Characteristics And Ore Bearing Characteristics Of The Volcanic Rocks Of The Late Carboniferous Tugutu Braque Formation In The East Tianshan Mountains

Jueluotage tectonic belt is the Carboniferous volcano sedimentary strata outcropped strata as a symbol of the volcano rock bands which is in the South Tianshan block,north margin of the Tuha basin,tectonically located in the Tarim plate and Junggar plate junction,is an important part of the Central Asian orogenic belt.However,there are still disputes about its formation environment,which directly leads to different views on the characteristics of the late Paleozoic evolution of the Tianshan tectonic system.The Tugutu Braque group in the East Tianshan is located in the Yanmansu volcanic basin on the south side of the Jueloutage tectonic belt.The whole area is long strip,and there are certain natural copper mineralization points and mineralization clues.The research significance of this group of volcanic rocks is to understand the geological characteristics and formation environment of volcanic rocks in the study area,so as to solve the tectonic background of the Carboniferous in the Jueluotage belt of the eastern Tianshan Mountains,and to evaluate the natural copper bearing capacity of the Tugutu Braque formation in the eastern Tianshan Mountains.Based on the previous research,the ancient volcano rock of Tufutu Braque group as the research object,in the identification of temporal and spatial distribution of the volcano rock group,geological data and results of previous research area,through petrographic and geochemical methods,rock assemblages,stratigraphic sequence and eruption rhythm and the use of geological profile determination of volcano rock,petrogenesis and tectonic environment analysis and Research on the volcano rocks of natural copper mine area,made the following conclusion:1.The volcanic rock assemblages of the TugutuBraque group in the eastern Tianshan janrotagu group are basalt-andesite-angolanite rhyolite and the same composition of medium-acidic volcanic tuff,which are mainly subalkaline series,with no continental rift and Shuangfeng type volcanic rocks.Natural copper is mainly enriched in three basalt and a small amount of tuff.There is a good correlation between the SiO₂ and the various oxides.The trace elements of the basalt and the rhyolite are similar to the rare earth elements,and the microcurves of andesite have many solutions,which may be related to the formation of the environment.The lower Nb/La,Hf/Th and higher Th/Yb and Th/Nb in Xuan Wuyan conforms to the characteristics of the collision shaped arc region Xuan Wuyan,with the Xuan Wuyan attribute of the rear collision,and the characteristics of the post collisional granites of the anganite rhyolite.2.The JueLuotage basalt area natural basalt copper mineralization belt in the central Heijianshan basalt in zircon SHRIMPU-Pb age 306.2±4.0Ma,the Dongjianshan of East in zircon LA-ICPMS U-Pb age of 308.9±5.8Ma,ten in the west slope of Ma native copper mineralization in the ore area beach group basalt zircon LA-CIPMS age was 307±4Ma,and the zircon in the lily soil soil of ancient Eastern Braque group LA-ICP-MS U-Pb volcano rock age 303.7±2.3 Ma,indicating the JueLuotage area of ancient volcano rock Tugutu Braque group is integrally formed in late carboniferous.3.There is subduction process in the Carboniferous of Eastern Tianshan.There is a post collisional tectonic evolution stage in the northern part of Xinjiang in Late Paleozoic.The subduction collision event may end in the Late Carboniferous.Combined with the existing research results,it is thought that the subduction and compression process in J JueLuotage structural belt has ended and entered the stage of post collision tectonic evolution.The Tugutu Braque Formation volcanic rocks should be formed in the extension stage of post collision tectonic stage.4.The thickening lithosphere in the early stage of the Jue Luotage area has undergone the delamination,and formed a basalt with high abundance.The basalt is formed in the rift environment of the water and land,and is the main source bed of the natural copper deposit.The study of the basalt type natural copper mineralization in the Jueluotage area indicates that it may be the product of the post collision lithosphere delamination and has nothing to do with the mantle plume activity.The mineralization of natural copper in basalt is a metallogeny after magmatism,and has no significant relation to the action of the mantle plume.Basalt type natural copper has good prospecting potential in this area.