The Deep Structure of North American Accreted Terranes from Deep Seismic Reflection Data

  1. John W. Hillhouse
  1. Christopher J. Potter

Published Online: 18 MAR 2013

DOI: 10.1029/GM050p0203

Deep Structure and Past Kinematics of Accreted Terranes

Deep Structure and Past Kinematics of Accreted Terranes

How to Cite

Potter, C. J. (2013) The Deep Structure of North American Accreted Terranes from Deep Seismic Reflection Data, in Deep Structure and Past Kinematics of Accreted Terranes (ed J. W. Hillhouse), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM050p0203

Author Information

  1. Department of Geology, Lafayette College, Easton, Pennsylvania 18042

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875904542

Online ISBN: 9781118666609

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Keywords:

  • Geology, Structural—Congresses;
  • Geodynamics—Congresses;
  • Earth—Crust—Congresses

Summary

Deep seismic data from North American accreted terranes show either: 1) relatively simple patterns related to imbrication and underplating of accreted terranes with a uniform sense of vergence; or 2) very complex, intersecting patterns of dipping reflections. The latter may result from a complex set of thrust faults with opposing senses of vergence, combinations of thrust and strike slip faults, or overprinting in accreted terranes that have experienced complex tectonic histories. Such complex patterns are often difficult to interpret because reflections cannot be traced directly to the surface, and because of ambiguities in interpretation of surface structure. However, reflection patterns in north-central Washington suggest that a major reversal in vergence in Mesozoic thrust structures occurs on either side of an accreted Jurassic arc. Such massive accreted fragments may be instrumental in producing reversals in vergence in orogenic belts.

On some seismic sections from the Appalachians and the Cordillera, it is clear that terrane boundaries do not remain as important crustal structures, but are quite rapidly overprinted by deep crustal magmatic and deformational processes that accompany crustal extension. Thus, terrane boundaries appear to be ephemeral features in orogenic evolution.