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Fig. 1. Normalized Mn K x-ray absorption near-edge structure (XANES) spectra of field-moist (oxidized) and reduced West Point (WP) soil (heavy lines), showing the changes in Mn oxidation state after each step of a sequential extraction, and best fits of linear combinations of MnSO4, bixbyite, and birnessite to the raw XANES spectra (thin lines). Fit results equal %MnSO4:%Mn2O3:%birnessite. For comparison, three Mn oxidation state standards (MnSO4, bixbyite, and birnessite) and rhodochrosite (MnCO3) are also plotted.
