GEOCHEMICAL CHARACTERISTICS OF VOLCANIC ROCKS FROM TANGBALE OPHIOLITE IN THE WESTERN JUNGGAR OF XINJIANG

GEOCHEMICAL CHARACTERISTICS OF VOLCANIC ROCKS FROM TANGBALE OPHIOLITE IN THE WESTERN JUNGGAR OF XINJIANG 1 first-author Institute of High Energy Physics, Academia Sinica, Beijing 100080, China Institute of High Energy Physics, Academia Sinica, Beijing 100080, China An INAA technique was applied to determine simultaneously abundances of rare-earth, transitional metal, large-ion lithophile and high field strength elements in volcanic rocks from Tangbale ophiolite belt. The detailed study on trace element geochemistry shows that the volcanic rocks were erupted in the back-arc basin. The volcanic rocks of early and middle stages of the expanding period of the basin have low REE and other incompatible element contents. At early and late stages of closing period of the basin, alkalic basalts, basaltic andesites and andesites were erupted in which light REE and other incompatible elements were enriched. INAA Volcanic rocks Geochemical characteristics Tangbale ophiolite Basalt Andesite REFERENCES Yang Ruiying , Huang Zhongxiang , Jiang Yong . Nuclear Techniques (in Chinese) , 1982 , ( 4 ): 36 . Nuclear Techniques (in Chinese) Yang Ruiying , Huang Zhongxiang . Nuclear Techniques (in Chinese) , 1985 , ( 1 ): 29 . Nuclear Techniques (in Chinese) Flanagan J F . Descriptions and analysis of eight new USGS rocks standards . Washington : U.S.Govenment Print Office , 1976 . Descriptions and analysis of eight new USGS rocks standards Thorpe R S , Potts P J , Francis P W . Contrib Mineral Petrol , 1976 , 54 : 65 . Contrib Mineral Petrol Pearce J A . Proceedings of international ophiolite symposium, Cyprus, 1979 . Cyprus : A.Panayiotou , 1980 : 261 - 272 . Pearce J A , Alabaster T , Shelton A W et al . Philos Trans R Soc Lond , 1981 , A300 : 299 . Philos Trans R Soc Lond Wood A D , Toron T L , Treuil M . Earth and Planetary Science Letters , 1979 , 45 : 326 . Earth and Planetary Science Letters 1992-11-01 2021-02-05 1992 Nuclear Science and Techniques 4 3