Minerals Report - International Seabed Authority

Regarding the formation of the first layer, the bedding revealed at the
base of the section developed during Late Palaeocene – Late Eocene. The ore
matter of this layer has an anthracite-like appearance. The lower half of the
layer contains numerous inter-bedding and intersecting by phosphate veins.
The mineral composition of this layer is a typical association of vernadite,
ferroxigite and apatite. High concentrations of phosphorus and calcium, and
low concentrations of metal components due to their impoverishment by
phosphate materials are typical of its chemical composition.
The second layer, Layer II, is above Layer I, and is distinguished from
this layer by way of a sharp contact. The structure of the ore matter is a
radial-columnar pattern. Large pores between columns are partly filled with
non-ore typical of its mineral composition. A sharp decrease of phosphate
concentrations and high concentrations of metal components are the typical
chemical composition of this bed. Its age is Miocene.
The third layer, Layer III, completes the section. This bed can have
either a gradual or sharp contract with the underlying layer. The bed has a
massive appearance and is of dark brown colour. Its composition is mainly
radial-columnar, although thin-laminated varieties are possible. The major
mineral associated with this layer is vernadite-ferroxigite-quartz. Its chemical
composition is characterized by the maximum concentrations of useful
components, firstly manganese and cobalt, and a high metal content. The age
of the bed is Pliocene-Quaternary.
Often a section of crust is not complete, and is found with missing
layers. In some cases, at the base of the section, there are relicts of ancient
crusts from Late Cretaceous to Late Palaeocene, having significant differences
in structure and composition from the younger ones (Figure 6).
In order to consider the distribution of valuable metal components in
these crusts, it should be noted that these types are mostly concentrated in
crusts of the facies found at gently dipping and sub horizontal surfaces. At
the same time, on slopes in some localities, high concentrations of manganese
and nickel can be observed. Obtaining additional data did not confirm a
relationship of metal distribution with depth, as was the assumption in the
earlier stages of investigation.
INTERNATIONAL SEABED AUTHORITY 172