| Ore-forming Response to Syndepositional Submarine Volcanism in Langshan-Zhaertai Mesoproterozoic SEDEX Ore Belt, Inner Mongolia, China |
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| 作者姓名： | Peng Runmin Zhai Yusheng Deng Jun Xiao Rongge Wang Jianping Faculty of Earth Sciences and Mineral Resources China University of Geosciences Beijing China |
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| 作者单位： | Peng Runmin Zhai Yusheng Deng Jun Xiao Rongge Wang Jianping Faculty of Earth Sciences and Mineral Resources，China University of Geosciences，Beijing 100083，China |
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| 基金项目： | This study is supported by the State“973”High-Tech Project( No. G19990 43 2 15 ) and the Key Project of the Former Ministry o |
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| 摘 要： | INTRODUCTIONThe L angshan- Zhaertai metallogenic belt is a typicalSEDEX belt of the Mesoproterozoic passive continental m ar-gins in the west section of the northern margin of the NorthChina platform(Zhai et al.,1997) (Fig.1) .The ore- form inggeological setting,the division and correlation of the host suc-cession,the geological features of typical ore deposits andtheir genesis of the belt have been described in references(Zhai et al.,1997;Wang and Zhao,1994;Wang et al.,1992 ;L i et…
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Ore-forming Response to Syndepositional Submarine Volcanism in Langshan-Zhaertai Mesoproterozoic SEDEX Ore Belt, Inner Mongolia, China |
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| Peng Runmin Zhai Yusheng Deng Jun Xiao Rongge Wang Jianping Faculty of Earth Sciences and Mineral Resources,China University of Geosciences,Beijing ,China.Ore-forming Response to Syndepositional Submarine Volcanism in Langshan-Zhaertai Mesoproterozoic SEDEX Ore Belt, Inner Mongolia, China[J].Journal of China University of Geosciences,2000,11(3). |
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| Authors: | Peng Runmin Zhai Yusheng Deng Jun Xiao Rongge Wang Jianping |
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| Abstract: | Ore-forming process of the Dongshengmiao, Huogeqi, Tanyaokou and Jiashengpan deposits in Langshan-Zhaertai Mesoproterozoic SEDEX metallogenic belt is closely related to the syndepositional volcanic activities based on the following facts: (1) The Sm-Nd isochron age of the basic volcanic rocks varies from 1 491 Ma to 1 824 Ma (more than or close to the model age of the lead isotope of all sulfide minerals) in these deposits, with ε(Nd, t) = (3.48-6.40)±0. 80, whose REE composition is enriched in LREE and depleted in HREE, indicating that these volcanic rocks were derived from the mantle or lower crust. (2) The REE composition of some Pb-Zn-Py-ores is also enriched in LREE and depleted in HREE. The chondrite-normalized REE patterns are similar to those of the basic-volcanic rocks. (3) In the lead isotope composition diagram of Doe and Zartman, most of sphalerite, galena, pyrite, pyrrhotite and chalcopyrite are plotted on both sides of the line for the mantle or between the lines for the mantle and lower crust. (4) Cobalt content of some pyrites is much higher than their nickel content (w(Co)/w(Ni)＝11. 91-12. 19). (5) Some volcanic blocks and debrises have been picked out from some pyrite and pyrrhotite ores. (6) All Zn-Pb-Cu-Fe sulfide orebodies in these deposits occur in the strata overlying the metamorphic volcanic rocks in the only second ore-bearing formation. The Jiashengpan deposit lacks in syndepositional volcanic rocks in the host succession, only Pb and Zn occur without Cu, but the Dongshengmiao, Tanyaokou and Huogeqi deposits with syndepositonal volcanic rocks in the host succession contain Cu, indicating the relatively high ore-forming temperatures, besides Pb and Zn. The syndepositional volcanic eruption directly supplied some ore-forming metals and resulted in the secular geothermal anomaly favorable for the circulation of the submarine convective hydrothermal system, and in the precipitation of deep mineralizing fluids exhaling into the anoxide basins along the syndepositional fault system in the Langshan-Zhaertai rift. |
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| Keywords: | volcanic activities ore forming response SEDEX deposit Mesoproterozoic Inner Mongolia |
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