Advertisement

Marine Geophysical Researches

, Volume 9, Issue 3, pp 211–236 | Cite as

The distribution of geothermal fields along the East Pacific Rise from 13°10′ N to 8°20′ N: Implications for deep seated origins

  • Kathleen Crane
  • Frank AikmanIII
  • Jean-Paul Foucher
Article

Abstract

In 1983 a combined SeaMARC I, Sea Beam swath mapping expedition traversed the East Pacific Rise from 13°20′ N to 9°50′ N, including most of the Clipperton Transform Fault at 10°15′ N, and a chain of seamounts at 9°50′ N which runs obliquely to both the ridge axis and transform fault trends. We collected temperature, salinity and magnetic data along the same track. These data, combined with Deep-Tow data and French hydrocasts, are used to construct a thermal section of the rise axis from 13°10′ N to 8°20′ N.

Thermal data collected out to 25 km from the rise axis and along the Clipperton Transform Fault indicate that temperatures above the rise axis are uniformly warmer by 0.065°C than bottom water temperatures at equal depths off the axis. The rise axis thermal structure is punctuated by four distinct thermal fields with an average spacing of 155 km. All four of these fields are located on morphologic highs. Three fields are characterized by lenses of warmed water ≈ 20 km in length and ≈ 300 m thick. Additional clues to hydrothermal activity are provided in two cases by high concentrations of CH4, dissolved Mn and 3He in the water column and in another case by concentrations of benthic animals commonly associated with hydrothermal regions.

We use three methods to estimate large-scale heat loss. Heat flow estimates range from 1250 MW to 5600 MW for one thermal field 25 km in length. Total convective heat loss for the four major fields is estimated to lie between 2100 MW and 9450 MW. If we add the amount of heat it takes to warm the rest of the rise axis (489 km in length) by 0.065.°C, then the calculated axial heat loss is from 12,275 to 38,525 MW (19–61% of the total heat theoretically emitted from crust between 0 and 1 m.y. in age).

