36. Thickening of the Oceanic Lithosphere

  1. George H. Sutton,
  2. Murli H. Manghnani,
  3. Ralph Moberly and
  4. Ethel U. Mcafee
  1. Toshikatsu Yoshi1,
  2. Yoshiteru Kono2 and
  3. Keisuke Ito3

Published Online: 17 MAR 2013

DOI: 10.1029/GM019p0423

The Geophysics of the Pacific Ocean Basin and Its Margin

The Geophysics of the Pacific Ocean Basin and Its Margin

How to Cite

Yoshi, T., Kono, Y. and Ito, K. (1976) Thickening of the Oceanic Lithosphere, in The Geophysics of the Pacific Ocean Basin and Its Margin (eds G. H. Sutton, M. H. Manghnani, R. Moberly and E. U. Mcafee), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM019p0423

Author Information

  1. 1

    Earthquake Research Institute, University of Tokyo, Tokyo 113, Japan

  2. 2

    Faculty of Science, Kanazawa University, Kanazawa, Japan

  3. 3

    Faculty of Science, Kobe University, Kobe, Japan

Publication History

  1. Published Online: 17 MAR 2013
  2. Published Print: 1 JAN 1976

ISBN Information

Print ISBN: 9780875900193

Online ISBN: 9781118663592

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Keywords:

  • Geophysics—Pacific area—Congresses;
  • Woollard, George Prior, 1908

Summary

A concept of thickening of the oceanic lithosphere is presented. From the ‘residual gravity anomaly' (RGA), defined as a mantle gravity anomaly, the thickness of the lithosphere ℓ (km) is inferred to increase as the sea-floor age t(m.y.) gets older. The relation is given by. A thermal model of the thickening lithosphere is derived so that the lithosphere grows from a molten asthenosphere and the latent heat is released at the lithosphere-asthenosphere boundary. The thermal model is concordant with the thickness of the lithosphere inferred from the RGA. The possible presence of a highly molten asthenosphere just beneath the lithosphere is implied from the thermal model. Surface wave and other geophysical studies strongly support the concept of the thickening of the lithosphere. Petrological considerations suggest a distinct layered structure within the lithosphere; namely, dunite or harzburgite, garnet pyroxenite, and eclogite, from the top to bottom layers.