Galapagos

Galapagos bathymetry.

Click on the above image to see a full-size version of the color-shaded relief map, with caption.

Propagation Models.

Click on the above image to see a full-size version of various models of propagating rift geometry, with caption.

The Galapagos 95.5°;W propagator was the first active propagating rift discovered. In addition to routine geophysical techniques, an OBS array and dredging, this area has been surveyed with GLORIA, SeaMARC II, SeaBeam, Deep-Tow, and ALVIN, and has become the type-example propagating rift system. This figure is a color-shaded relief map of SeaBeam bathymetry from Hey et al. (1986). The NW-SE trending structures between the propagating and failing ridges are incompatible with previous plate tectonic theory but are a predictable consequence of the rift propagation hypothesis.

The geometry of the propagating rift and shear zone are most closely matched by the broad "non-transform" zone geometry in model C at lower left, whereas rift failure has been discontinuous as in model A. Outside of the area bounded by the outer pseudofault, the transform, and the failed rift, classic plate tectonic geometry is valid.

As it turned out, this work provided an explanation for one of the most famous data sets in marine geophysics, the Juan de Fuca magnetic anomaly pattern.

Publications

  • Hey, R.N., K.S. Deffeyes, G.L. Johnson, and A. Lowrie, The Galapagos triple junction and plate motions in the East Pacific, Nature, 237, 20-22, 1972.
  • Hey, R.N., Tectonic evolution of the Cocos-Nazca rise, Ph.D. Thesis, Department of Geological and Geophysical Sciences, Princeton University, 169, 1975.
  • Johnson, G.L., P.R. Vogt, R.N. Hey, J. Campsie, and A. Lowrie, Morphology and structure of the Galapagos rise, Marine Geophysical Research, 21, 81-120, 1976.
  • Hey, R.N. and P.R. Vogt, Spreading center jumps and sub-axial asthenosphere flow near the Galapagos hotspot, Tectonophysics, 37, 41-52, 1977.
  • Hey, R.N., G.L. Johnson, and A. Lowrie, Recent plate motions in the Galapagos area, Geol. Soc. Am. Bull., 88, 1385-1403, 1977.
  • Hey, R.N., Tectonic evolution of the Cocos-Nazca spreading center, Geol. Soc. Am. Bull., 88, 1404-1420, 1977.
  • Hey, R.N., Evidence for spreading center jumps from fine-scale bathymetry and magnetic anomalies near the Galapagos Islands, Geology, 7, 504-506, 1979.
  • Hey, R.N., F.K. Duennebier, and W.J. Morgan, Propagating rifts on mid-ocean ridges, J. Geophys. Res., 85, 3647-3658, 1980.
  • Wilson, D.S. and R.N. Hey, The Galapagos axial magnetic anomaly: Evidence for the Emperor event within the Brunhes and for a two-layer magnetic source, Geophys. Res. Lett., 8, 167-188, 1981.
  • Sinton, J.M., D.S. Wilson, D.M. Christie, R.N. Hey, and J.R. Delaney, Petrologic consequences of rift propagation on oceanic spreading ridges, Earth Planet. Sci. Lett., 62, 193-207, 1983.
  • Searle, R.C. and R.N. Hey, GLORIA observations of the propagating rift at 95.5°;W on the Cocos-Nazca spreading center, J. Geophys. Res., 88, 6433-6447, 1983.
  • Hey, R.N., High-technology investigations of rift propagation and plate tectonics, Proceedings OCEAN's 83, Inst. of Electrical and Electronics Engineers/Marine Technology Society, 2, 791-796, 1983.
  • Hey, R.N., M.C. Kleinrock, S.P. Miller, T.M. Atwater, and R.C. Searle, Sea Beam/Deep-Tow investigation of an active oceanic propagating rift system, J. Geophys. Res., 91, 3369-3393, 1986.
  • Miller, S.P. and R.N. Hey, 3-D magnetic modelling of a propagating rift, Galapagos 95.5°;W, J. Geophys. Res., 91, 3395-3406, 1986.
  • Schubert, G. and R.N. Hey, Mantle viscosity beneath the Galapagos 95.5°;W propagating rift, Geophys. Res. Lett., 13, 329-332, 1986.
  • Miller, S.P. and R.N. Hey, A magnetic investigation of a tectonic problem: The propagating rift, Galapagos 95°; 30'W, J. Geodynamics, 5, 1-24, 1986.
  • Hey, R.N., J.M. Sinton, and F.K. Duennebier, Propagating rifts and spreading centers, in Decade of North American Geology: The Eastern Pacific Ocean and Hawaii, Geological Society of America, 161-176, 1989.
  • Kleinrock, M.C. and R.N. Hey, Detailed tectonics near the tip of the Galapagos 95.5°W propagator: How the lithosphere tears and a spreading axis develops, J. Geophys. Res., 94, 13801-13838, 1989.
  • Kleinrock, M.C., R.C. Searle, and R.N. Hey, Tectonics of the failing spreading system associated with the 95.5°W Galapagos propagator, J. Geophys. Res., 94, 13839-13858, 1989.
  • Kleinrock, M.C. and R.N. Hey, Migrating transform zone and lithospheric transfer at the Galapagos 95.5°W propagator, J. Geophys. Res., 94, 13859-13878, 1989.
  • Hey, R.N., J.M. Sinton, M.C. Kleinrock, R.N. Yonover, K.C. Macdonald, S.P. Miller, R.C. Searle, D.M. Christie, T.M. Atwater, N.H. Sleep, H.P. Johnson, and C.A. Neal, 1992, ALVIN investigation of an active propagating rift system, Galapagos 95.5°W, Marine Geophys. Res., 14, 207-226.
  • Kleinrock, M.C., R.N. Hey, and A.E. Theberge, Practical geological comparison of some seafloor survey instruments, Geophys. Res. Lett., 19, 1407-1410, 1992.
  • Wilson, D.S. and R.N. Hey, History of rift propagation and magnetization intensity for the Cocos-Nazca spreading center, J. Geophys. Res., 100, 10041-10056, 1995.
  • Hey, R.N., Propagating Rifts and Microplates, in Encyclopedia of Ocean Sciences, eds. J.H. Steele, S.A.Thorpe, and K.K. Turekian, Academic Press, London, Volume 4, 2300-2308, 2001.
  • Hey, R.N., Propagating Rifts and Microplates at Mid-Ocean Ridges, in Encyclopedia of Geology, eds. R.C. Selley, R. Cocks and I. Plimer, Academic Press, London, 396-405, 2004.

