Electromagnetic images of regional structure in the southern Canadian Cordillera

Alan G. Jones*, D. Ian Gough, Ron D. Kurtz, Jon M. DeLaurier, David E. Boerner, James A. Craven, Rob G. Ellis, Gary W. McNeice

*Corresponding author for this work

    Research output: Contribution to journalArticle

    25 Citations (Scopus)

    Abstract

    As part of Lithoprobe's Southern Cordilleran transect investigations, magnetotelluric (MT) soundings were made at 160 sites providing unprecedented coverage from the Rockies to the west coast. Striking lateral variation, which spatially correlates with the morphogeological belt boundaries, is apparent at periods sensing the lower crust (≈10 s). For the Rockies, MT phases are around 35°, indicative of a moderately resistive (100's – 1000's Ω·m) North American Basement. Foreland belt phases are transitional and increase from 60° in the east to 70° in the west. Omineca and Coast belt phases are high (75°), implying a conductive (10–30 Ω·m) lower crust, whereas Intermontane belt phases are more than 10° lower (equivalent to ≈150 Ω·m). The regional variation in conductivity correlates to first order with surface heat flow changes along the profile and is also correlative with coincident seismic reflection sections in some aspects.

    Original languageEnglish
    Pages (from-to)2373-2376
    Number of pages4
    JournalGeophysical Research Letters
    Volume19
    Issue number24
    DOIs
    Publication statusPublished - 1992

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