Seismic Reflection Profiles of Precambrian Crust: A Qualitative Assessment

  1. Muawia Barazangi and
  2. Larry Brown
  1. Allan K. Gibbs

Published Online: 15 MAR 2013

DOI: 10.1029/GD014p0095

Reflection Seismology: The Continental Crust

Reflection Seismology: The Continental Crust

How to Cite

Gibbs, A. K. (1986) Seismic Reflection Profiles of Precambrian Crust: A Qualitative Assessment, in Reflection Seismology: The Continental Crust (eds M. Barazangi and L. Brown), American Geophysical Union, Washington, D. C.. doi: 10.1029/GD014p0095

Author Information

  1. Institute for the Study of the Continents, Cornell University, Ithaca, New York 14853

Publication History

  1. Published Online: 15 MAR 2013
  2. Published Print: 1 JAN 1986

Book Series:

  1. Geodynamics Series

ISBN Information

Print ISBN: 9780875905143

Online ISBN: 9781118670118

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Keywords:

  • Earth—Crust—Congresses;
  • Continents—Congresses;
  • Seismic reflection method—Congresses

Summary

Seismic reflection profiles of Precambrian terranes reveal some structural features that were probably developed in Precambrian times. Seismically transparent zones are associated with granitoid rocks, anorthosites, and gneisses; zones of stratified, relatively continuous upper crustal reflection are typical of Precambrian continental sedimentary basins; relatively continuous, coherent, moderately-dipping reflection zones are associated with faults at Precambrian terrane boundaries; and zones of complex reflections and diffractions occur in gneiss terranes and basement to continental sedimentary basins. Features at Mono depths are typically weak or barely perceptible, discontinuous, and in some instances appear to have moderate dips. The base of the crust is revealed elsewhere by a decrease in the abundance of reflections. The similarity of structures in Archean, Proterozoic, and Phanerozoic crust may be due to qualitatively similar tectonic processes in all eras. The retention of Precambrian structures in middle and lower crust implies that such crust has remained coherent through subsequent time.