Advertisement

Gorda Ridge pp 21-29 | Cite as

Hydrography and Geochemistry of Northern Gorda Ridge

  • Robert W. Collier
  • Edward T. Baker
Conference paper

Abstract

The physics and chemistry of the near-bottom water column above Gorda Ridge were studied for indications of hydrothermal venting. Based on initial sea-floor surveys, three field programs focused on Northern Gorda Ridge, using state-of-the-art shipboard and in situ determinations of physical, optical, and chemical properties useful in “prospecting” for active venting. The results of these investigations demonstrate the presence of active venting in at least two regions of the northernmost ridge segment—the “Narrowgate” section (GR14), and the east slope of the axial valley near its intersection with Blanco Fracture Zone (GR15). Distinct temperature anomalies (≈30 millidegree C) and suspended particle “plumes” were found at both locations during two separate expeditions in 1985. These plumes had stabilized at depths between 2450 and 2900 m and were separated from the bottom by at least 200 m. Detailed sections through the plume at GR14 demonstrated dimensions of at least 2 km (east-west) and 2 to 4 km (north-south), centered over the east wall of the axial valley. The plumes at GR14 and GR15 were not physically connected along the ridge axis. Chemical anomalies in the plumes included high concentrations of dissolved manganese, helium-3, radon-222, and iron-rich hydrothermal precipitates. The composition and hydrography of the plumes suggest that they originated from high-temperature vents. A brief reoccupation of the GR14 site in 1986 failed to relocate these strong plume features.

Keywords

Temperature Anomaly Ridge Axis East Wall Hydrothermal Plume Fuca Ridge 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Baker ET, Massoth GJ, Collier RW, et al. (1987) Evidence for high-temperature hydrothermal venting on the Gorda Ridge, northeast Pacific Ocean. Deep-Sea Res 34: 1461–1476.CrossRefGoogle Scholar
  2. Clague D, Friesen W, Quinterno P, et al. (1984) Preliminary geological, geophysical, and biological data from the Gorda Ridge. USGS Open-File Report 84–364, 49 pp.Google Scholar
  3. Clarke WB, Beg MA, Craig H (1969) Excess helium-3 in the sea: Evidence for terrestrial primordial helium. Earth Planetary Sci Lett 6: 213–220.CrossRefGoogle Scholar
  4. Collier RW, Holbrook SH, Robbins JM (1986) Studies of trace metals and active hydrothermal venting on the Gorda Ridge. State of Oregon, Department of Geology and Mineral Industries Open-File Report 0–86–13, 36 pp.Google Scholar
  5. Cowen JP, Massoth GJ, Baker ET (1986) Bacterial scavenging of Mn and Fe in a mid- to far-field hydrothermal plume. Nature 322: 169–171.CrossRefGoogle Scholar
  6. Dymond J, Corliss JB, Heath GR, Field CW, Dasch EJ, Veeh HH (1973) Origin of metalliferous sediments from the Pacific Ocean. Geol Soc Am Bull 84:3355–3372.CrossRefGoogle Scholar
  7. Edmond JM, Measures C, McDuff RE et al. (1979) Ridge crest hydrothermal activity and the balances of the major and minor elements in the ocean: The Galapagos Data. Earth Planetary Sci Lett 46: 1–18.CrossRefGoogle Scholar
  8. Grassle JF (1986) The ecology of deep-sea hydrothermal vent commonities. Adv Marine Biol 23: 301–362.CrossRefGoogle Scholar
  9. Hickey B (1986) The California Current System-hypotheses and facts. Prog Oceanogr 8: 191–279.CrossRefGoogle Scholar
  10. Kadko D, Lupton JE, Collier R, Lilley MD, Pak H (1986) Endeavour Ridge hydrothermal plume study. EOS 67: 974 (abstract).Google Scholar
  11. Lyle M, Leinen M, Owen RM, Rea DK (1987) Late tertiary history of hydrothermal deposition at the East Pacific Rise, 19°S′: Correlation to volcano-tectonic events. Geophys Res Lett 14: 595–598.CrossRefGoogle Scholar
  12. Malahoff A (1985) Hydrothermal vents and polymetalic sulfides of the Galapagos and Gorda/Juan de Fuca Ridge systems and of submarine volcanos. Biol Soci Wash Bull 6: 19–41.Google Scholar
  13. Middleton JM, Thompson RE (1986) Modeling the rise of hydrothermal plumes. Can Tech Rep Hydrogr Ocean Sci 69, 18 pp.Google Scholar
  14. Riddihough RP (1980) Gorda plate motions from magnetic anomaly analysis. Earth Planetary Sci Lett 51: 163–170.CrossRefGoogle Scholar
  15. Rona PA, Klinkhammer G, Nelsen TA, Trefry JH, Elderfield H (1986) Black smokers, massive sulfides and vent biota at the Mid-Atlantic Ridge. Nature 321: 33–37.CrossRefGoogle Scholar
  16. Speiss FN, Macdonald KC, Atwater T, et al. (1980) East Pacific Rise: Hot springs and geophysical experiments. Science 207: 1421–1433.CrossRefGoogle Scholar
  17. Stommel H (1982) Is the South Pacific helium-3 plume dynamically active? Earth Planetary Sci Lett 61: 63–67.CrossRefGoogle Scholar
  18. Von Damm KL, Bischoff JL (1987) Chemistry of hydrothermal solutions from the southern Juan de Fuca Ridge. J Geophys Res 92: 11,334–11,346.Google Scholar

Copyright information

© Springer-Verlag New York Inc. 1990

Authors and Affiliations

  • Robert W. Collier
  • Edward T. Baker

There are no affiliations available

Personalised recommendations