| The Smitas Taishan area is located in the Siberian plate and the Junggar plate between the Paleozoic Sawuer-Alman too complex island arc.However,there is no systematic study on the geochemistry of volcanic rocks.In order to accurately understand the constraints of mineralization on mineralization,this paper has been widely used in the field of volcanic rocks.In the middle of the area selected as the focus of the study area.The volcanic rocks in the area are typical of the Amesan-Ianite assemblage,among which the volcanic strata of the Hugelstite Formation are the oldest and most widely distributed,which is a volcanic clastic rock-based volcanic rocks.1.The content of Si O2 in volcanic rocks is 55.6%-67.78%,the content of K2 O + Na2 O is2.78%-7.80% and the content of Al2O3 is 16.03%-17.44%.The TiO2 content of all samples is less than 1.15%,indicating that the volcanic rocks Characteristics,MgO content is low,the value range of 0.46%-2.96%,lower than the original magma value(10.0% ~ 12.5%)[54].Correspondingly,the Mg #(Mg +(Mg + Fe)] is between 0.02 and 0.22,which is much lower than that of the original magma Mg # = 0.68 ~ 0.75,which indicates that the magma is non-primitive magma,Or by the role of magma mixed with the continental crust granite and lead to the reduction of Mg in the magma.It has the characteristics of low CaO,MgO,high,Fe2O3,P2O5 and so on,which reflects the evolution of petrochemical composition in the volcanic activity in the study area.2.In the geochemical characteristics,Zr / Nb = 18.4~25.5(all greater than 10),Hf / Th =0.60~1.33 and Zr / Y =5.5~9.4,all of which show that it is formed with the island arc Volcanic environment is quite [54].Th =3.5~11.9?g / g,La = 15.2~27.5?g / g,Hf / Yb =1.4~2.4?g /g,showing the island arc and continental margin of Andesan nature.Nb,Ta and other high field strength elements and heavy rare earth elements relative loss,Rb,Ba,Th,U,K,P and other large ion lithophile elements and light rare earth elements relative enrichment,showing Nb,Ta,Ti negative anomalies,show Geochemical characteristics of island arc volcanic rocks.The Nb content of the volcanic rocks is 5.53-13.36×10-6,the average is 8.98?12×10-6;Nb /La?0.7×10-6,La / Ta> 15×10-6,Th / Nb> 0.7×10-6,The source magma is the continental margin arc magma associated with the subduction.The volcanic rocks of Ta / Hf are less than0.5×10-6,showing the basic characteristics of island arc calcareous volcanic rocks.3.The relatively enriched elements in the region are Cu,Zn;the relative depleted elements are Ag,Pb,Au.The enrichment coefficient(K)of the above five elements isbetween 0.001-1.43,and is divided into the depleted element according to the standard of K<0.9,0.9?K <1.1,1.1?K?1.3,K> 1.3 Elements,enrichment elements and strong enrichment elements.From the relative Clark values,the enriched elements in the zone are Cu,and the relative depleted elements have Au,Pb,Ag and Zn close to the Clark.Through the analysis,it can be determined that the volcanic rocks of the Devonian Huigirster Formation are the ore-bearing layers for the formation of magmatic copper deposits.4.According to the excavation works of the Ao Baosi Formation in the upper section of the Huojirister Formation,the surface of the excavation is 2,which is the object of the Aobao West I,the Ou Baixi ? ore body,the copper body In the middle of the Devonian group,the Alpine rock tuff,the diorite porphyry veins.The copper ore body is silicified and fractured Ansan tuffstone rock.The copper mineralization is mainly malachite petrochemical,the geochemical characteristics of volcanic rocks in the area and the copper mineralization point,which reveals that the study area is a favorable copper mineralization prospecting area The?5.Based on the systematic analysis of the Devonian volcanic rock mass,the rock characteristics,rock geochemistry and mineralization elements in this area are summarized,and the mineral assemblage index of the Devonian volcanic rocks in the middle reaches of Taibai County in western Junggar is summarized. |
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