Black smokers on the Mid‐Atlantic Ridge

Evidence for a variety of active hydrothermal venting phenomena, including black smokers, was discovered at a site on the Mid‐Atlantic Ridge by a research team of government and university scientists. The work was accomplished on a cruise of the National Oceanic and Atmospheric Administration (NOAA) ship Researcher during July 1985 as part of the NOAA Vents Program. The site of the venting phenomena is the Trans‐Atlantic Geotraverse (TAG) Hydrothermal Field on the east wall of the rift valley of the Mid‐Atlantic Ridge at 26°N. The TAG Hydrothermal Field was the first hydrothermal field to be found on an oceanic ridge; it was discovered 12 years ago in 1973. However, until the present cruise, only low‐temperature hydrothermal activity had been documented, and the existence of higher‐temperature hydrothermal activity along slow spreading oceanic ridges (half rate 2 cm/yr), such as the Mid‐Atlantic Ridge, was in question.