WANG Teng1,3, ZHANG Zhen-liang2, YANG Zheng-xi3, BAN Jianyong3, GAO Yong-wei2
(1. Sichuan Xinye Investment Corporation of Mining & Exploration, Chengdu 610059, China;
2. Mineral and Resourance Department of Xi’an Center of Geology Survey, Xi’an 710054, China;
3. Institute of Earth Science, Chengdu University of Technology, Chengdu 610059, China)

Abstract：Beizhan Iron Deposit occurring in Western Tianshan Mountain, were hosted primarily by late Carboniferous volcanic rocks, which mainly contain basalt, basaltic tuff, andesitic tuff, andesite and dacite, were part of high-K calc-alkaline and calc-alkaline. In this paper, representative samples of volcanic rocks from Beizhan Iiron Deposit were analyzed for major and trace elements to validate their tectonic setting. Geochemical data indicate that volcanic rocks show characteristics of light rare earth elements (LREE) enrichment and heavy rare earth elements (HREE) deficit, with the “Left steep right slow”, relative enrichment large iron lithophile element (LILE; e.g., Ba, Rb, Th and U), and negative high field-strength element (HFSE; e.g., Ta, Nb, Y and Hf) as well as highly LREE/HREE(average 5.2),similarly with the features of continental margin arc volcanic rocks. In the plots of tectonic discrimination, the basaltic volcanic rocks are mainly projected in arc volcanic setting regions, and show the trend of evolution of enriched mantle origin region. Combined with the regional geological data, it is clear that the volcanic rocks of mine were the products of continental margin arc setting during the South-Tianshan Ocean toward north beneath the Yili-Centrel Tianshan Plate in the late stage of subduction.
Keywords: Beizhan iron deposit; geochemistry; volcanic rocks; tectonic setting; Western Tianshan

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ACTA MINERALOGICA SINICA Vol. 35, No. 3, 2015, Page 351-358