Crustal structures of the Boreas Basin and the Knipovich Ridge, North Atlantic
The Boreas Basin is located in the Norwegian-Greenland Sea between Northeast Greenland and Svalbard. Towards the east, it is bounded by the ultraslow mid-ocean Knipovich Ridge. Here, we present a 340-km-long seismic refraction line acquired during the expedition ARK-XXIV/3 of research vessel Polarst...
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fthighwire:oai:open-archive.highwire.org:gji:193/3/1399 2023-05-15T16:27:36+02:00 Crustal structures of the Boreas Basin and the Knipovich Ridge, North Atlantic Hermann, Tobias Jokat, Wilfried 2013-06-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/193/3/1399 https://doi.org/10.1093/gji/ggt048 en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/193/3/1399 http://dx.doi.org/10.1093/gji/ggt048 Copyright (C) 2013, Oxford University Press Marine geosciences and applied geophysics TEXT 2013 fthighwire https://doi.org/10.1093/gji/ggt048 2015-02-28T20:54:25Z The Boreas Basin is located in the Norwegian-Greenland Sea between Northeast Greenland and Svalbard. Towards the east, it is bounded by the ultraslow mid-ocean Knipovich Ridge. Here, we present a 340-km-long seismic refraction line acquired during the expedition ARK-XXIV/3 of research vessel Polarstern in 2009, using 18 ocean bottom seismometers. It crosses the central Boreas Basin from the Knipovich Ridge to the Northeast Greenland margin. Thus, the line provides the first reliable crustal structure information of this basin. In addition, the gravity data acquired parallel to the seismic refraction line are used to calculate a 2.5-D gravity model. The P -wave velocity model shows an unusual ∼3-km-thin oceanic crust with seismic velocities less than 6.3 km s−1, indicating the absence of a significant oceanic layer 3. Mantle velocities vary between 7.5 km s−1 in the uppermost mantle and 8.0 km s−1 at approximately 15 km depth. The low velocities within the upper mantle may be explained by 13 per cent serpentinisation, which is negligible at about 15 km depth. Furthermore, the S -wave velocity model shows low V p / V s ratios in the mantle, indicating a highly serpentinised mantle at shallow depths. The gravity model has crustal densities between 2.3 and 2.9 g cm−3, which also point towards the absence of a significant thick oceanic layer 3. The results of our seismic refraction line and other geophysical data indicate that the entire Boreas Basin opened at ultraslow spreading rates since at least ∼28 Ma. No evidence for an extinct spreading ridge in the centre of the Boreas Basin was found. Text Greenland Greenland Sea North Atlantic Svalbard HighWire Press (Stanford University) Boreas ENVELOPE(-3.933,-3.933,-71.300,-71.300) Boreas Basin ENVELOPE(1.000,1.000,77.500,77.500) Greenland Knipovich Ridge ENVELOPE(7.074,7.074,75.712,75.712) Svalbard Geophysical Journal International 193 3 1399 1414 |
institution |
Open Polar |
collection |
HighWire Press (Stanford University) |
op_collection_id |
fthighwire |
language |
English |
topic |
Marine geosciences and applied geophysics |
spellingShingle |
Marine geosciences and applied geophysics Hermann, Tobias Jokat, Wilfried Crustal structures of the Boreas Basin and the Knipovich Ridge, North Atlantic |
topic_facet |
Marine geosciences and applied geophysics |
description |
The Boreas Basin is located in the Norwegian-Greenland Sea between Northeast Greenland and Svalbard. Towards the east, it is bounded by the ultraslow mid-ocean Knipovich Ridge. Here, we present a 340-km-long seismic refraction line acquired during the expedition ARK-XXIV/3 of research vessel Polarstern in 2009, using 18 ocean bottom seismometers. It crosses the central Boreas Basin from the Knipovich Ridge to the Northeast Greenland margin. Thus, the line provides the first reliable crustal structure information of this basin. In addition, the gravity data acquired parallel to the seismic refraction line are used to calculate a 2.5-D gravity model. The P -wave velocity model shows an unusual ∼3-km-thin oceanic crust with seismic velocities less than 6.3 km s−1, indicating the absence of a significant oceanic layer 3. Mantle velocities vary between 7.5 km s−1 in the uppermost mantle and 8.0 km s−1 at approximately 15 km depth. The low velocities within the upper mantle may be explained by 13 per cent serpentinisation, which is negligible at about 15 km depth. Furthermore, the S -wave velocity model shows low V p / V s ratios in the mantle, indicating a highly serpentinised mantle at shallow depths. The gravity model has crustal densities between 2.3 and 2.9 g cm−3, which also point towards the absence of a significant thick oceanic layer 3. The results of our seismic refraction line and other geophysical data indicate that the entire Boreas Basin opened at ultraslow spreading rates since at least ∼28 Ma. No evidence for an extinct spreading ridge in the centre of the Boreas Basin was found. |
format |
Text |
author |
Hermann, Tobias Jokat, Wilfried |
author_facet |
Hermann, Tobias Jokat, Wilfried |
author_sort |
Hermann, Tobias |
title |
Crustal structures of the Boreas Basin and the Knipovich Ridge, North Atlantic |
title_short |
Crustal structures of the Boreas Basin and the Knipovich Ridge, North Atlantic |
title_full |
Crustal structures of the Boreas Basin and the Knipovich Ridge, North Atlantic |
title_fullStr |
Crustal structures of the Boreas Basin and the Knipovich Ridge, North Atlantic |
title_full_unstemmed |
Crustal structures of the Boreas Basin and the Knipovich Ridge, North Atlantic |
title_sort |
crustal structures of the boreas basin and the knipovich ridge, north atlantic |
publisher |
Oxford University Press |
publishDate |
2013 |
url |
http://gji.oxfordjournals.org/cgi/content/short/193/3/1399 https://doi.org/10.1093/gji/ggt048 |
long_lat |
ENVELOPE(-3.933,-3.933,-71.300,-71.300) ENVELOPE(1.000,1.000,77.500,77.500) ENVELOPE(7.074,7.074,75.712,75.712) |
geographic |
Boreas Boreas Basin Greenland Knipovich Ridge Svalbard |
geographic_facet |
Boreas Boreas Basin Greenland Knipovich Ridge Svalbard |
genre |
Greenland Greenland Sea North Atlantic Svalbard |
genre_facet |
Greenland Greenland Sea North Atlantic Svalbard |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/193/3/1399 http://dx.doi.org/10.1093/gji/ggt048 |
op_rights |
Copyright (C) 2013, Oxford University Press |
op_doi |
https://doi.org/10.1093/gji/ggt048 |
container_title |
Geophysical Journal International |
container_volume |
193 |
container_issue |
3 |
container_start_page |
1399 |
op_container_end_page |
1414 |
_version_ |
1766017001207103488 |