Minerals Report - International Seabed Authority

The global data of both abundance and composition are compiled
on a 1° latitude and longitude grid. Interpolation of data between sampled
localities is based on a minimum surface tension routine (Smith and
Wessel, 1990). This method has the advantage of adjusting value gradients
locally according to the actual sample values, their location and frequency
of occurrence. Interpolation is not believed to give meaningful results
beyond 10° ranges from known localities and, therefore, the data grids do
not extend beyond that limit.
Where abundance, density and compositional data are absent, the
likelihood of occurrence of specific resource types have had to be
estimated from predictive models. These models use knowledge of the
presence or absence of conditions favourable for resource formation to
establish often non-unique predictions of likely occurrence. This method is
especially applicable for gas hydrates and conventional hydrocarbon
resources, although the latter are also described with reference to adjacent
known reserves and estimated resources.
Finally, a value is placed on the resources at current (June 2000)
commodity prices. These estimates are valid only as far as they describe
the total abundance and hence value of the resource in question. They do
not include any recovery, treatment or other production costs that would
be incurred but which, at present, are unknown. A state-by-state summary
of the non-living resources within ELCS areas is given in appendix 1.
4 Non-Living Resources on the Seafloor: Their Formation, Occurrence
and Magnitude
4.1 Marine Placer deposits
4.1.1 What marine placer deposits comprise
Marine placers are detrital heavy metallic minerals which have
become separated from their normally associated light minerals, and can
form in economic concentrations. The most economically important of
these minerals are: cassiterite (tin), ilmenite (titanium), rutile (titanium),
zircon (zirconium), chromite (chromium), monazite (thorium), magnetite
(iron), gold and diamonds (Harben and Bates, 1990).
INTERNATIONAL SEABED AUTHORITY 683