Pelagic Muds

Kato et al. (2011) found vast amounts of deep sea mud in the Pacific Ocean. The muds are generally metalliferous sediment, zeolitic clay, and pelagic red clay. Thicknesses vary from a few meters to 70 m. They occur up to 50 m below the sea floor. These deposits occur in the eastern South Pacific and central North Pacific. They contain 1000-2300 ppm total REY (REE + Y). In the eastern South Pacific (5°-20° S, 90°-150° W), the REY-rich mud has high REY contents, 1000-2230 ppm total REY and 200 30 ppm total HREE. REY contents of the mud are comparable to or greater than those of the southern China ion-absorption-lype deposits (where EREY = 500-2000 ppm EHREE = 50-200 ppm) notably, the HREEs are in general nearly twice as abundant as in the Chinese deposits (Kato et al. 2011). 

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Nontronite apparently forms under the same general environmental conditions as the low-iron montmorillonites. It is formed by hydrothermal alteration and as vein fillings. It is commonly formed by both the hydrothermal alteration and surface weathering of basalt. Nontronite is the dominant clay in some soils (Ross and Hendricks, 1945). Arrhenius (1963) found that much of the authigenic montmoril-lonite in the pelagic muds of the Pacific Ocean has a relatively high iron content. 

Deep Sea Pacific Ocean Crusts, pelagic muds ... 

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