Keywords

East Pacific Rise heat flow diapirism 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Armi, L., 1978, Mixing in the Deep Ocean. The Importance of Boundaries, Oceanus 21, 14–19.Google Scholar
  2. Armi, L. and Millard, R. C.Jr., 1976, The Bottom Boundary Layer of the Deep Ocean, J. Geophys. Res. 81, 4983–4920.Google Scholar
  3. Baines, W. D. and Turner, J. S., 1969, Turbulent Buoyant Convection from a Source in a Confined Region, J. Fluid Mech. 57, 51–80.Google Scholar
  4. Baker, E. T. and Massoth, G. J., 1986a, Hydrothermal Plume Measurements: A Regional Perspective, Science 234, 980–982.Google Scholar
  5. Baker, E. T. and Massoth, G. J., 1986b, The Along-strike Distribution of Hydrothermal Activity on a Spreading Segment of the Juan de Fuca Ridge (abst.), EOS 67, 1027.Google Scholar
  6. Ballard, R. D., Francheteau, J., Juteau, T., Rangin, C., and Normark, W., 1981, East Pacific Rise at 21° N: the Volcanic, Tectonic, and Hydrothermal Processes of the Central Axis, Earth Planet. Sci. Lett. 55, 1–10.Google Scholar
  7. Ballard, R. D. and Francheteau, J., 1982, The Relationship Between Active Sulfide Deposition and the Axial Processes of the Mid-ocean Ridge, Marine Tech. Soc. J. 16, 8–22.Google Scholar
  8. Cann, J. R. and Strens, M. R., 1982, Black Smokers Fuelled by Freezing Magma, Nature 298, 147–149.Google Scholar
  9. Corliss, J. B., Dymond, J., Gordon, L. I., Edmond, J. M., von Herzen, R. P., Ballard, R. D., Green, K., Williams, D., Bainbridge, A., Crane, K., and van Andel, T. H., 1979, Submarine Thermal Springs on the Galapagos Rift, Science 203, 1073–1083.Google Scholar
  10. Crane, K. and Normark, W. R., 1977, Hydrothermal Activity and Crestal Structure of the East Pacific Rise at 21° N, J. of Geophys. Res. 82, B3, 5336–5348.Google Scholar
  11. Crane, K. 1977, Hydrothermal Activity and Near Axis Structure at Mid-ocean Spreading Centers, PhD thesis, Univ. of Calif., San Diego.Google Scholar
  12. Crane, K. and R. D.Ballard, 1980, The Galapagos Rift at 86° W: Structure and Morphology of Hydrothermal Fields, J. Geophys. Res. 85, 1443–1445.Google Scholar
  13. Crane, K., 1985, The Spacing of Rise Axis Highs: Dependence upon Diapiric Processes in the Underlying Asthenosphere, EPSL 72, 405–414.Google Scholar
  14. Crane, K., Aikman, F.III, Embly, R., Hammond, S., Malahoff, A., and Lupton, J., 1985, The Distribution of Geothermal Fields on the Juan de Fuca Ridge, J. Geophys. Res. 90, B1, 727–744.Google Scholar
  15. Crane, K., 1987, Structural Evolution of the East Pacific Rise Axis from 13°10′ N to 10°35′ N: Interpretations from SeaMARC I Data, Tectonophysics 136, 65–124.Google Scholar
  16. Detrick, R. S., Buhl, P., Vera, E., Mutter, J., Orcutt, J., Madsen, J., and Brocher, T., 1987, Multichannel Seismic Imaging of an Axial Magma Chamber Along the East Pacific Rise Between 9° N and 13° N, Nature 326, 35–41.Google Scholar
  17. Elder, J. W., 1967, Transient Convection in a Porous Medium, J. Fluid Mech. 27, 609–623.Google Scholar
  18. Eittreim, S. L., Biscaye, P. E., and Amos, A. F., 1975, Benthic Nepheloid Layers and the Ekman Thermal Pump, J. Geophys. Res. 80, 5061–5067.Google Scholar
  19. Eittreim, S. L., Biscaye, P. E., and Jacobs, S. S., 1983, Bottom Water Observations in the Vema Fracture Zone, J. Geophys. Res. 88, 2609–2614.Google Scholar
  20. Fornari, D. J., Ryan, W. B. F., and Fox, P. J., 1984, The Evolution of Craters and Calderas on Young Seamounts. Insights from SeaMARC I and Sea Beam Sonar Surveys of a Small Seamount Group Near the Axis of the East Pacific Rise at 10° N, J. Geophys. Res. 89, 11,069–11,084.Google Scholar
  21. Gente, P., Auzende, J. M., Renard, V., Fouquet, Y., and Bideau, D. 1986, Detailed Geological Mapping by Submersible on the East Pacific Rise Axial Graben near 13° N. E.P.S.L., 78, 224–236.Google Scholar
  22. Haxby, W. and Weissel, J. K., 1982, Evidence for Small-Scale Mantle Convection from Seasat Altimeter Data, EOS Trans. Am. Geophys. Union 64, 45,838.Google Scholar
