Wide-angle seismic imaging of pristine Archean crust in the Nain Province, Labrador
A detailed refraction - wide-angle reflection seismic experiment was carried out in northern Labrador to determine the velocity structure of relatively unaltered Archean crust in the Nain Province. Six 3-component land seismometers were used to record an airgun source along a profile parallel to the...
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Canadian Science Publishing
1998
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Online Access: | http://dx.doi.org/10.1139/e98-019 http://www.nrcresearchpress.com/doi/pdf/10.1139/e98-019 |
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crcansciencepubl:10.1139/e98-019 2024-09-15T18:19:02+00:00 Wide-angle seismic imaging of pristine Archean crust in the Nain Province, Labrador Funck, Thomas Louden, Keith E 1998 http://dx.doi.org/10.1139/e98-019 http://www.nrcresearchpress.com/doi/pdf/10.1139/e98-019 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 35, issue 6, page 672-685 ISSN 0008-4077 1480-3313 journal-article 1998 crcansciencepubl https://doi.org/10.1139/e98-019 2024-08-01T04:10:03Z A detailed refraction - wide-angle reflection seismic experiment was carried out in northern Labrador to determine the velocity structure of relatively unaltered Archean crust in the Nain Province. Six 3-component land seismometers were used to record an airgun source along a profile parallel to the coast. Forward modeling of traveltimes and amplitudes yields a P- and S-wave velocity model that shows two crustal blocks separated by a fault. Magnetic data suggest, but do not prove, that the fault is the offshore continuation of the Handy fault. A southwards thickening of the lower crust across the fault indicates that a transcurrent component might have been associated with the faulting. The total crustal thickness is 33 km to the north and 38 km to the south of the fault. The presence of P m S reflections imply a sharp transition at the Moho. Upper crustal velocities of 5.8-6.3 km/s and Poisson's ratios of 0.20 and 0.24, north and south of the fault respectively, are consistent with a gneissic composition, but suggest a higher quartz content in the northern block. Velocities in the middle crust increase to 6.5 km/s, where a discontinuity at a depth between 16 and 18 km marks the transition to the lower crust with velocities between 6.6 and 6.9 km/s. Poisson's ratios of 0.24 and 0.26 indicate, respectively, a felsic middle crust and an intermediate composition for the lower crust. The absence of a high-velocity basal layer is in accordance with other examples of Archean crust. Article in Journal/Newspaper Nain Canadian Science Publishing Canadian Journal of Earth Sciences 35 6 672 685 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
A detailed refraction - wide-angle reflection seismic experiment was carried out in northern Labrador to determine the velocity structure of relatively unaltered Archean crust in the Nain Province. Six 3-component land seismometers were used to record an airgun source along a profile parallel to the coast. Forward modeling of traveltimes and amplitudes yields a P- and S-wave velocity model that shows two crustal blocks separated by a fault. Magnetic data suggest, but do not prove, that the fault is the offshore continuation of the Handy fault. A southwards thickening of the lower crust across the fault indicates that a transcurrent component might have been associated with the faulting. The total crustal thickness is 33 km to the north and 38 km to the south of the fault. The presence of P m S reflections imply a sharp transition at the Moho. Upper crustal velocities of 5.8-6.3 km/s and Poisson's ratios of 0.20 and 0.24, north and south of the fault respectively, are consistent with a gneissic composition, but suggest a higher quartz content in the northern block. Velocities in the middle crust increase to 6.5 km/s, where a discontinuity at a depth between 16 and 18 km marks the transition to the lower crust with velocities between 6.6 and 6.9 km/s. Poisson's ratios of 0.24 and 0.26 indicate, respectively, a felsic middle crust and an intermediate composition for the lower crust. The absence of a high-velocity basal layer is in accordance with other examples of Archean crust. |
format |
Article in Journal/Newspaper |
author |
Funck, Thomas Louden, Keith E |
spellingShingle |
Funck, Thomas Louden, Keith E Wide-angle seismic imaging of pristine Archean crust in the Nain Province, Labrador |
author_facet |
Funck, Thomas Louden, Keith E |
author_sort |
Funck, Thomas |
title |
Wide-angle seismic imaging of pristine Archean crust in the Nain Province, Labrador |
title_short |
Wide-angle seismic imaging of pristine Archean crust in the Nain Province, Labrador |
title_full |
Wide-angle seismic imaging of pristine Archean crust in the Nain Province, Labrador |
title_fullStr |
Wide-angle seismic imaging of pristine Archean crust in the Nain Province, Labrador |
title_full_unstemmed |
Wide-angle seismic imaging of pristine Archean crust in the Nain Province, Labrador |
title_sort |
wide-angle seismic imaging of pristine archean crust in the nain province, labrador |
publisher |
Canadian Science Publishing |
publishDate |
1998 |
url |
http://dx.doi.org/10.1139/e98-019 http://www.nrcresearchpress.com/doi/pdf/10.1139/e98-019 |
genre |
Nain |
genre_facet |
Nain |
op_source |
Canadian Journal of Earth Sciences volume 35, issue 6, page 672-685 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e98-019 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
35 |
container_issue |
6 |
container_start_page |
672 |
op_container_end_page |
685 |
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1810457133342261248 |