The Geochemical And Uranium Fertility Characteristics Of NeoPaleozoic Typical Granites In Eastern Junggar, Xinjiang

Supported by the subproject(Evalution and investigation on prospective of uranium-polymetal at anti-river of Wulun area in northern of Xinjiang) of project(Evalution and investigation on uranium resource of nation) established by the geology investigation bureau; using granite in Eastern Junggar as the research objective, Focusing on the part of typical granite in the study area conducted by detailed field geological survey and data compilation indoor,according to the theory of geology and geochemistry, combining petrological methods, indepth researchof geochemical characteristics, tectonic setting and genesis, uranium fertility of typical granite in study area.Gained several achievement as follows:1.Typical granite in the study area can be divided into two types of alkaline and alkaline calcium: the rocks of Saertielieke, Laoyaquan, Huangyangshan, Sujiquan,Sabei, Tasigake belonging to alkaline;having high silica(SiO2>70%), alkali-rich(Na2O+K2O>7.5 %), potassium(K2O/Na2O>1), peraluminous(ASI>1),the high ratio of TFeO/MgO(>5.3), high differentiation index(DI>93);the rock of Kubusunan,Yemaquan belonging to calc-alkaline;having low silica(60%<SiO2<70%), low-alkali(Na2O+K2O<7.5%), sodic(K2O/Na2O<1),low differentiation index(DI<80), the low ratio of TFeO/MgO(<5.3).2.The total amount of rare earth of Saertielieke, Laoyaquan, Huangyangshan, Sujiquan,Sabei, Tasigake are higher than the rock of Kubusunan,Yemaquan;having a strong negative Eu anomalies; the REE pattern is right light "V" shape; the REE patternof Kubusunan, Yemaquan is type of right-wing, Eu depletion or weak Loss.3.All rocks of the research have characteristics of enriched LILE of Rb, Th, K and high field strength elements of Zr, Hf;the rocks of Saertielieke,Laoyaquan,Huangyangshan, Sujiquan, Sabei having strong losses of Ba, Nb, Sr, Eu;and high value of high field strength elements(Zr+Nb+Ce+Y).The rock of Kubusunan,Yemaquan,Tasigake hascharacteristicsofweak loss or no loss of Ba, Sr;and low value of high field strength elements(Zr+Nb+Ce+Y).Ba of Tasigake having a positive anomaly, probably relating to melt-mixing effects of its surrounding during emplacement process.4.The rock of Saertielieke,Laoyaquan,Huangyangshan,Sujiquan,Sabei,Tasigake attributing to A-type granites,belonging to subtype A2;formed on the lower continental collision or crustal or crustal plates of arc magmatism.The rock of Kubusunan,Yemaquan attributing toI-type granites.The rock of Laoyaquan, Huangyangshan, Sujiquan, Sabei formed within-plate setting,the rock of Kubusunan, Yemaquan, Tasigake formed in islands arc environment. All rocks belonging to the product of collision late post-orogenic extensional stage during late Carboniferous to Permian, the formation environment of each rocks gradually transition from within-plate setting to the island arc environment.5.InTa/Th-Hf/Th-Th/Th chondrite-normalized scheme, all have rock have characteristic of crust-mantle mixing. The magma of Yemaquan,Laoyaquan,Sujiquan is mainlypartial melting;the magma of Kubusunan,Saertielieke,Huangyangshan,Sabei,Tasigakeis mainly fractional crystallization.6.Clarifing uranium concentration of the Permian and Carboniferous granite,discussing the relationship between the genesis of granite and amount of uranium: the amount of uranium of A-type granitesissignificantly higher than I-type granites in the study area,however, these granite rocks is in general depleted uranium.After the last major magmatic activity in Late Carboniferous to Early Permian, the study area is basically in a stable tectonic environment, massive tectonic extension, tectonic hydrothermal activity were not developed,these are not conducive to occuring large-scale hydrothermal uranium mineralization.