An off-axis hydrothermal vent field near the Mid-Atlantic Ridge at 30 degrees N

Nature. 2001 Jul 12;412(6843):145-9. doi: 10.1038/35084000.

Abstract

Evidence is growing that hydrothermal venting occurs not only along mid-ocean ridges but also on old regions of the oceanic crust away from spreading centres. Here we report the discovery of an extensive hydrothermal field at 30 degrees N near the eastern intersection of the Mid-Atlantic Ridge and the Atlantis fracture zone. The vent field--named 'Lost City'--is distinctly different from all other known sea-floor hydrothermal fields in that it is located on 1.5-Myr-old crust, nearly 15 km from the spreading axis, and may be driven by the heat of exothermic serpentinization reactions between sea water and mantle rocks. It is located on a dome-like massif and is dominated by steep-sided carbonate chimneys, rather than the sulphide structures typical of 'black smoker' hydrothermal fields. We found that vent fluids are relatively cool (40-75 degrees C) and alkaline (pH 9.0-9.8), supporting dense microbial communities that include anaerobic thermophiles. Because the geological characteristics of the Atlantis massif are similar to numerous areas of old crust along the Mid-Atlantic, Indian and Arctic ridges, these results indicate that a much larger portion of the oceanic crust may support hydrothermal activity and microbial life than previously thought.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Atlantic Ocean
  • Evolution, Chemical
  • Geologic Sediments*
  • Marine Biology
  • Minerals
  • Origin of Life
  • Seawater
  • Temperature
  • Water Microbiology*
  • X-Ray Diffraction

Substances

  • Minerals