Oceanographic Expeditions

  • 1970 May–June: Pacific-Cocos-Nazca triple junction survey, Panama-Panama, Princeton University/U.S. Navy, chief scientist K.S. Deffeyes, USNS DE STEIGUER.
  • ** 1979 March–May: Investigations of propagating rifts west of the Galapagos Islands, Acapulco-Santa Cruz, Galapagos, Hawaii Institute of Geophysics, chief scientist R.N. Hey, R/V KANA KEOKI.
  • ** 1979 May: Galapagos Islands rock sampling cruise, Santa Cruz-Santa Cruz, Galapagos, Hawaii Institute of Geophysics/Darwin Research Station, chief scientist R.N. Hey, Barco SAN JUAN.
  • ** 1979 May–June: Investigations of propagating rifts east of the Galapagos Islands, Puerto San Jose, Guatemala-Santa Cruz, Galapagos, Hawaii Institute of Geophysics, chief scientist R.N. Hey, R/V KANA KEOKI.
  • ** 1982 September–October: Sea Beam/Deep-Tow investigation of the Galapagos 95.5°W propagating rift system, Panama-Manzanillo-San Diego, Scripps Institution of Oceanography, chief scientist R.N. Hey, R/V THOMAS WASHINGTON.
  • *1985 January: SeaMARC II investigation of the Galapagos 95.5°W propagator, Galapagos-Galapagos, Hawaii Institute of Geophysics, chief scientist F.K. Duennebier, R/V MOANA WAVE.
  • **1985 April–May: ALVIN/AII investigation of the Galapagos 95.5°W propagating rift system, Puntarenas, Costa Rica-Acapulco, Scripps Institution of Oceanography/Woods Hole Oceanographic Institution, chief scientist R.N. Hey, R/V ATLANTIS II, DSRV ALVIN.

Students involved in this research

 

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