Geologic Processes of the Mid-Ocean Ridge and their Relation to Sulfide Deposition

  • Robert D. Ballard
  • Jean Francheteau
Part of the NATO Conference Series book series (NATOCS, volume 12)


Enough detailed data has been obtained along the axis of the Mid-Ocean Ridge to construct a kinematic model which attempts to describe observed variations in time, space, and spreading rate of volcanic, tectonic, and hydrothermal processes and their relationship to the deposition of massive sulfide deposits. Each accretionary segment or accretionary cell bounded by two transform faults is underlain by a unique magma reservoir. Because of cooling at the tranform fault edges, the magma reservoir pinches out and is most developed at a location away from the transform faults. Where the reservoir reaches its fullest development, there is a higher heat flux into the overlying crustal lid. The shallow region where the magma reservoir is most developed and where the crustal lid is thinnest should correspond to the most vigorous hydrothermal activity because of the higher energy content in the system at shallow depths. Because the crustal lid, at the high, is at its minimum thickness, rifting of the lid should result in lava flows having the most direct and shortest path from the magma reservoir to the young seafloor along the rifting axis. At least in the case of moderate to fast spreading segments, the flows nearest the topographic high should be copious surface-fed fluid lavas with the ratio of fluid to pillow flows decreasing down the topographic gradient above a domain of lid thickening. The farther from the topographic high, the more distal and channelized the flows would be resulting in more tube-fed pillow flows. We propose that areas of shallow sea floor at the axis of the Mid-Ocean Ridge are used as a prospecting tool in the search for active sulfide deposition along any given accretion segment. The model draws upon submersible and towed camera mapping programs in the FAMOUS area of the Mid-Atlantic Ridge where the spreading rate is approximately 2 cm/yr. In addition, recent efforts along various segments of the East Pacific Rise and Galapagos Rift have the most profound impact on the model as they involve spreading rates ranging from 6.0 to 10.2 cm/yr where hydrothermal circulation and associated massive sulfide deposition is well developed.


Massive Sulfide Magma Reservoir Topographic High East Pacific Rise Rift Axis 
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.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. ARCYANA, 1975, Transform fault and rift valley from bathyscaph and diving saucer, Science 190: 108–116.Google Scholar
  2. Ballard, R.D. and Francheteau, J., 1982, The relationship between active sulfide deposition and the axial processes of the Mid-Ocean Ridge, J. Mar. Tech. Soc. 16:8–22.Google Scholar
  3. Ballard, R.D., Francheteau, J., Juteau, T., Rangan, C., and Normark, W., 1981, East Pacific Rise at 21N: the volcanic, tectonic, and hydrothermal processes of the central axis, Earth and Plan. Sci. Letters 55:1–10.Google Scholar
  4. Ballard, R.D., Holccamb, R.T., and van Andel, Tj. H., 1979, The Galapagos Rift at 86°W: 3. Sheet flows, collapse pits, and lava lakes of the rift valley, J. Geophys. Res. 84: 5407–5422.Google Scholar
  5. Ballard, R.D., Morton, J., and Francheteau, J., 1981, Geology and high temperature hydrothermal circulation of ultra-fast spreading ridge: East Pacific Rise at 20°S, EOS, 62: 912.Google Scholar
  6. Ballard, R.D., van Andel, Tj. H., and Holcomb, R.T., 1982, The Galapagos Rift at 86°W: 5. Variations in volcanism, structure, and hydrothermal activity along a 30 km segment of the rift valley, J. Geophys. Res. 87: 1149–1161.Google Scholar
  7. Ballard, R.D., and van Andel, Tj. H., 1977, Project FAMOUS: Morphology and tectonics of the inner rift valley at 36°50’N on the Mid-Atlantic Ridge, Geol. Soc. Amer. Bull. 88: 507–530.Google Scholar
  8. Crane, K., 1978, Structure and tectonogenesis of the Galapagos inner rift, 86 10’W, J. Geol. 86:715–730.Google Scholar
  9. CYAMEX Scientific Team, 1981, First manned submersible dives on the East Pacific Rise 21 N (Project RITA): General results, Mar. Geophys. Res. 4:345–379.Google Scholar
  10. CYAMEX Scientific Team, 1979, Massive deep-sea sulphide ore deposits discovered on the East Pacific Rise, Nature 277: 523–528.Google Scholar
  11. Francheteau, J. and Ballard, R.D., in press, The East Pacific Rise near 21 N, 13 N and 20 S: inferences for along-strike variability of axial processes of the Mid-Ocean Ridge, Earth and Plan. Sci. Letters. Google Scholar
  12. Lonsdale, P., 1977, Structural geomorphology of a fast-spreading rise crest: The East Pacific Rise near 3 25’S, Mar. Geophys. Res. 3:251–294.Google Scholar
  13. Lansdale, P.F., 1974, Abyssal pahoehoe with lava whorls at the Galapagos Rift, Geology 5: 147–152.Google Scholar
  14. Moore, J.G., Fleming, H.S., and Phillips, J.D., 1974, Preliminary model for the extrusion and rifting at the axis of the Mid-Atlantic Ridge, 36°48’North, Geology 2: 437–450.Google Scholar
  15. Phillips, J.D., and Fleming, H.S., 1978, Multibeam sonar study of the Mid-Atlantic Ridge rift valley, 36–37N, Geol. Soc. Am. Map Series, MC-19.Google Scholar
  16. RISE Project Group, 1980, East Pacific Rise: Hot springs and geophysical experiments, Science 207: 1421–1433.Google Scholar
  17. Sclater, J.G., Parsons, B., and Jaupart, C., 1981, Oceans and continents: similarities and differences in the mechanisms of heat loss, J. Geophys. Res. 86:11535–11552.Google Scholar
  18. Sleep, N., and Biehler, S., 1970, Topography and tectonics at the intersections of fracture zones with central rifts, J. Geophys. Res. 75:2748–2752.Google Scholar
  19. 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: 5390–5406Google Scholar

Copyright information

© Springer Science+Business Media New York 1983

Authors and Affiliations

  • Robert D. Ballard
    • 1
    • 2
  • Jean Francheteau
    • 1
    • 2
  1. 1.Woods Hole Oceanographic InstitutionWoods HoleUSA
  2. 2.Centre Oceanologique de BretagneBrest CedexFrance

Personalised recommendations