Jean-Louis Cheminée, Nivaggioli and Normand. They discovered another
hydrothermal field near 13847
0 N-103856
0 W at 2629 m depth and they called this
area the ‘‘Bryce Canyon’’ site since it reminded Jean-Louis of the landscape at a
place with this name in Utah (USA). This hydrothermal site, like the ‘‘Chain site’’,
was built at the western edge of a lava pond along a fissure oriented N165°. Active
and dead hydrothermal mounds overlaid by chimneys reaching 15–20 m high were
observed. One of them was a very active chimney with three orifices spewing
black fluids at the foot of the tall mound. Temperature probes gave a value of
283 °C in the most active and taller edifice, while a reading of 330 °C was
obtained on a smaller and thinner 10 cm wide chimney.
After the dive we had a briefing, where we were able to watch the videocassette
and hear a description of the dive by Jean-Louis. We decided to make our last dive
on the same site in order to collect samples of hydrothermal fluid and hydrothermal
sediment precipitated on the surroundings near the edifice. It was decided that
Marty, a fluid chemist from IPG, was going to make the last dive with the pilots Guy
Sciarrone and J-M Nivaggioli. On February 26, 1982 Cyana was launched from the
support ship at 9h15 and at 9h24 the submersible was diving. At 10h29, the divers
reached the sea floor near the sample storage basket moored on the sea floor. It took
only about 35 min between their landing and the first bottle sampling. The submarine left the bottom at 16h26 terminating the last dive in the area.
After the submersible was on board, the navigation team started to call back the
three transponders that we had left on the bottom, which it took until one o’clock
in the morning. Soon after we had caught all three transponders, we left the site on
February 27, to transit towards Manzanillo, Mexico. The night of the 27–28th
Vincent Renard, Echardour, Jean-Luc Charlou, Jean-Louis Cheminée, Francis
Albarede and Jean Francois Minster took turns on watch. We arrived in Manzanillo in the afternoon of February 28. The cruise was over and everybody was
pleased with the results. All of us were eager to return to our labs to make detailed
analyses on all the samples we had collected.
After the Searise (1980), Clipperton (1981) and Cyatherm (1982) cruises, a
fourth scientific expedition called ‘‘Geocyarise’’ took place. This project had 3 Legs
on the EPR at 13°N and took place in 1984 with the submersible Nautile and the
support ship N.O. LE NADIR. The first and third Legs of the cruise were devoted to
performing morphological and structural observations and sampling. The second
leg was dedicated to a geochemical approach for studying the water chemistry of
the hydrothermal vents. I participated on leg 1 and was the chief scientist on Leg 3.
Geocyrise Leg 3 began in Manzanillo on February 18, 1984, at 8:00 AM and
returned to Manzanillo on March 5. We left Manzanillo at a speed of about 9 kn
but we had to slow down our speed in order to let the electric conducting cable out.
This cable was important for the geo-electrical experiment that Felix Avedik,
geophysicist, wanted to perform during the cruise. Indeed, we had to verify the
state of the cable before we arrived on the site, and the only way to do it was to lay
out the cable at sea and verify if the electrical connections for the experiment were
operational. Felix and an electronic engineer, Perron, verified the damaged cable
and fixed the portions that were defective. In the morning at 7:30, after working all
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7 Oceanic Spreading Ridges and Sea Floor Creation
hydrothermal field near 13847
0 N-103856
0 W at 2629 m depth and they called this
area the ‘‘Bryce Canyon’’ site since it reminded Jean-Louis of the landscape at a
place with this name in Utah (USA). This hydrothermal site, like the ‘‘Chain site’’,
was built at the western edge of a lava pond along a fissure oriented N165°. Active
and dead hydrothermal mounds overlaid by chimneys reaching 15–20 m high were
observed. One of them was a very active chimney with three orifices spewing
black fluids at the foot of the tall mound. Temperature probes gave a value of
283 °C in the most active and taller edifice, while a reading of 330 °C was
obtained on a smaller and thinner 10 cm wide chimney.
After the dive we had a briefing, where we were able to watch the videocassette
and hear a description of the dive by Jean-Louis. We decided to make our last dive
on the same site in order to collect samples of hydrothermal fluid and hydrothermal
sediment precipitated on the surroundings near the edifice. It was decided that
Marty, a fluid chemist from IPG, was going to make the last dive with the pilots Guy
Sciarrone and J-M Nivaggioli. On February 26, 1982 Cyana was launched from the
support ship at 9h15 and at 9h24 the submersible was diving. At 10h29, the divers
reached the sea floor near the sample storage basket moored on the sea floor. It took
only about 35 min between their landing and the first bottle sampling. The submarine left the bottom at 16h26 terminating the last dive in the area.
After the submersible was on board, the navigation team started to call back the
three transponders that we had left on the bottom, which it took until one o’clock
in the morning. Soon after we had caught all three transponders, we left the site on
February 27, to transit towards Manzanillo, Mexico. The night of the 27–28th
Vincent Renard, Echardour, Jean-Luc Charlou, Jean-Louis Cheminée, Francis
Albarede and Jean Francois Minster took turns on watch. We arrived in Manzanillo in the afternoon of February 28. The cruise was over and everybody was
pleased with the results. All of us were eager to return to our labs to make detailed
analyses on all the samples we had collected.
After the Searise (1980), Clipperton (1981) and Cyatherm (1982) cruises, a
fourth scientific expedition called ‘‘Geocyarise’’ took place. This project had 3 Legs
on the EPR at 13°N and took place in 1984 with the submersible Nautile and the
support ship N.O. LE NADIR. The first and third Legs of the cruise were devoted to
performing morphological and structural observations and sampling. The second
leg was dedicated to a geochemical approach for studying the water chemistry of
the hydrothermal vents. I participated on leg 1 and was the chief scientist on Leg 3.
Geocyrise Leg 3 began in Manzanillo on February 18, 1984, at 8:00 AM and
returned to Manzanillo on March 5. We left Manzanillo at a speed of about 9 kn
but we had to slow down our speed in order to let the electric conducting cable out.
This cable was important for the geo-electrical experiment that Felix Avedik,
geophysicist, wanted to perform during the cruise. Indeed, we had to verify the
state of the cable before we arrived on the site, and the only way to do it was to lay
out the cable at sea and verify if the electrical connections for the experiment were
operational. Felix and an electronic engineer, Perron, verified the damaged cable
and fixed the portions that were defective. In the morning at 7:30, after working all
222
7 Oceanic Spreading Ridges and Sea Floor Creation