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Origin of deep crystal reflections: Seismic profiling across high-grade metamorphic terranes in Canada

Tectonophysics

By:
, , , , , , , , , , and
https://doi.org/10.1016/0040-1951(90)90250-C

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Abstract

In an attempt to better understand the origin of deep crustal reflections LITHOPROBE has sponsored or co-sponsored Seismic reflection surveys across tracts of high-grade metamorphic rock in the Archean Superior craton, the Proterozoic Grenville orogen and the Phanerozoic Cordilleran orogen. Common to these three diverse terranes are near-surface zones of prominent Seismic reflectivity that are typically associated with velocity discontinuities at highly strained contacts between gneissic rocks of varying lithology. At some locations the reflective layering resulted from transposition and rearrangement of previously layered rocks (stratified assemblages, sills, etc.), whereas in other regions it was generated by extreme attenuation, stretching and ductile flow of weakly layered or irregularly organized rocks. It seems likely that compositionally layered gneissic rock is a common source of reflections in the deep crust, with reflections originating at lithological boundaries and zones of mylonite. 

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Origin of deep crystal reflections: Seismic profiling across high-grade metamorphic terranes in Canada
Series title:
Tectonophysics
DOI:
10.1016/0040-1951(90)90250-C
Volume:
173
Issue:
1-4
Year Published:
1990
Language:
English
Publisher:
Elsevier
Contributing office(s):
Woods Hole Coastal and Marine Science Center
Description:
12 p.
First page:
627
Last page:
638
Country:
Canada