Ferromanganese Ferromanganese is a ferroalloy with high manganese content (high-carbon ferromanganese can contain as much as 80% Mn by weight). It is made by heating a mixture of the oxides MnO2 and Fe2O3, with carbon (usually as coal and coke) in either a bla ...

nodules form in the

oxidizing Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...

environment of the

abyssal The abyssal zone or abyssopelagic zone is a layer of the pelagic zone of the ocean. "Abyss" derives from the Greek word , meaning bottomless. At depths of , this zone remains in perpetual darkness. It covers 83% of the total area of the ocean an ...

pelagic zone The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...

. They are the result of

ion exchange Ion exchange is a reversible interchange of one kind of ion present in an insoluble solid with another of like charge present in a solution surrounding the solid with the reaction being used especially for softening or making water demineralised, ...

reactions that

precipitate In an aqueous solution, precipitation is the process of transforming a dissolved substance into an insoluble solid from a super-saturated solution. The solid formed is called the precipitate. In case of an inorganic chemical reaction leading ...

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 April 2 ...

components from the water (

sedimentary Sedimentary rocks are types of rock (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ...

) or out of the

interstitial An interstitial space or interstice is a space between structures or objects. In particular, interstitial may refer to: Biology * Interstitial cell tumor * Interstitial cell, any cell that lies between other cells * Interstitial collagenase, ...

water of the

sediments Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand a ...

layers (diagenetic). The composition of Manganese-bearing minerals is dependent on how the nodules are formed; sedimentary nodules, which have a lower Mn²⁺ content than diagenetic, are dominated by Fe- vernadite, Mn-

feroxyhyte Feroxyhyte is an oxide/hydroxide of iron, δ-Fe3+O(OH). Feroxyhyte crystallizes in the hexagonal system. It forms as brown rounded to concretionary masses. Feroxyhyte is opaque, magnetic, has a yellow streak, and has a relative density of 4.2. ...

, and asbolane-

buserite Buserite is a hydrated layered Mn-oxide mineral with nominal chemical formula MnO2.''n''H2O. It was named after Swiss chemist professor W. Buser, who first identified it in 1952 in deep-sea manganese nodules. Buser named it 10 Å manganate beca ...

while diagenetic nodules are dominated by buserite I,

birnessite Birnessite (nominally MnO2.''n''H2O) is a hydrous manganese dioxide mineral with a chemical formula of Na0.7Ca0.3Mn7O14·2.8H2O. It is the main manganese mineral species at the Earth's surface, and commonly occurs as fine-grained, poorly crystall ...

todorokite Todorokite is a rare complex hydrous manganese oxide mineral with the chemical formula . It was named in 1934 for the type locality, the Todoroki mine, Hokkaido, Japan. It belongs to the prismatic class 2/m of the monoclinic crystal system, but ...

, and asbolane-buserite.

References

* {{cite journal, last=Novikov, first=C.V., author2=Murdmaa, I.O., year=2007, title=Ion exchange properties of oceanic ferromanganese nodules and enclosing pelagic sediments, journal=Lithology and Mineral Resources, volume=42, issue=2, pages=137–167, doi=10.1134/S0024490207020034 Oceanography