Electrical resistivity structure of the Great Slave Lake shear zone, northwest Canada: implications for tectonic history
Three magnetotelluric (MT) profiles in northwestern Canada cross the central and western segments of Great Slave Lake shear zone (GSLsz), a continental scale strike-slip structure active during the Slave-Rae collision in the Proterozoic. Dimensionality analysis indicates that (i) the resistivity str...
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fthighwire:oai:open-archive.highwire.org:gji:199/1/178 2023-05-15T16:23:05+02:00 Electrical resistivity structure of the Great Slave Lake shear zone, northwest Canada: implications for tectonic history Yin, Yaotian Unsworth, Martyn Liddell, Mitch Pana, Dinu Craven, James A. 2014-08-01 17:08:46.0 text/html http://gji.oxfordjournals.org/cgi/content/short/199/1/178 https://doi.org/10.1093/gji/ggu251 en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/199/1/178 http://dx.doi.org/10.1093/gji/ggu251 Copyright (C) 2014, Oxford University Press Seismology TEXT 2014 fthighwire https://doi.org/10.1093/gji/ggu251 2016-11-16T17:01:10Z Three magnetotelluric (MT) profiles in northwestern Canada cross the central and western segments of Great Slave Lake shear zone (GSLsz), a continental scale strike-slip structure active during the Slave-Rae collision in the Proterozoic. Dimensionality analysis indicates that (i) the resistivity structure is approximately 2-D with a geoelectric strike direction close to the dominant geological strike of N45°E and that (ii) electrical anisotropy may be present in the crust beneath the two southernmost profiles. Isotropic and anisotropic 2-D inversion and isotropic 3-D inversions show different resistivity structures on different segments of the shear zone. The GSLsz is imaged as a high resistivity zone (>5000 Ω m) that is at least 20 km wide and extends to a depth of at least 50 km on the northern profile. On the southern two profiles, the resistive zone is confined to the upper crust and pierces an east-dipping crustal conductor. Inversions show that this dipping conductor may be anisotropic, likely caused by conductive materials filling a network of fractures with a preferred spatial orientation. These conductive regions would have been disrupted by strike-slip, ductile deformation on the GSLsz that formed granulite to greenschist facies mylonite belts. The pre-dominantly granulite facies mylonites are resistive and explain why the GSLsz appears as a resistive structure piercing the east-dipping anisotropic layer. The absence of a dipping anisotropic/conductive layer on the northern MT profile, located on the central segment of the GSLsz, is consistent with the lack of subduction at this location as predicted by geological and tectonic models. Text Great Slave Lake HighWire Press (Stanford University) Canada Great Slave Lake ENVELOPE(-114.001,-114.001,61.500,61.500) Rae ENVELOPE(-116.053,-116.053,62.834,62.834) Geophysical Journal International 199 1 178 199 |
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HighWire Press (Stanford University) |
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fthighwire |
language |
English |
topic |
Seismology |
spellingShingle |
Seismology Yin, Yaotian Unsworth, Martyn Liddell, Mitch Pana, Dinu Craven, James A. Electrical resistivity structure of the Great Slave Lake shear zone, northwest Canada: implications for tectonic history |
topic_facet |
Seismology |
description |
Three magnetotelluric (MT) profiles in northwestern Canada cross the central and western segments of Great Slave Lake shear zone (GSLsz), a continental scale strike-slip structure active during the Slave-Rae collision in the Proterozoic. Dimensionality analysis indicates that (i) the resistivity structure is approximately 2-D with a geoelectric strike direction close to the dominant geological strike of N45°E and that (ii) electrical anisotropy may be present in the crust beneath the two southernmost profiles. Isotropic and anisotropic 2-D inversion and isotropic 3-D inversions show different resistivity structures on different segments of the shear zone. The GSLsz is imaged as a high resistivity zone (>5000 Ω m) that is at least 20 km wide and extends to a depth of at least 50 km on the northern profile. On the southern two profiles, the resistive zone is confined to the upper crust and pierces an east-dipping crustal conductor. Inversions show that this dipping conductor may be anisotropic, likely caused by conductive materials filling a network of fractures with a preferred spatial orientation. These conductive regions would have been disrupted by strike-slip, ductile deformation on the GSLsz that formed granulite to greenschist facies mylonite belts. The pre-dominantly granulite facies mylonites are resistive and explain why the GSLsz appears as a resistive structure piercing the east-dipping anisotropic layer. The absence of a dipping anisotropic/conductive layer on the northern MT profile, located on the central segment of the GSLsz, is consistent with the lack of subduction at this location as predicted by geological and tectonic models. |
format |
Text |
author |
Yin, Yaotian Unsworth, Martyn Liddell, Mitch Pana, Dinu Craven, James A. |
author_facet |
Yin, Yaotian Unsworth, Martyn Liddell, Mitch Pana, Dinu Craven, James A. |
author_sort |
Yin, Yaotian |
title |
Electrical resistivity structure of the Great Slave Lake shear zone, northwest Canada: implications for tectonic history |
title_short |
Electrical resistivity structure of the Great Slave Lake shear zone, northwest Canada: implications for tectonic history |
title_full |
Electrical resistivity structure of the Great Slave Lake shear zone, northwest Canada: implications for tectonic history |
title_fullStr |
Electrical resistivity structure of the Great Slave Lake shear zone, northwest Canada: implications for tectonic history |
title_full_unstemmed |
Electrical resistivity structure of the Great Slave Lake shear zone, northwest Canada: implications for tectonic history |
title_sort |
electrical resistivity structure of the great slave lake shear zone, northwest canada: implications for tectonic history |
publisher |
Oxford University Press |
publishDate |
2014 |
url |
http://gji.oxfordjournals.org/cgi/content/short/199/1/178 https://doi.org/10.1093/gji/ggu251 |
long_lat |
ENVELOPE(-114.001,-114.001,61.500,61.500) ENVELOPE(-116.053,-116.053,62.834,62.834) |
geographic |
Canada Great Slave Lake Rae |
geographic_facet |
Canada Great Slave Lake Rae |
genre |
Great Slave Lake |
genre_facet |
Great Slave Lake |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/199/1/178 http://dx.doi.org/10.1093/gji/ggu251 |
op_rights |
Copyright (C) 2014, Oxford University Press |
op_doi |
https://doi.org/10.1093/gji/ggu251 |
container_title |
Geophysical Journal International |
container_volume |
199 |
container_issue |
1 |
container_start_page |
178 |
op_container_end_page |
199 |
_version_ |
1766011270655377408 |