and NWW-nearly EW trend and multiple NE-trending fracture intersection are rich and thick orebody.The structure of this area is closely related to deep buried porphyry.The tectonic alteration is the exposed part of the felsic,lithopone and mud erosion zone on the periphery of porphyry.The structural strength increased from 1272 to 1220 to 1170.The alteration zone controlled by it is gradually increased from 1272 to 1220 to 1170.It is speculated that there will be multiple NE-trending,NWW-EW trend and columnar alteration ore bodies in the deep part.2)The orebody of Hongdoushan copper in Yunxian county is mainly veined and reticulated,and a small number of disseminated and blocky structures in the tectonic-alteration zone of Triassic Xiaodingxi group.The primary metallic minerals include chalcopyrite,porphyry copper,tetrahedrite,pyrite and pyroxite,Secondary minerals are mainly limonite and malachite.3)The surrounding rock alteration of the ore deposit is strong,and it mostly distribute by fracture tectonic-alteration mineralization zone.The alteration is dominated by felsic,choritization and epidotization,carbonatization and sericitization is subordinate.4)Cluster analysis and factor analysis were carried out on the tectonic geochemistry data of Hongdoushan copper mine in Yunxian county,and the combination of elements indicated that the deposit was obviously controlled by tectonic control.It's hanging wall appear high temperature?alteration?low temperature combination anomaly zoning characteristics,indicating the metallogenic fluid migration direction and occurrence of ore bodies.5)Based on the tectonic geochemical anomaly characteristics,we predicted NE-trending orebody occurrence and its extension situation.delineated the ore body controled by the NWW-nearly EW fracture in 1272 level,predicted the occurrence of ore bodies and deep extension,and it has been verified by deep drilling.The predicted copper deposits are stable to the deep,and the magmatic hydrothermal ore body controlled by tectonics has the potential of medium-size copper mine.In combination with the geological study in the deep fault zone,the hidden alkaline porphyry is found,and the deep-seated porphyry copper deposit is speculated to have a better prospect for prospecting.