Hydrothermal origin of Late Proterozoic bedded chert at Gusui, Guangdong, China: petrological and geochemical evidence

Authors

  • YONGZHANG ZHOU,

    1. Sciences de la Terre/Centre d'Études sur les Ressources Minérales, Université du Québec à Chicoutimi, Canada
    2. Institute of Geochemistry, Guangzhou Branch, Chinese Academy of Sciences, China
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    • Institute of Geochemistry (Guangzhou Branch), Chinese Academy of Sciences, PO Box 1131, Wushan, Guangzhou, Guangdong Province, China 510640.

  • E. H. CHOWN,

    1. Sciences de la Terre/Centre d'Études sur les Ressources Minérales, Université du Québec à Chicoutimi, Canada
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  • JAYANTA GUHA,

    1. Sciences de la Terre/Centre d'Études sur les Ressources Minérales, Université du Québec à Chicoutimi, Canada
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  • HUANGZHANG LU,

    1. Sciences de la Terre/Centre d'Études sur les Ressources Minérales, Université du Québec à Chicoutimi, Canada
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  • GUANGZHI TU

    1. Institute of Geochemistry, Guangzhou Branch, Chinese Academy of Sciences, China
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ABSTRACT

The Late Proterozoic bedded chert from Gusui in Guangdong Province, southern China, is characterized by bedded, laminated, massive and pseudobrecciated structures. The chert is depleted in TiO2, Al2O3 and most trace elements. However, it is enriched in Ba, As, Sb, Hg, and Se. In Al-Fe-Mn ternary diagrams, it falls into the ‘hydrothermal field’. Factor analysis shows that many elements show up in the principal trace element factor suggesting their enrichment results from leaching of the country rock by hydrothermal solutions. The chert has low REE concentrations and displays an REE pattern consistent with a hydrothermal origin. It may have formed in a Late Proterozoic rift or extension zone developed within the Yunkai continental margin back-arc basin, with a fault system linking it to an unknown heat source at depth.

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