Minerals Report - International Seabed Authority

small spreading centres) stated that in the Gulf of California there were no
brine pools. He emphasized that the key to brine pools was salt. He noted
that the hot springs in the Red Sea are more saline than the surrounding
seawater. As a result, instead of the smoke buoyantly rising, it accumulates
the metals into the ponds and makes for a very efficient system for
concentrating the metals.
Asked what happens to massive sulphides deposits when the ocean
floor parts from the axis of the submarine mountain ridge, Professor Rona
provided a number of possibilities as to their fate. One possibility that he said
had been observed was their uplift and incorporation into the conveyor belts
of lava and material on either side of the submerged volcanic range. He also
said that in this process, the massive sulphides deposits are being
decomposed/oxidized on the seafloor. Another possibility he identified was
that they could be covered by sediments and by lava flows and undergo,
chemical changes that could help preserve them. He suggested that such
deposits would be difficult exploration targets because they would be buried.
He also referred to an exploration method that had been developed base don
a magnetic signature that is associated with hot springs.
Another participant stated that in Dr. Rona’s presentation he had said
that there were distinct biological organisms at the massive sulphide mounds
but that their larvae could spread through the sub mid-ocean current. He
wanted to find out if there was a gradient to describe the larvae going from
the mound to other areas. In response, Dr Rona stated that there are different
species at different vents and that the farther away from the vent that one
looked, the greater the differences with the vent communities. He noted that
the eco-system at vents in the Pacific Ocean was dominated by large tubeworms
and giant clams while in the Atlantic, the ecosystem was dominated
by new varieties of shrimp. He referred to the forthcoming presentation by
Dr. Juniper as a better opportunity for a response to this question.
Another participant wanted to know whether or not any of the
geothermal energy associated with hot springs on the ocean floor had been
harnessed. If so, he also wanted to know where. Dr. Rona said that at the
head of the Gulf of Mexico, there is a large geothermal power plant called
Cero Prieto and that northward in the Imperial Valley of Southern California,
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