Carbonate-hosted manganese deposits and ocean anoxia

Late Devonian (ca. 360 Ma), Early Carboniferous (ca. 330 Ma), and Early Triassic (ca. 250 Ma) manganese deposits in the South China Block support an emerging view that some Mn carbonates form through direct synsedimentary (authigenic) precipitation. These Mn carbonates accumulated on distal shelves...

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Veröffentlicht in:Earth and planetary science letters 2023-11, Vol.622, p.118385, Article 118385
Hauptverfasser: Chen, Fangge, Wang, Qingfei, Pufahl, Peir K., Matheson, Edward J., Xian, Haiyang, Nan, Jingbo, Ma, Huan, Deng, Jun
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Sprache:eng
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Zusammenfassung:Late Devonian (ca. 360 Ma), Early Carboniferous (ca. 330 Ma), and Early Triassic (ca. 250 Ma) manganese deposits in the South China Block support an emerging view that some Mn carbonates form through direct synsedimentary (authigenic) precipitation. These Mn carbonates accumulated on distal shelves and are interbedded with lime mudstone and heterozoan carbonates that accumulated in coastal upwelling environments. Lithofacies, Ce anomalies combined with vanadium, uranium, and molybdenum enrichments indicate that the Mn carbonates were primarily precipitated under anoxic conditions. We provide a robust dataset to clarify the precipitation pathway of these Mn carbonates and explore the implications of using them as proxies of regional shallow water and deep-ocean anoxia. In the studied deposits, Mn calcite encases dolomite rhombs (
ISSN:0012-821X
1385-013X
DOI:10.1016/j.epsl.2023.118385