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Electrical Conductivity: The Story of an Elusive Parameter, and of How it Possibly Relates to the Kapuskasing Uplift (Lithoprobe, Canada)

  • Marianne Mareschal
Part of the NATO ASI Series book series (ASIC, volume 317)

Abstract

Possible sources of crustal conductivity are reviewed, with special emphasis on shield environments. Typical lower crustal conductivities are interpreted in terms of brines and/or graphite films precipitated at grain-boundaries under cooling after peak metamorphism. The nature of the conductive films may strongly depend on the age of the crust: grain-boundary graphite may be present in most lower crusts, while brines would be found in the more active and younger regions. Electromagnetic investigations of the Kapuskasing Uplift confirm that exposed lower crustal rocks are very resistive. Water does not seem to play any significant role in the present lower crust of the uplift, where no correlation between deep seismic reflectors and conductors can apparently be found. Interpretation is only preliminary, however, it also suggests that brines may exist deep in the upper crust (~ 5km). Other shallow conductors could be related to lithologic boundaries, faults or detachment zones.

Keywords

Lower Crust Seismic Reflection Seismic Refraction Conductive Zone Canadian Shield 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • Marianne Mareschal
    • 1
  1. 1.IREM, Ecole PolytechniqueMontréalCanada

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