North Pacific Sediment Layers Measured by Seismic Profiling

  1. Leon Knopoff,
  2. Charles L. Drake and
  3. Pembroke J. Hart
  1. John Ewing,
  2. Maurice Ewing,
  3. Thomas Aitken and
  4. William J. Ludwig

Published Online: 18 MAR 2013

DOI: 10.1029/GM012p0147

The Crust and Upper Mantle of the Pacific Area

The Crust and Upper Mantle of the Pacific Area

How to Cite

Ewing, J., Ewing, M., Aitken, T. and Ludwig, W. J. (2012) North Pacific Sediment Layers Measured by Seismic Profiling, in The Crust and Upper Mantle of the Pacific Area (eds L. Knopoff, C. L. Drake and P. J. Hart), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM012p0147

Author Information

  1. Lamont Geological Observatory, Columbia University, Palisades, New York

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 20 APR 2012

Book Series:

  1. Geophysical Monograph Series

Book Series Editors:

  1. Waldo E. Smith

ISBN Information

Print ISBN: 9780875900124

Online ISBN: 9781118663738



  • Episodic and continuous spreading;
  • Horizon B and equatorial belt;
  • Northeast and northwest Pacific sediment bodys;
  • North Pacific Ocean;
  • Seismic profile and Darwin rise;
  • Static Ocean floor and turbidite deposits;
  • Transparent and opaque layers;
  • Western Pacific basin and Philippine Sea


A reconnaissance survey of the sediment thickness in the North Pacific Ocean has been accomplished through the use of the continuous seismic profiler. A major division in the sediment cover, based on acoustic properties, is recognized and, according to the evidence from sediment cores, corresponds approximately to the Mesozoic-Cenozoic boundary. It thus appears that most, if not all, pre-Cenozoic sediments are in the western part of the basin, generally west of Hawaii. The pattern of accumulation of the Cenozoic sediments closely resembles the present pattern of biological productivity. The major accumulations, aside from turbidites, are found in a belt approximately following the equator and in a belt along the western and northwestern margin of the basin. Deposition in the central part of the basin appears to have been extremely slow throughout the Cenozoic. There is a marked decrease in the thickness of the equatorial sediment belt over the crest of the East Pacific rise, apparently supporting the concept of a spreading sea floor. However, the over-all agreement between the patterns of sediment accumulation and productivity indicates that deposition during much of the Cenozoic occurred under conditions closely resembling those now obtaining. It is concluded that episodic spreading of the sea floor best accounts for the sediment distribution and that the present cycle of spreading commenced approximately 10 to 12 million years ago, having been preceded by a quiescent period of at least 15 million years' duration.