Fine‐scale chemostratigraphy of cross‐sectioned hydrogenous ferromanganese nodules from the western North Pacific

A broad area densely covered by ferromanganese nodules was recently discovered around Minamitorishima (Marcus) Island, representing a high-potential metal resource, particularly for Co, Ni, Mo, and W. We studied 16 nodule samples from fields Island. To define the fine-scale chemostratigraphy of nodules, polished cross-sections were analyzed microfocus X-ray fluorescence. Our results show that general pattern compositional variation common throughout growth history in all regions we studied. Chemical mapping clarified changes chemical signature proportion five lithological components history: Mn represented columnar δ-MnO2; Fe layered amorphous FeOOH*xH2O; Ti TiO2*2H2O intergrown with an FeOOH phase; P, Ca Y particles biogenic calcium phosphate; Si, Al, K, Cu, Ni pelagic sediment infills. proposed method creating multi-dimensional map observed oxide layers on basis merging mapped Mn, Fe, Ti, Si Cu intensities. Multi-dimensional sampled western North Pacific revealed two fundamental findings: (1) previously recognized first-order Fe–Mn layers, L0, L1, L2, further divided into two, three, four sublayers, respectively, (2) delayed supply material to be nuclei or hiatus layer(s), leading missing sublayers L0 regulated size. In contrast, layer which does not have any commonly this study has been reported studies other Pacific. propose, therefore, L1 is key facies examining chemostratigraphic correlations areas seafloor.