Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect
Two‐dimensional inversions of lithospheric‐probing magnetotelluric (MT) data at a total of 20 sites acquired along an approximately east–west 300‐km‐long profile across the Wopmay orogen in the Northwest Territories, Canada, provide electrical resistivity models of the boundary between the Archean S...
Published in: | Journal of Geophysical Research: Solid Earth |
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Online Access: | https://oceanrep.geomar.de/id/eprint/1257/ https://oceanrep.geomar.de/id/eprint/1257/1/911_Spratt_2009_LithosphericGeometryOfTheWopmay_Artzeit_pubid12792.pdf https://doi.org/10.1029/2007JB005326 |
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ftoceanrep:oai:oceanrep.geomar.de:1257 2023-05-15T17:46:44+02:00 Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect Spratt, J. E. Jones, A. G. Jackson, V. A. Collins, L. Avdeeva, Anna 2009 text https://oceanrep.geomar.de/id/eprint/1257/ https://oceanrep.geomar.de/id/eprint/1257/1/911_Spratt_2009_LithosphericGeometryOfTheWopmay_Artzeit_pubid12792.pdf https://doi.org/10.1029/2007JB005326 en eng AGU https://oceanrep.geomar.de/id/eprint/1257/1/911_Spratt_2009_LithosphericGeometryOfTheWopmay_Artzeit_pubid12792.pdf Spratt, J. E., Jones, A. G., Jackson, V. A., Collins, L. and Avdeeva, A. (2009) Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect. Open Access Journal of Geophysical Research: Solid Earth, 114 (B1). B01101. DOI 10.1029/2007JB005326 <https://doi.org/10.1029/2007JB005326>. doi:10.1029/2007JB005326 info:eu-repo/semantics/openAccess Article PeerReviewed 2009 ftoceanrep https://doi.org/10.1029/2007JB005326 2023-04-07T14:43:41Z Two‐dimensional inversions of lithospheric‐probing magnetotelluric (MT) data at a total of 20 sites acquired along an approximately east–west 300‐km‐long profile across the Wopmay orogen in the Northwest Territories, Canada, provide electrical resistivity models of the boundary between the Archean Slave craton and the adjacent Proterozoic Bear Province. An analysis of distortion effects and structural dimensionality indicates that the MT responses are primarily one‐dimensional or only weakly two‐dimensional with a depth‐independent geoelectric strike angle of N32°E, consistent with regional structural geology. The regional‐scale model, generated from the longer period responses from all of the sites along the profile, reveals significant lateral variations in the lithospheric mantle. Resistive cratonic roots are imaged to depths of ∼200 km beneath both the Slave craton and the Hottah terrane of the Bear Province. These are separated by a less resistive region beneath the Great Bear magmatic zone, which is speculatively interpreted as a consequence of a decrease in the grain size of olivine in the Wopmay mantle, caused by localized shearing, compared to its neighboring cratonic roots. Focused two‐dimensional models, from higher frequency responses at sites on specific sections of the profile, reveal the resistivity structure at crustal depths beneath the region. These suggest that the root of the Slave craton crosses beneath the Wopmay orogen, and that the Wopmay fault zone does not penetrate into the lower crust. A comparison of these results with those obtained during the Lithoprobe project farther south shows striking along strike variations in the conductivity structure associated with the Wopmay orogen. Article in Journal/Newspaper Northwest Territories OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Canada Northwest Territories Journal of Geophysical Research: Solid Earth 114 B1 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
Two‐dimensional inversions of lithospheric‐probing magnetotelluric (MT) data at a total of 20 sites acquired along an approximately east–west 300‐km‐long profile across the Wopmay orogen in the Northwest Territories, Canada, provide electrical resistivity models of the boundary between the Archean Slave craton and the adjacent Proterozoic Bear Province. An analysis of distortion effects and structural dimensionality indicates that the MT responses are primarily one‐dimensional or only weakly two‐dimensional with a depth‐independent geoelectric strike angle of N32°E, consistent with regional structural geology. The regional‐scale model, generated from the longer period responses from all of the sites along the profile, reveals significant lateral variations in the lithospheric mantle. Resistive cratonic roots are imaged to depths of ∼200 km beneath both the Slave craton and the Hottah terrane of the Bear Province. These are separated by a less resistive region beneath the Great Bear magmatic zone, which is speculatively interpreted as a consequence of a decrease in the grain size of olivine in the Wopmay mantle, caused by localized shearing, compared to its neighboring cratonic roots. Focused two‐dimensional models, from higher frequency responses at sites on specific sections of the profile, reveal the resistivity structure at crustal depths beneath the region. These suggest that the root of the Slave craton crosses beneath the Wopmay orogen, and that the Wopmay fault zone does not penetrate into the lower crust. A comparison of these results with those obtained during the Lithoprobe project farther south shows striking along strike variations in the conductivity structure associated with the Wopmay orogen. |
format |
Article in Journal/Newspaper |
author |
Spratt, J. E. Jones, A. G. Jackson, V. A. Collins, L. Avdeeva, Anna |
spellingShingle |
Spratt, J. E. Jones, A. G. Jackson, V. A. Collins, L. Avdeeva, Anna Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect |
author_facet |
Spratt, J. E. Jones, A. G. Jackson, V. A. Collins, L. Avdeeva, Anna |
author_sort |
Spratt, J. E. |
title |
Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect |
title_short |
Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect |
title_full |
Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect |
title_fullStr |
Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect |
title_full_unstemmed |
Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect |
title_sort |
lithospheric geometry of the wopmay orogen from a slave craton to bear province magnetotelluric transect |
publisher |
AGU |
publishDate |
2009 |
url |
https://oceanrep.geomar.de/id/eprint/1257/ https://oceanrep.geomar.de/id/eprint/1257/1/911_Spratt_2009_LithosphericGeometryOfTheWopmay_Artzeit_pubid12792.pdf https://doi.org/10.1029/2007JB005326 |
geographic |
Canada Northwest Territories |
geographic_facet |
Canada Northwest Territories |
genre |
Northwest Territories |
genre_facet |
Northwest Territories |
op_relation |
https://oceanrep.geomar.de/id/eprint/1257/1/911_Spratt_2009_LithosphericGeometryOfTheWopmay_Artzeit_pubid12792.pdf Spratt, J. E., Jones, A. G., Jackson, V. A., Collins, L. and Avdeeva, A. (2009) Lithospheric geometry of the Wopmay orogen from a Slave craton to Bear Province magnetotelluric transect. Open Access Journal of Geophysical Research: Solid Earth, 114 (B1). B01101. DOI 10.1029/2007JB005326 <https://doi.org/10.1029/2007JB005326>. doi:10.1029/2007JB005326 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1029/2007JB005326 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
114 |
container_issue |
B1 |
_version_ |
1766150556762505216 |