A New Hypothesis for Origin of Guyots and Seamount Terraces

  1. Gordon A. Macdonald and
  2. Hisashi Kuno
  1. Y. Rammohanroy Nayudu

Published Online: 21 MAR 2013

DOI: 10.1029/GM006p0171

The Crust of the Pacific Basin

The Crust of the Pacific Basin

How to Cite

Rammohanroy Nayudu, Y. (1962) A New Hypothesis for Origin of Guyots and Seamount Terraces, in The Crust of the Pacific Basin (eds G. A. Macdonald and H. Kuno), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM006p0171

Author Information

  1. Department of Oceanography, University of Washington, Seattle, Washington

Publication History

  1. Published Online: 21 MAR 2013
  2. Published Print: 1 JAN 1962

Book Series:

  1. Geophysical Monograph Series

Book Series Editors:

  1. Waldo E. Smith

ISBN Information

Print ISBN: 9780875900063

Online ISBN: 9781118669310



  • Cobb Seamount;
  • Guyots and Seamount terraces;
  • Palagonitization;
  • Siderornelane;
  • Submarine eruption


A number of different volcanic rock types were dredged from the summit terraces of Cobb Seamount off the coast of the State of Washington and Bowie Bank off the coast of British Columbia, Canada. Palagonite tuff is the most common rock type. Fragments of crystals and basaltic glass, angular to rounded, ranging from sand to granule sizes, are set in the palagonite matrix. These rocks closely resemble complexes of pillow lava and bedded palagonite breccia formed where flows of Columbia River basalts entered lakes and therefore are considered to be primary palagonite tuffs. The remainder of the dredged material consists of angular to subrounded boulders which are considered to be unaltered solid parts of the pillow palagonite complex, concentrated locally by the removal of the palagonite matrix by currents. It is concluded that the terraces of Cobb and Bowie Bank are primary volcanic features rather than wave planation surfaces.