Minerals Report - International Seabed Authority

complete a preliminary evaluation of the entire mid-ocean ridge from the
Bouvet triple junction in the south Atlantic to the Rodrigues triple junction in
the central Indian Ocean, by Spring 2001.
He informed participants of a new international research programme
that has been initiated in the Knipovich Ridge, north of Iceland and
immediately south of Spitsbergen. The venture is a joint Japanese/Russian
research programme with additional participation from US, UK and other
European researchers. He also informed participants of an even more
ambitious programme scheduled to begin in 2001, in which two icebreaker
expeditions are planned using the US icebreaker, Healy and the German
research vessel, Polarstern. This venture, he stated, will investigate
hydrothermal venting along the Gakkel Ridge that extends north of
Spitsbergen directly across the ice-covered Arctic Ocean Basin.
On techniques for locating hydrothermal activity, Dr. German stated
that the most popular method is through integrated geophysical and
geochemical approaches. In this method, multibeam swath bathymetric maps
for navigation are essential. The optimal approach is then to deploy deeptowed
side-scan sonar equipment with in situ real-time continuous optical
backscatter sensors. These instruments would intercept particle-laden “black
smokers” and when such signals are intercepted, detailed geological sidescan
sonar images of the underlying seafloor can be provided. Once a
hydrothermal site has been located, the evaluation of deposits as a resource
potential can be initiated using a tethered or manned deep ocean vehicle.
Submersibles and remotely operated vehicles can be deployed. Dr. German
also pointed out that the limitation to the majority of the current investigative
methods is that they focused primarily on black smoker type hydrothermal
sources, the typical sulphides forming systems throughout the deep Midocean
Ridge of the Area. These sulphides forming systems are inefficient in
terms of the generation of massive sulphides because a substantial proportion
of the metallic minerals that are precipitated are not deposited, and instead
are dispersed widely to the surrounding seafloor by hydrothermal plumes.
He noted that while such plumes cannot be detected using in situ optical
sensors, they can be detected by relying on chemical indicators of dissolved
gases, notably methane.
INTERNATIONAL SEABED AUTHORITY 42