Minerals Report - International Seabed Authority

deep seafloor. Another tool used was to determine if there were elevated
levels of metal particles in the normal deep-sea sediments. Thus is because
the metal particles coming out of the black smokers would also be carried out
by the currents over great distances and would settle on the deep-sea
sediments. By following concentration gradients of these metals in the water
column and in the sediments on the seafloor, Professor Rona stated that his
team felt that it would progressively get close to the possible source of these
materials.
Using slides, Professor Rona took participants on a tour of the
exploration work that was conducted. There were images of the dives by the
submersible Alvin, the production of bathymetric contour maps using satellite
navigation, discovery of the target deposit, photographs of the deposit,
sampling of the deposit, identification of new life forms and drilling the
deposit to enable its volume to be determined.
With regard to some of the technologies used, Dr. Rona presented
participants with images of, inter alia, the water sampling bottle used to
ascertain if there were elevated levels of certain metals in the water column, a
sediment core showing dark layers of sediment containing enriched metals in
the sediment, the echo sounder(s) used to determine the depth and shape of
the seafloor, how satellite navigation is used to give positioned accuracy and
how instruments aboard the Alvin submersible were used to make various
measurements like temperature, to sample and to drill the deposit.
Professor Rona presented some slides of the TAG hydrothermal field
showing the broad array of biodiversity that is to be found in association with
the massive sulphides deposit. Starting in normal seafloor around the
mound, lava flowed normally and deep sea sediments were shown looking
very much like a desert. Suddenly, the colour oasis of the mound came into
view, followed by the hot springs themselves. There were bright green rocks
(massive sulphides) and different types of fish. There were also chimneys up
to several metres high that are no longer active. Closer to the mound were
dome shaped chimneys, several metres high that were discharging blue-white
smoke. These are the white smokers made up primarily of iron sulphides
(pyrite). Professor Rona informed participants that because these dome
shaped chimneys reminded his team of the domes on Old Russian churches
INTERNATIONAL SEABED AUTHORITY 101