The structure of Archean–Ketilidian crust along the continental shelf of southwestern Greenland from a seismic refraction profile
The velocity structure of the continental crust on the outer shelf of southwestern Greenland is determined from dense wide-angle reflection–refraction data obtained with large air-gun sources and ocean bottom seismometers along a 230 km seismic line. This line crosses the geological boundary between...
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Canadian Science Publishing
1992
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crcansciencepubl:10.1139/e92-027 2024-09-15T18:09:22+00:00 The structure of Archean–Ketilidian crust along the continental shelf of southwestern Greenland from a seismic refraction profile Chian, Deping Louden, Keith 1992 http://dx.doi.org/10.1139/e92-027 http://www.nrcresearchpress.com/doi/pdf/10.1139/e92-027 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 29, issue 2, page 301-313 ISSN 0008-4077 1480-3313 journal-article 1992 crcansciencepubl https://doi.org/10.1139/e92-027 2024-08-01T04:10:04Z The velocity structure of the continental crust on the outer shelf of southwestern Greenland is determined from dense wide-angle reflection–refraction data obtained with large air-gun sources and ocean bottom seismometers along a 230 km seismic line. This line crosses the geological boundary between the Archean block and the Ketilidian mobile belt. Although the data have high noise levels, P- and S-wave arrivals from within the upper, intermediate, and lower crust, and at the Moho boundary, can be consistently identified and correlated with one-dimensional WKBJ synthetic seismograms. In the Archean, P- and S-wave velocities in the upper crust are 6.0 and 3.4 km/s, while in the intermediate crust they are 6.4 and 3.6 km/s. These velocities match for the upper crust a quartz–feldspar gneiss composition and for the intermediate crust an amphibolitized pyroxene granulite. In the Ketilidian mobile belt, P- and S-wave velocities are 5.6 and 3.3 km/s for the upper crust and 6.3 and 3.6 km/s for the intermediate crust. These velocities may represent quartz granite in the upper crust and granite and granitic gneiss in the intermediate crust. The upper crust is ~5 km thick in the Archean block and the Ketilidian mobile belt, and thickens to ~9 km in the southern part of the Archean. This velocity structure supports a Precambrian collisional mechanism between the Archean block and Ketilidian mobile belt. The lower crust has a small vertical velocity gradient from 6.6 km/s at 15 km depth to 6.9 km/s at 30 km depth (Moho) along the refraction line, with a nearly constant S-wave velocity around 3.8 km/s. These velocities likely represent a gabbroic and hornblende granulite composition for the lower crust. This typical (but somewhat thin) Precambrian crustal velocity structure in southwestern Greenland shows no evidence for a high-velocity, lower crustal, underplated layer caused by the Mesozoic opening of the Labrador Sea. Article in Journal/Newspaper Greenland Labrador Sea Canadian Science Publishing Canadian Journal of Earth Sciences 29 2 301 313 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
The velocity structure of the continental crust on the outer shelf of southwestern Greenland is determined from dense wide-angle reflection–refraction data obtained with large air-gun sources and ocean bottom seismometers along a 230 km seismic line. This line crosses the geological boundary between the Archean block and the Ketilidian mobile belt. Although the data have high noise levels, P- and S-wave arrivals from within the upper, intermediate, and lower crust, and at the Moho boundary, can be consistently identified and correlated with one-dimensional WKBJ synthetic seismograms. In the Archean, P- and S-wave velocities in the upper crust are 6.0 and 3.4 km/s, while in the intermediate crust they are 6.4 and 3.6 km/s. These velocities match for the upper crust a quartz–feldspar gneiss composition and for the intermediate crust an amphibolitized pyroxene granulite. In the Ketilidian mobile belt, P- and S-wave velocities are 5.6 and 3.3 km/s for the upper crust and 6.3 and 3.6 km/s for the intermediate crust. These velocities may represent quartz granite in the upper crust and granite and granitic gneiss in the intermediate crust. The upper crust is ~5 km thick in the Archean block and the Ketilidian mobile belt, and thickens to ~9 km in the southern part of the Archean. This velocity structure supports a Precambrian collisional mechanism between the Archean block and Ketilidian mobile belt. The lower crust has a small vertical velocity gradient from 6.6 km/s at 15 km depth to 6.9 km/s at 30 km depth (Moho) along the refraction line, with a nearly constant S-wave velocity around 3.8 km/s. These velocities likely represent a gabbroic and hornblende granulite composition for the lower crust. This typical (but somewhat thin) Precambrian crustal velocity structure in southwestern Greenland shows no evidence for a high-velocity, lower crustal, underplated layer caused by the Mesozoic opening of the Labrador Sea. |
format |
Article in Journal/Newspaper |
author |
Chian, Deping Louden, Keith |
spellingShingle |
Chian, Deping Louden, Keith The structure of Archean–Ketilidian crust along the continental shelf of southwestern Greenland from a seismic refraction profile |
author_facet |
Chian, Deping Louden, Keith |
author_sort |
Chian, Deping |
title |
The structure of Archean–Ketilidian crust along the continental shelf of southwestern Greenland from a seismic refraction profile |
title_short |
The structure of Archean–Ketilidian crust along the continental shelf of southwestern Greenland from a seismic refraction profile |
title_full |
The structure of Archean–Ketilidian crust along the continental shelf of southwestern Greenland from a seismic refraction profile |
title_fullStr |
The structure of Archean–Ketilidian crust along the continental shelf of southwestern Greenland from a seismic refraction profile |
title_full_unstemmed |
The structure of Archean–Ketilidian crust along the continental shelf of southwestern Greenland from a seismic refraction profile |
title_sort |
structure of archean–ketilidian crust along the continental shelf of southwestern greenland from a seismic refraction profile |
publisher |
Canadian Science Publishing |
publishDate |
1992 |
url |
http://dx.doi.org/10.1139/e92-027 http://www.nrcresearchpress.com/doi/pdf/10.1139/e92-027 |
genre |
Greenland Labrador Sea |
genre_facet |
Greenland Labrador Sea |
op_source |
Canadian Journal of Earth Sciences volume 29, issue 2, page 301-313 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e92-027 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
29 |
container_issue |
2 |
container_start_page |
301 |
op_container_end_page |
313 |
_version_ |
1810446882679291904 |