Geochemical Characteristics And Prospecting Criteria Of Basalt Type Copper Mineralization In Zhuziqing,Yunnan

In this paper,the basalt type copper deposit of Zhuziqing,Yun Nan,is taken as the research object,and the systematic field geological survey and indoor sample analysis are carried out.Based on the previous research data,the regional geological background and the stratum characteristics of the mining area are analyzed,and the rock mineral identification is carried out,elemental geochemistry,stable isotope geochemistry,has achieved the following new understanding:(1)The Permian basalt strata in the study area are well developed and characterized by mineralization.The ore-bearing strata are the upper part of the Permian Minshan basalt group(P3e5).The lithology is mainly almond-like basalt,stomatal basalt,and patchy.Basalt and dense basalt.The ore body is poorly exposed on the surface,and its shape is lamellar and veiny.The mineral composition is complex.The ore minerals include natural copper,porphyrite,chalcopyrite,copper blue and malachite.The gangue minerals are mainly attapulgite,pyroxene,chlorite,quartz and feldspar.The ore has a metasomatic structure,a solid solution separation structure,a vein structure,a disseminated structure,and a variegated structure.The mineralization of surrounding rock is obvious,mainly including green curtain petrochemical,silicification,chlorite,carbonate,and petrochemical.Among them,the most closely related alteration to mineralization is petrochemical and silicification.(2)The geochemical characteristics of the main elements indicate that the Na2O content in the alteration zone is higher than that of the surrounding rock;the content of Al2O3,CaO,TTe2O3,MgO and TiO2 in the surrounding rock is higher than that in the alteration zone,while the content of CaO and MgO in the ore is lower..The reason for this difference may be related to the alteration combination in this area.The loss of copper ore is higher than that of the altered zone,which may be related to the high content of organic matter in the ore.The lower content of CaO and MgO in the ore indicates that the content of carbonate in basalt is low.(3)The geochemical characteristics of trace elements indicate that the main enriched elements of the surrounding rocks are Rb,Ba,U,K,etc.The copper ore is mainly enriched in Cu and W,and the elements such as Rb,Ba,K,Sr and Y are depleted,indicating that the basalt has suffered.The post-alteration effect is strong.From the surrounding rock to the ore,the content of Cu and W is obviously increased,and other elements are mostly loss or change is not obvious,so W can be used as an indicator element of copper mineralization.(4)The geochemical characteristics of rare earth elements show that the slopes of the light rare earths distribution curve and the heavy rare earth component curve are roughly the same,and it is inferred that they have the same source and tectonic background.The characteristics of rare earth elements are characterized by smooth right-dip type,light rare earth element enrichment,heavy rare earth relative loss,and ore rare earth enrichment is lower than surrounding rock.There is a certain negative correlation between Cu and ∑REE,LREE and HREE,and the changes of ∑REE and LREE are consistent,indicating that the REE and LREE are enhanced with the enrichment and migration of Cu.Although HREE also migrates with the increase of Cu content,The degree of migration is low,indicating that the LREE enrichment in the ore-forming process is stronger than the enrichment of HREE,and the ore-forming fluid is also beneficial to the migration of LREE.(5)In the C-O homolog analysis,the δ180smow and 613CvPDB are characterized byδ18OSMOW and δ13CvPDB,respectively,which are 8.15～20.18‰ and-7.21～-17.19‰,respectively.The source of carbon is mainly related to biological activities and underlying carbonate formation.(6)The basalt in the overturned village area is obviously controlled by the NE-trending fault,and there are more mineralized outcrops in the wild.The comprehensive research area has geological data,geophysical and geochemical data,remote sensing information and the ore-forming characteristics of the adjacent basalt type copper deposits.It is believed that there is potential for basalt type copper ore prospecting in the overturned village area.The direct prospecting signs in the wild are ancient mining relics such as natural copper,peacock petrochemical,copper blue,and old man.