New ocean venting field found in eastern Pacific.
The significance of the discovery, the Commerce Department scientist said, is that the United States now has within its Exclusive Economic Zone "a natural setting providing scientists a new frontier for scientific investigation to study first-hand how seafloor hot springs form metallic mineral deposits, support exotic forms of life, and influence the ocean environment." Rona said, large plates of the earth's crust are pulling apart, allowing seawater to seep through cracks and come in contact with hot volcanic rocks in the area of the find. The heated water leaches metals from the rocks, then rises and deposits the metallic minerals on the sea floor.
Diving to depths of 10,000 feet on the eastern wall of a valley in the submerged volcanic mountain range, the scientists observed diffuse flows of low-temperature fluids seeping up through the sea floor, as well as geyser-like flows of high temperature fluids spewing through chimney-like structures up to 10 feet high. The temperature of the water in one of the hot springs was recorded at nearly 500@F, Rona said. Within the field of hot springs, toppled chimneys resembling fallen logs are strewn about the seafloor. Thickets of tube worms several feet high, topped with bright red plumes, are growing around the springs, and scientists saw crabs, octopi, deep-sea fish, and other animals.
The discovery was made as the party was carrying out geological and biological investigations of the northern Gorda Ridge. The expedition was coordinated by the Gorda Ridge Technical Task Force, a joint Federal-state working group established in 1984 by the secretary of the Department of the Interior and the governors of Oregon and California. Members of the dive team were from NOAA, the U.S. Geological Survey, Oregon State University, the Oregon Department of Geology and Mineral Industries, and the Universities of California (Davis) and Hawaii.
Recognizing the navy's contribution to the study by making the DSV Sea Cliff and its support vessel, the DSVSS Laney Chouest, available, the scientific team has designated the area--situated high above cliffs on the wall of a valley--as the Sea Cliff Hydrothermal Field.
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|Publication:||Marine Fisheries Review|
|Date:||Jan 1, 1989|
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