  23. Hekinian, R., Francheteau, J., Renard, V., Ballard, R. D., Choukroune, P., Cheminee, J. L., Albarede, F., Minster, J. F., Charlou, J. L., Marty, J. C., and Boulegue, J., 1983, Intense Hydrothermal Activity at the Rise Axis of the East Pacific Rise near 13° N: Submersible Witnesses the Growth of Sulfide Chimney, Mar. Geophys. Res 6, 1–14.Google Scholar
  24. Hekinian, R., Auzende, J. M., Francheteau, J., Gente, P., Ryan, W. B. F., and Kappel, E., 1985, Offset Spreading Centers near 12°53′ N on the East pacific Rise: Submersible Observations and Composition of the Volcanics, Mar. Geophys. Res. 7, 359–377.Google Scholar
  25. Kastens, K. A., Ryan, W. B. F., and Fox, P. J., 1986, The Structural and Volcanic Expression of a Fast-Slipping Ridge-Transform-Ridge Plate Boundary: SeaMARC I and Photographic Surveys at the Clipperton Transform Fault, J. Geophys. Res. 91, B3, 3569–3589.Google Scholar
  26. Little, S. A., Stolzenbach, K. D., and von Herzen, R. P., 1987, Characterization of Plume Flow from a Hydrothermal Vent Field, J. Geophys. Res. (submitted).Google Scholar
  27. Lonsdale, P. and Spiess, F. N., 1980, Deep-Tow Observations at the East Pacific Rise, 8°45′ N and Some Interpretations., Init. Reports of the Deep Sea Drilling Project, V. LIV, Wash. U.S. Govt Printing Office.Google Scholar
  28. Lupton, J. E. and Craig, H., 1981, A Major 3He Source on the EPR, Science 214, 13–18.Google Scholar
  29. Lupton, J. E., Delaney, J. R., Johnson, H. P., and Tivey, M. K., 1985, Entrainment and Vertical Transport of Deep-ocean Water by Buoyant Hydrothermal Plumes, Nature 316, 621–623.Google Scholar
  30. Macdonald, K. C., Sempere, J.-C., and Fox, J. P., 1984, The East Pacific Rise from the Siqueiros to the Orozco Fracture Zones: Along Strike Continuity of the Axial Neovolcanic Zone and the Structure and Evolution of Overlapping Spreading Centers, J. Geophys. Res. 89, B7, 6049–6069.Google Scholar
  31. McConachy, T. F., Ballard, R. D., Mottl, M. J., von Herzen, R. P., 1986, Geologic Form and Setting of a Hydrothermal Vent Field at Lat 10°56′ N East Pacific Rise: A Detailed Study Using Angus and Alvin, Geology 14, 295–298.Google Scholar
  32. Merlivat, L. and Dimon, B., 1982, L'hydrothermalisme sousmarin: Science et Recherche, pp. 73–76.Google Scholar
  33. Reid, J., 1982, Evidence of an Effect of Heat Flux from the East Pacific Rise upon the Characteristics of Mid-depth waters, Geophys. Res. Lett. 9, 381–384.Google Scholar
  34. Riser, S.C., 1988, Helium-3 and Thermal Plumes in the Abyssal South Pacific, J. Phys. Oceanog. (in press).Google Scholar
  35. Rouse, H. C., Yin, C. S., and Humphreys, H. W., 1952, Gravitational Convection from a Boundary Source, Tellus 4, 201–210.Google Scholar
  36. Schouten, H., Klitgord, K. D., and Whitehead, J. A., 1985, Segmentation of Mid-ocean Ridges, Nature 317, 225–229.Google Scholar
  37. Stommel, H. M., 1982, Is the South Pacific 3He Plume Dynamically Active?, EPSL 61, 63–67.Google Scholar
  38. Van Andel, Tj. H. and Ballard, R. D., 1979, The Galapagos Rift at 86° W, 2: Volcanism, Structure and Evolution of the Rift Valley, J. Geophys. Res. 84, 5390–5406.Google Scholar
  39. Weatherly, G. L. and Martin, P. J., 1978, On the Structure and Dynamics of the Oceanic Boundary Layer, J. Phys. Oceanography 8, 557–570.Google Scholar
  40. Wimbush, M. and Munk, W., 1970, The Benthic Boundary Layer, in A.Maxwell (ed.), The Sea, vol. 4, part 1, John Wiley, New York, pp. 731–758.Google Scholar
  41. Wolery, T. J. and Sleep, N. H., 1976, Hydrothermal Circulation and Geochemical Flux at Mid-ocean Ridges, J. Geology. 84, 249.Google Scholar

Copyright information

© Kluwer Academic Publishers 1988

Authors and Affiliations

  • Kathleen Crane
    • 1
    • 2
  • Frank AikmanIII
    • 2
  • Jean-Paul Foucher
    • 3
  1. 1.Dept. of Geology and Geography, Hunter CollegeCUNYU.S.A.
  2. 2.Lamont-Doherty Geological ObservatoryPalisadesU.S.A.
  3. 3.IFREMER Centre de BrestBrestFrance

Personalised recommendations