Minerals Report - International Seabed Authority

nodules in terms of these metals - cobalt, nickel, iron and manganese varies in
different parts of the oceans, in relation to their proximity to hot springs and
other factors. The Clarion-Clipperton zone has highest enrichment in the
eastern equatorial Pacific. Then going out from here, the manganese nodules
in the deep abyssal plains of the ocean basins, there are manganese crusts that
accumulate on bare rock volcanic surfaces both on the submerged volcanic
mountain range and on sea mounds and these are the cobalt rich ferromanganese
crusts. These accumulate in water depths roughly between 400
and 4000 metres, and accumulate to thickness up to some tens of centimetres.
With regard to seafloor polymetallic massive sulphides, Professor
Rona pointed out that unlike polymetallic nodules that occurred as a layered
deposit, seafloor polymetallic nodules were three-dimensional deposits with a
depth element that had to be taken into account in resource assessment. The
next step now was to determine the third dimension, the sub sea floor. This
was done in 1994 with an offshore oil drilling ship modified for drilling in the
deep ocean, called the Joides Resolution. A consortium of 20 countries
working together on the ocean drilling programme supported the
programme. The drilling established that that it takes thousands to tens of
thousands of years to form a sizable massive sulphide deposit. Massive
sulphide deposits are not renewable resources. It has been contended that
active seafloor massive sulphides are renewable resources that will regenerate
by precipitation from hot springs almost as quickly as the sulphides are
removed. This may be true only for individual active mineralised chimneys
that have been observed to regenerate within days to years after removal. The
drilling also gave geologists an opportunity to observe volcanogenic massive
sulphide (VMS) deposits in process of formation. Hitherto VMS deposits were
mined in land for centuries for iron, copper, zinc, silver and gold without
understanding how they were formed.
Lastly, Professor Rona touched upon the environmental considerations
and the huge marine biodiversity teeming with millions of species.
Investigations revealed that new species are found in every square metre of
sediments sampled. Sediments look barren but it is actually full of life. With
reference to the deep sea hot springs themselves, every hydrothermal field
examined to date has some species that are not found in any other field.
Marine organisms and microbes are associated with marine mineral deposits
INTERNATIONAL SEABED AUTHORITY 22