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MRD-02 Deep sources and signatures of ore forming systems - a tool for new discoveries of mineral deposits
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Geological characteristics of sedimentary exhalative deposits and their relationships to hydrothermal sedimentary rocks in western Qinling Mountains Region (China)
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Yongzhang Zhou, Sun Yat-sen (Zhongshan) University (China)
Hongzhong Li, State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (China)
Zhijun Yang, Sun Yat-sen (Zhongshan) University (China)
Junguo He, Sun Yat-sen (Zhongshan) University (China)
Wen Li, Sun Yat-sen (Zhongshan) University (China)
Zhihong Gu, Sun Yat-sen (Zhongshan) University (China)
Wenchao Lu, Sun Yat-sen (Zhongshan) University (China)
Junxing Zhao, Sun Yat-sen (Zhongshan) University (China)
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The Qinling moutains region is a world-famous continental orogen and an important polymetalic minerogenic belt. Lots of ore deposits have been found in the region, Included among them are the Changba-Lijiagou large-scale Pb-Zn deposit and Daxigou-Yingdongzi silver polymetalic deposit. The deposits are hosted in sedimentary carbonate and clastic rocks, and classified to Sedimentary Exhalative Deposits (SEDEX). This paper analyzes the geological and geochemical characteristics of the Changba-Lijiagou Pb-Zn deposit, as well as its ore-forming process in the sedimentary exhalation sytem and the tectonic background and evolution of the western Qinling mountains region.
It is concluded that there are two belts of the sedimentary exhalative deposits in the western Qingling region. They developed from earlier Silurian to middle Devonian. The extensional tectono-environment resulted from the Shangdan subduction zone in the north of Qinling microplate is favorable for the formation of the sedimentary exhalative deposits. In the Changba-Lijiagou Pb-Zn deposit, middle Devonian intermediately metamorphosed clastic rocks and carbonate are its direct host formation. Three kinds of hydrothermal sedimentary rocks, dolomite, albite rock and barite rock, are observed in the Changba-Lijiagou Pb-Zn deposit. The basement with great depth below the basin, the stretched basin and thermal cycle system are the prior factors of SEDEX-type ore deposits.
This study is supported by the 973 Program of China (No. 2006CB4035008; 2002CB412600-V) and NNSFC (No.40573019)
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