Natural History in Paris (Geistdoerfer) and the University of Udine in Italy
(Spadea).
The purpose of the Naudur cruise was to make detailed observations on the
various segments of the south EPR between 17°S and 19°S and do more extensive
sampling of the hydrothermal fields discovered previously during the Geocyatherm cruise (Fouquet et al. 1996). Indeed, the Geocyatherm cruise spent only
7 days in the area. The major objective of Naudur’s 30 day cruise was to find out
the extent of fresh lava on the domed shaped regions, also called the ‘‘Hump’’ area
by our American colleagues (Cormier et al. 1996), which marks a shallow regional
depth with respect other segments of the EPR.
Between the two cruises (Geocyatherm Leg 1 and Naudur), a total of twentythree dives were made and about 50 hydrothermal sites were visited. The main
observation made during these cruises was that the domed shaped topographic
highs of the different spreading segments visited are topped with fresh lava. New
hydrothermal fields in their early stage of formation were also discovered.
Losing the deep-towed camera system in a lava pond. The name SCAMPI is
an acronym in French for ‘‘Système de CAMera Ponctuel Intéractif’’. The device
is an interactive deep towed camera system that was constructed at IFREMER in
Brest and used during the Geocyatherm cruise (Leg 1) in 1984 on the South East
Pacific Rise between 17°S and 21°S. This deep towed instrument consists of a
metal frame of 2 9 0.8 x 1.2 m in size weighing about 700 k. Large probe lights,
photographic and television cameras are attached on the sled (See Chap. 1).
SCAMPI is towed by an armored coaxial cable, which sends real-time information
to the surface and has a depth capability of 6,000 m. In order to be able to view
and recognize the structures, it has to be at an altitude of less than 5–8 m above the
sea floor. While we were surveying a rough terrain along the axis of the SEPR with
deep towed instruments, an accident happened. Suddenly a blurry signal was
received from the electric conducting wire and the total weight on the cable
dropped down suddenly. It was clear that we had lost the engine. Indeed, when we
rewound the cable, nothing was hanging off the end of it. It was quickly decided
that we should try to recover the instrument using the submersible.
The submersible group was familiar with rescue operations conducted on other
occasions. They had been involved in several recovery operations for airplane
wreckage, missiles and other material lost at sea. In the morning, the group set a
thick rope of about 10 cm in diameter aligned carefully in several rows along the
back deck. The chief of the submersible group, Jean Roux, gave permission to go
ahead and try to recover the lost engine with the Cyana. The total length of the
rope had to be longer than the depth of the ocean floor, that is to say, more than
2600 m in length. The portion of the rope laid on the deck was rolled-up on a
winch, which is used to pull material back up from the depths. The goal was to
deploy the rope down to the seafloor with a transponder that the submarine would
interrogate in order to find it. A hook was attached to the end of the rope, and then
the Cyana was supposed to grasp it and carry to the site of the lost engine so it
could be hooked to the rope. Then the ship would have to pull on the rope. This
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7 Oceanic Spreading Ridges and Sea Floor Creation
(Spadea).
The purpose of the Naudur cruise was to make detailed observations on the
various segments of the south EPR between 17°S and 19°S and do more extensive
sampling of the hydrothermal fields discovered previously during the Geocyatherm cruise (Fouquet et al. 1996). Indeed, the Geocyatherm cruise spent only
7 days in the area. The major objective of Naudur’s 30 day cruise was to find out
the extent of fresh lava on the domed shaped regions, also called the ‘‘Hump’’ area
by our American colleagues (Cormier et al. 1996), which marks a shallow regional
depth with respect other segments of the EPR.
Between the two cruises (Geocyatherm Leg 1 and Naudur), a total of twentythree dives were made and about 50 hydrothermal sites were visited. The main
observation made during these cruises was that the domed shaped topographic
highs of the different spreading segments visited are topped with fresh lava. New
hydrothermal fields in their early stage of formation were also discovered.
Losing the deep-towed camera system in a lava pond. The name SCAMPI is
an acronym in French for ‘‘Système de CAMera Ponctuel Intéractif’’. The device
is an interactive deep towed camera system that was constructed at IFREMER in
Brest and used during the Geocyatherm cruise (Leg 1) in 1984 on the South East
Pacific Rise between 17°S and 21°S. This deep towed instrument consists of a
metal frame of 2 9 0.8 x 1.2 m in size weighing about 700 k. Large probe lights,
photographic and television cameras are attached on the sled (See Chap. 1).
SCAMPI is towed by an armored coaxial cable, which sends real-time information
to the surface and has a depth capability of 6,000 m. In order to be able to view
and recognize the structures, it has to be at an altitude of less than 5–8 m above the
sea floor. While we were surveying a rough terrain along the axis of the SEPR with
deep towed instruments, an accident happened. Suddenly a blurry signal was
received from the electric conducting wire and the total weight on the cable
dropped down suddenly. It was clear that we had lost the engine. Indeed, when we
rewound the cable, nothing was hanging off the end of it. It was quickly decided
that we should try to recover the instrument using the submersible.
The submersible group was familiar with rescue operations conducted on other
occasions. They had been involved in several recovery operations for airplane
wreckage, missiles and other material lost at sea. In the morning, the group set a
thick rope of about 10 cm in diameter aligned carefully in several rows along the
back deck. The chief of the submersible group, Jean Roux, gave permission to go
ahead and try to recover the lost engine with the Cyana. The total length of the
rope had to be longer than the depth of the ocean floor, that is to say, more than
2600 m in length. The portion of the rope laid on the deck was rolled-up on a
winch, which is used to pull material back up from the depths. The goal was to
deploy the rope down to the seafloor with a transponder that the submarine would
interrogate in order to find it. A hook was attached to the end of the rope, and then
the Cyana was supposed to grasp it and carry to the site of the lost engine so it
could be hooked to the rope. Then the ship would have to pull on the rope. This
244
7 Oceanic Spreading Ridges and Sea Floor Creation