environment, it would rise again to the surface. This phenomenon of water’s
descent and subsequent ascent would take place because of density differences
between the denser cold seawater and the lighter, warmer hydrothermal fluid.
Discovery of Hydrothermal Deposits
Hydrothermal metallic deposits forming iron sulfides and oxides containing significant base metals were first recovered from the Atlantis II Deep in the Red Sea
in 1968–1969 (Degens and Ross 1969). However, the first hydrothermal site to be
directly observed was found during the FAMOUS project in 1974. Scientists
observed and sampled chunks of dark-brown colored hardened crust from a mound
located at the intersection between the transform fault wall and the Mid Atlantic
ridge axis near 36°56
0 40
00 N-33°03
0 40
00 W at 2700 m deep. These chunks were
picked up by the remote controlled arm of the submersible Cyana and placed in the
sampling basket on the front. When the submersible returned to the sea’s surface,
divers brought the sampled material on board the ship. Using just my eyes and my
fingers, I realized that this friable, brown colored material was most likely an ironmanganese compound, probably of hydrothermal origin. I later identified the
samples as being a hydrothermal Fe–Mn oxyhydroxide crust after examining the
material under a microscope and doing some chemical analyses.
Never before seen deep-water organisms colonizing hot springs, better known
as ‘‘hydrothermal vents’’, were first discovered during exploration with a deeptowed camera (called ANGUS) from WHOI (Woods Hole Oceanographic Institution) in the rift valley of the Cocos-Nazca spreading ridge near 85°–87°W and
0°47
0 N in the Pacific Ocean, near the Galapagos Islands. Subsequently, in February–March 1977, during the submersible Alvin’s dives in the same area,
observers saw a luxuriant ‘‘oasis’’ of life around hydrothermal vents (Corliss et al.
1978, 1979). A year later, the French-US team discovered more animal life on the
first polymetallic sulfide deposits found along a segment of a fast spreading ridge
of the East Pacific Rise near 21°N, during the second half of the RITA (anachronism for RIvera-TAmayo) project.
The first part of the RITA project took place in 1978 with the French diving
saucer Cyana and its support ship Le NADIR and was called ‘‘Cyamex’’ (CYanaMEXico). This leg was organized and conducted by a team from CNEXO directed
by Jean Francheteau (Francheteau et al. 1980). Hydrothermal geysers called
‘‘black smokers’’ were observed and described as fountains or strong jets of
mineral-laden water spewing from hydrothermal chimneys several meters tall. In
1979, the RITA project continued with dives using the WHOI submersible Alvin
and its support ship Lulu. At this time, scientists determined that the ‘‘smokers’’
were belching out a homogeneous solution of high temperature (350 °C) fluid
since a temperature probe could measure the black water’s heat at the mouth of the
chimney.
Missing Heat
147
descent and subsequent ascent would take place because of density differences
between the denser cold seawater and the lighter, warmer hydrothermal fluid.
Discovery of Hydrothermal Deposits
Hydrothermal metallic deposits forming iron sulfides and oxides containing significant base metals were first recovered from the Atlantis II Deep in the Red Sea
in 1968–1969 (Degens and Ross 1969). However, the first hydrothermal site to be
directly observed was found during the FAMOUS project in 1974. Scientists
observed and sampled chunks of dark-brown colored hardened crust from a mound
located at the intersection between the transform fault wall and the Mid Atlantic
ridge axis near 36°56
0 40
00 N-33°03
0 40
00 W at 2700 m deep. These chunks were
picked up by the remote controlled arm of the submersible Cyana and placed in the
sampling basket on the front. When the submersible returned to the sea’s surface,
divers brought the sampled material on board the ship. Using just my eyes and my
fingers, I realized that this friable, brown colored material was most likely an ironmanganese compound, probably of hydrothermal origin. I later identified the
samples as being a hydrothermal Fe–Mn oxyhydroxide crust after examining the
material under a microscope and doing some chemical analyses.
Never before seen deep-water organisms colonizing hot springs, better known
as ‘‘hydrothermal vents’’, were first discovered during exploration with a deeptowed camera (called ANGUS) from WHOI (Woods Hole Oceanographic Institution) in the rift valley of the Cocos-Nazca spreading ridge near 85°–87°W and
0°47
0 N in the Pacific Ocean, near the Galapagos Islands. Subsequently, in February–March 1977, during the submersible Alvin’s dives in the same area,
observers saw a luxuriant ‘‘oasis’’ of life around hydrothermal vents (Corliss et al.
1978, 1979). A year later, the French-US team discovered more animal life on the
first polymetallic sulfide deposits found along a segment of a fast spreading ridge
of the East Pacific Rise near 21°N, during the second half of the RITA (anachronism for RIvera-TAmayo) project.
The first part of the RITA project took place in 1978 with the French diving
saucer Cyana and its support ship Le NADIR and was called ‘‘Cyamex’’ (CYanaMEXico). This leg was organized and conducted by a team from CNEXO directed
by Jean Francheteau (Francheteau et al. 1980). Hydrothermal geysers called
‘‘black smokers’’ were observed and described as fountains or strong jets of
mineral-laden water spewing from hydrothermal chimneys several meters tall. In
1979, the RITA project continued with dives using the WHOI submersible Alvin
and its support ship Lulu. At this time, scientists determined that the ‘‘smokers’’
were belching out a homogeneous solution of high temperature (350 °C) fluid
since a temperature probe could measure the black water’s heat at the mouth of the
chimney.
Missing Heat
147