Discussion On The Geological Characteristics And Genesis Of The Cu Pb Zn Polymetallic Deposit In Mian Lue Yang Area,Shaanxi

Chenjiaba mine is located in Shaanxi province(county)– Mian~Lve ~Yang on the north side of the central triangle of the ancient basement suture belt,a plurality of minerals have been found in the area(change),showing good metallogenic potential.Previous studies have been carried out on the structural geochemistry of,petrology and volcanic edifice in this area.However,there is still a lack of theoretical research and the genesis of the deposit.Therefore,this paper takes chenjiaba deposit as the research object,based on field investigation and indoor comprehensive study,starting from the analysis of strata,lithology,structure,rock geochemistry,through test analysis of pyrite trace element and Rb~Sr isotope test,C ~ H ~ O isotope analysis and S isotope geochemistry analysis,metallogenesis geological characteristics and volcano rock formation,reveal the physical and chemical conditions of mineralization and ore material source,summed up the ore source bed,in the transformation process of driving force and in~depth understanding of the genesis of the deposit is put forward,prospecting criteria and prospecting further provides new evidence.The main achievements are as follows:1.Chenjiaba Cu Pb Zn polymetallic deposit,showed that the trace element geochemical characteristics of dolomite: the ratio of(SiO2+Al2O3)/(MgO+CaO)(<0.1),small and silicified dolomite(SiO2+Al2O3)/(MgO+CaO)ratio is 6.12 on average,far greater than 0.1,and the ore ~ rock silicified dolomite,it can be inferred that the enrichment of dolomite is not conducive to the copper content of REE;Nb,Zr,Th and other elements in the silicified dolomite is much lower than the Clark values of crust,similarity,and sedimentary carbonate rocks that trace element assemblage chenjiaba deposit silicified dolomite with sedimentary characteristics of carbonate rocks;Delta Ce in little change during the diagenetic process,most of the silicide dolomite sample Eu positive anomaly and LREE enrichment,showed that the silicified dolomite in the area close to the open sea(Ocean)basin environment,influenced by hydrothermal activity in the process of forming.In quartz keratophyre SiO2~K2O diagram,the projection point falls mainly in the high potassium calc alkaline series range,reflecting the potassium rich characteristics;trace element quartz keratophyre Rb,Ba,Sr and other large ion lithophile elements such as Ta,Nb,loss of high field strength elements,implying that the magma derived from the crust or mantle contamination.2.Through the content comparison and formation material characteristics of ore ~forming elements in the formation of Bikou Group Donggouba group is the source bed of the mine,the transformation process by fracture structure effect is the main driving force of migration.3.34 S sulfide polymetallic deposit metal Chenjiaba Cu Pb Zn value(7.82‰~8.90‰)between the cause of reduced sulfur volcano(?34S 2.7~5.5×10~3)and seawater sulfur(?34S? 15×10~3),metal sulfide sulfur may be reduced sulfur and sulfur in the seawater volcano the isotopic fractionation of mixed,but mostly from seawater sulfate.The strontium isotope 87Sr/86 Sr of pyrite is close to the mean value of the strontium isotope 87Sr/86 Sr of the continental crust,which indicates that the sulfide mainly comes from the crust4 According to the three kinds of trace elements in pyrite,As~Co~Ni S isotopic characteristics,the deposit is a medium low temperature deposit,ore~forming process is relatively complex,which is related with the submarine volcano eruption and sedimentation,and volcano mineral liquid.5.The difference of Y/Ho ratio showed that the pyrite magmatic fluid mineralization in Delta 13C;dolomite ore value in-0.53 ~-0.89,Delta 13 C and marine carbonate value range is similar to that of carbon in the ore~forming fluids from marine carbonate rocks.6 Comprehensive regional geological background,mining area and whole rock trace elements,trace elements,stable isotopes of pyrite and pyrite Rb~Sr age analysis,can be considered chenjiaba sources of ore~forming material of complex mineralization with multi period,but the main formation of Yu Xinyuan in ancient times;the forming temperature of the deposit is in low temperature,early volcano sedimentation,later experienced a transformation process of tectonic stress,which belongs to the volcano sedimentary reformed deposits.