Journal of Marine Sciences ›› 2017, Vol. 35 ›› Issue (4): 76-86.DOI: 10.3969/j.issn.1001-909X.2017.04.008

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Genesis and grade control factors of polymetallic nodules in the East Mariana Basin of Pacific

CAO De-kai1,2, REN Xiang-wen*1,2,3, SHI Xue-fa1,2   

  1. 1. First Institute of Oceanography, SOA, Qingdao 266061, China;
    2. Key Laboratory of Marine Sedimentology & Environmental Geology, SOA, Qingdao 266061, China;
    3. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
  • Received:2017-05-21 Revised:2017-06-13 Published:2022-11-21

Abstract: Geochemical and mineralogical analysis was carried out by ICP-OES, ICP-MS and XRD for the polymetallic nodules collected from the East Mariana Basin and western portions of the China Contract Zone. The genesis and grade control factors of main economic elements in the nodules from the East Mariana Basin were explored. The results show that the nodules are mainly hydrogenetic type in major and ∑REYs elements concentrations and to some extent, their mineral compositions are influenced by diagenetic processing. The contents of Fe, Co, P and other main elements and ∑REYs in the upper surface layer of nodules are higher than those in the lower surface layer, while the contents of Mn, Cu and Ni are significantly higher in the lower surface layer. Based on the characteristics of mineralogy and marine environment as well as the statistical analysis data in this research and other literatures, it can be concluded that the grades of Mn, Ni, Cu, Co, Fe and Ce of nodules from East Mariana Basin are mainly controlled by Mn mineral and the dissolved oxygen of bottom currents as well as the primary productivity of surface seawater, while the grades of La, Y and other rare earth elements are also subjected to the hydrothermal activities from East Pacific Rise.

Key words: polymetallic nodules, surface layer analysis, rare earth elements, control factors

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