Sediment samples from the top of Loihi seamount, southeast of the island of Hawaii, were examined by neutron activation analysis and X-ray fluorescence. The <0.062-mm fraction is reddish x-amorphous iron hydroxide with a low rare-earth-element content similar to chondrite. The >0.062-mm fraction is sand-size grit consisting of olivine, opaque magnetic material, and basaltic glass. The lack of alteration products, such as palagonite or smectite, and the absence of seawater rare-earth-element signature for the amorphous iron hydroxide indicate minimal interaction with seawater. The elemental composition (including the rare-elements) suggests that the combination of the grit and amorphous iron hydroxide is a sedimentary analog of early Archean amphibolite-iron oxide fades.

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