Reconstruction of the Paleo‐Ocean Environment Using Mineralogical and Geochemical Analyses of Mixed‐Type Ferromanganese Nodules From the Tabletop of Western Pacific Magellan Seamount

Variations in the geochemistry and mineralogical compositions of ferromanganese (Fe-Mn) nodules are closely related to variations environmental parameters. Therefore, analysis Fe-Mn can reconstruct paleo-ocean environment. Here, three differently shaped were collected from open seamount 9-1 western Pacific Magellan Seamount. Geochemical analyses conducted using micro X-ray fluorescence (μ-XRF) Synchrotron powder diffraction We found that shape was different; however, their geochemical properties similar. For all nodules, μ-XRF elemental distribution revealed a distinct alternation between Mn-rich Fe-rich layers. The layers surrounded nuclei appeared as concentric circles. exhibited low Mn/Fe ratios (<2.5) dominated by vernadite, whereas with high (>2.5) todorokite, respectively. These findings suggest an early diagenesis process at tabletop contents Ca P existence carbonate fluorapatite center indicate formation these began during Miocene phosphatization event (19–16 Ma). In stages nodule formation, diagenetic drove formation. Because global cooling 9 Ma, weakened, after which hydrogenetic became dominant. As result, oxygen minimum zones oxic-suboxic fronts recorded seamount.