Discovery of new hydrothermal vent sites in Brans¢eld Strait, Antarctica
We carried out a search for hydrothermal vents in the Central Basin of Bransfield Strait, Antarctica. The ZAPS (zero angle photon spectrometer) chemical sensor and instrument package (Oregon State University), OFOS (ocean-floor observation system) camera sled and TVG (TV-grab) (GEOMAR) were used to...
Main Authors: | , , , , , , , , |
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Other Authors: | |
Format: | Text |
Language: | English |
Published: |
2001
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Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.517.2476 http://www.science.oregonstate.edu/~kellerr/Klinkhammeretal01BSvents.pdf |
Summary: | We carried out a search for hydrothermal vents in the Central Basin of Bransfield Strait, Antarctica. The ZAPS (zero angle photon spectrometer) chemical sensor and instrument package (Oregon State University), OFOS (ocean-floor observation system) camera sled and TVG (TV-grab) (GEOMAR) were used to explore the water column and underlying seafloor. These operations were supplemented with a series of dredges. Hydrothermal plumes over Hook Ridge at the eastern end of the basin are confined to the E ridge crest and SE flank. The plumes are complex and sometimes contain two turbidity maxima one widespread feature centered at 1150 m and a smaller, more localized but broad maximum at 600^800 m. We traced the source of the shallower plume to a sunken crater near the ridge crest using sensors on the ZAPS instrument package. Subsequently two TV-grabs from the crater brought back hot, soupy sediment (42^49‡C) overlain by hard, siliceous crusts and underlain by a thick layer of volcanic ash. We also recovered chimney fragments whose texture and mineralogy indicate venting temperatures in excess of 250‡C. Native sulfur and Fe-sulfides occur in fractures and porous layers in sediment from throughout the area. Pore water data from the crater site are consistent with venting into a thin sediment layer and indicate phase separation of fluids beneath Hook Ridge. The source of the deeper plumes at Hook Ridge has yet to be located. We also explored a series of three parallel volcanic ridges west of Hook Ridge called Three Sisters. We detected water column anomalies indicative of venting with |
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