STUDY ON MAIN FACTORS OF THE CONTROLLING GEOCHEMICAL CHARACTERISTICS OF FERROMANGANESE NODULES (Ⅱ)——FORMATIVE MECHANISM OF DIFFERENT GEOCHEMICAL TYPE NODULES

Based on the study of geochemical characteristics of the different Mn/Fe ferromanganese nodules, the formative mechanism of different geochemical type ferromanganese nodules are discussed in detail by analysing the relationship between different Mn/Fe nodules and their sediments (rock), pore water, overlying water, biological (bacteria) information from the rare earth element geochemistry, sedimentary geochemistry and biogeochemistry. The result shows that the formation mechanism of different Mn/Fe nodules is obviously different, and according to the formative mechanism, the ferromanganese nodules of the South China Sea and the Northern Central Pacific can be classified principally into three geochemical types: volcanic sedimentary mechanism (Mn/Fe≤1.50), oxidation diagenetic mechanism (Mn/Fe>1.50≤2.50) and suboxic organic diagenetic mechanism (Mn/Fe>2.50).