The Quebec-Western Maine Seismic Reflection Profile: Setting and First Year Results

  1. Muawia Barazangi and
  2. Larry Brown
  1. D. B. Stewart1,
  2. J. D. Unger2,
  3. J. D. Phillips3,
  4. R. Goldsmith4,
  5. W. H. Poole5,
  6. C. P. Spencer,
  7. A. G. Green,
  8. M. C. Loiselle and
  9. P. St-Julien

Published Online: 15 MAR 2013

DOI: 10.1029/GD014p0189

Reflection Seismology: The Continental Crust

Reflection Seismology: The Continental Crust

How to Cite

Stewart, D. B., Unger, J. D., Phillips, J. D., Goldsmith, R., Poole, W. H., Spencer, C. P., Green, A. G., Loiselle, M. C. and St-Julien, P. (1986) The Quebec-Western Maine Seismic Reflection Profile: Setting and First Year Results, in Reflection Seismology: The Continental Crust (eds M. Barazangi and L. Brown), American Geophysical Union, Washington, D. C.. doi: 10.1029/GD014p0189

Author Information

  1. 1

    U.S. Geological Survey, Reston, Virginia 22092

  2. 2

    Geological Survey of Canada, Ottawa, Ontario K1A 0E8

  3. 3

    Earth Physics Branch, Ottawa, Ontario KIA 0Y3

  4. 4

    Maine Geological Survey, Augusta, Maine 04333

  5. 5

    Department of Geology, Laval University, Quebec, Quebec G1K 7P4

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

The Quebec-Western Maine seismic reflection profile is part of a nearly continuous profile about 1000 km long across the Northern Appalachian orogen from the craton to the ocean basin. During 1983, 219 km of 800-channel sign-bit data were collected for 15 seconds two-way travel time using VIBROSEIS sources. Variable upsweeps from 7 to 45 Hz with a 12 km -0–12 km spread, 30 m group intervals, and 90 m vibration points were used. The profiles obtained have nominal 133 fold, and numerous reflectors can be seen at depths corresponding to two-way travel times of 1 to 12 seconds (about 3–42 km). This paper summarizes the regional geology, gravity and magnetic fields, and velocity structure from seismic refraction.

Preliminary interpretations are given for parts of three seismic reflection profiles. Rocks of the Connecticut Valley-Gaspe synclinorium and Chain Lakes massif are allochthonous above a major regional decollement that dips south from a two-way travel time of 3–5 seconds in Quebec to 7.8 seconds beneath the southern part of the massif. Profiles in central and coastal Maine image the shapes of plutons to below 3 seconds, offsets on steep faults to over 7 seconds, and many subhorizontal reflectors at various depths. The 800-channel sign-bit method gave high quality shallow and deep data that correlate well with geologic, gravity, and magnetic data.