Iron-Manganese Nodules from Nares Abyssal Plain: Geochemistry and Mineralogy

Abstract

Three nodules from a core taken north of Puerto Rico are composed chiefly of an x-ray amorphous, hydrated, iron-manganese oxide, with secondary goethite, and minor detrital silicates incorporated during growth of the nodules. No primary manganese mineral is apparent. The nodules are enriched in iron and depleted in manganese relative to Atlantic Ocean averages. The formation of these nodules appears to have been contemporary with sedimentation and related to volcanic activity.

Study of the spectro‐chemical signatures of cobalt–manganese layered oxides (asbolane–lithiophorite and their intermediates) by Raman spectroscopy

“…They were described in many places around the world, including the oxidized horizon of large ore deposits in New‐Caledonia, Australia, the Democratic Republic of the Congo (DRC), Cameroon amongst others. They also represent phases encountered as Ni–Co enriched manganese nodules of the deep ocean floors …”

“…The composition of the primary rocks from which Ni and Co elements were mobilized and then concentrated into alteration horizons explains this difference in Ni‐content . Asbolane was also described in some ferro‐manganese deep sea nodules, along with buserite, and represent thus also a potential economic interest, trapping Co and Ni along other economic manganese oxides like todorokite.…”