The Electrical Conductivity of the Oceanic Lithosphere

  1. John G. Heacock
  1. Charles S. Cox

Published Online: 15 MAR 2013

DOI: 10.1029/GM014p0227

The Structure and Physical Properties of the Earth's Crust

The Structure and Physical Properties of the Earth's Crust

How to Cite

Cox, C. S. (1971) The Electrical Conductivity of the Oceanic Lithosphere, in The Structure and Physical Properties of the Earth's Crust (ed J. G. Heacock), American Geophysical Union, Washington D. C.. doi: 10.1029/GM014p0227

Author Information

  1. Scripps Institution of Oceanography, University of California, San Diego California 92037

Publication History

  1. Published Online: 15 MAR 2013
  2. Published Print: 1 JAN 1971

ISBN Information

Print ISBN: 9780875900148

Online ISBN: 9781118664049

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Keywords:

  • Drilled cores;
  • Electrical conductivity;
  • Electromagnetic methods;
  • Oceanic lithosphere;
  • Parkinson's effect;
  • Thermodynamic cycle;
  • Water-saturated basalts

Summary

Methods for learning the distribution of electrical conductivity under the ocean are based on: 1, estimates of temperature and composition of the lithosphere; 2, measurements of natural electromagnetic fields; and 3, direct studies from drill holes or of drilled samples. The first method suffers from uncertainties in the temperature distribution associated with poor knowledge of the thermal conductivity, the influence of heat transported by flow of magma, and of heat produced by plastic flow in the asthenosphere. It is conceivable that the plastic flow in the asthenosphere can produce as much as 25% of the average heat flow and can be concentrated in spots at the base of the lithosphere. The existence of pore fluids greatly increases electrical conductivity. The second method is sensitive only to those parts of the lithosphere whose conductivity approaches that of sea water. There are indications off California and Peru that the subocean lithosphere reaches a conductivity one-tenth that of sea water at a depth of 30 km. The third method is becoming practical through recent development of deep drilling techniques.