Crustal structure of the Boreas Basin formed at ultraslow spreading Knipovich Ridge – Northern North Atlantic
The Boreas Basin is located in Norwegian Greenland Sea bordered by the Greenland Fracture Zone in the south and the Hovgard Ridge in the north, respectively. In the east it adjoins the ultraslow mid-ocean Knipovich Ridge. Previous seismic reflection studies in the Boreas Basin have shown that the ba...
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ftawi:oai:epic.awi.de:25616 2023-05-15T16:28:29+02:00 Crustal structure of the Boreas Basin formed at ultraslow spreading Knipovich Ridge – Northern North Atlantic Hermann, Tobias Jokat, Wilfried 2012-04-26 https://epic.awi.de/id/eprint/25616/ https://hdl.handle.net/10013/epic.38990 unknown Hermann, T. and Jokat, W. orcid:0000-0002-7793-5854 (2012) Crustal structure of the Boreas Basin formed at ultraslow spreading Knipovich Ridge – Northern North Atlantic , EGU 2012, Vienna, Austria, 22 April 2012 - 27 April 2012 . hdl:10013/epic.38990 EPIC3EGU 2012, Vienna, Austria, 2012-04-22-2012-04-27 Conference notRev 2012 ftawi 2021-12-24T15:35:27Z The Boreas Basin is located in Norwegian Greenland Sea bordered by the Greenland Fracture Zone in the south and the Hovgard Ridge in the north, respectively. In the east it adjoins the ultraslow mid-ocean Knipovich Ridge. Previous seismic reflection studies in the Boreas Basin have shown that the basement topography has a roughness, which is typical for ultraslow spreading ridges. This observation supports assumptions that the basin was formed at ultraslow spreading rates during its entire geological history. However, the detailed crustal structure remained unresolved. In summer 2009 new seismic refraction data were acquired in the Boreas Basin during the expedition ARK-XXIV/3 with the research vessel Polarstern. The deep seismic sounding line has a length of 340 km. Forward modelling of the data of 18 ocean bottom seismometers deployed along the NW-SE trending profile reveal an unusual 3.2 km thin oceanic crust. The crustal model is further constrained by S-wave and 2D gravity modelling. The P-wave velocity model shows a layered oceanic crust without oceanic layer 3 and with velocities less than 6.3 km/s except beneath a nearly 2000 m high seamount. Beneath the seamount velocities of up to 6.7 km/s were observed. The mantle velocities range between 7.5 km/s in the uppermost mantle and 8.0 km/s in almost 15 km depth. A serpentinisation of approximately 13% in the uppermost mantle decreasing downwards can explain the low mantle velocities. In summary, the transect confirms earlier models that the entire Boreas Basin was formed at ultraslow spreading rates. Indications for this are the basement roughness and the overall thin oceanic crust. Both observations are typical for ultraslow spreading systems. Conference Object Greenland Greenland Sea North Atlantic Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Greenland Boreas ENVELOPE(-3.933,-3.933,-71.300,-71.300) Knipovich Ridge ENVELOPE(7.074,7.074,75.712,75.712) Boreas Basin ENVELOPE(1.000,1.000,77.500,77.500) Greenland Fracture Zone ENVELOPE(0.500,0.500,75.500,75.500) |
institution |
Open Polar |
collection |
Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
The Boreas Basin is located in Norwegian Greenland Sea bordered by the Greenland Fracture Zone in the south and the Hovgard Ridge in the north, respectively. In the east it adjoins the ultraslow mid-ocean Knipovich Ridge. Previous seismic reflection studies in the Boreas Basin have shown that the basement topography has a roughness, which is typical for ultraslow spreading ridges. This observation supports assumptions that the basin was formed at ultraslow spreading rates during its entire geological history. However, the detailed crustal structure remained unresolved. In summer 2009 new seismic refraction data were acquired in the Boreas Basin during the expedition ARK-XXIV/3 with the research vessel Polarstern. The deep seismic sounding line has a length of 340 km. Forward modelling of the data of 18 ocean bottom seismometers deployed along the NW-SE trending profile reveal an unusual 3.2 km thin oceanic crust. The crustal model is further constrained by S-wave and 2D gravity modelling. The P-wave velocity model shows a layered oceanic crust without oceanic layer 3 and with velocities less than 6.3 km/s except beneath a nearly 2000 m high seamount. Beneath the seamount velocities of up to 6.7 km/s were observed. The mantle velocities range between 7.5 km/s in the uppermost mantle and 8.0 km/s in almost 15 km depth. A serpentinisation of approximately 13% in the uppermost mantle decreasing downwards can explain the low mantle velocities. In summary, the transect confirms earlier models that the entire Boreas Basin was formed at ultraslow spreading rates. Indications for this are the basement roughness and the overall thin oceanic crust. Both observations are typical for ultraslow spreading systems. |
format |
Conference Object |
author |
Hermann, Tobias Jokat, Wilfried |
spellingShingle |
Hermann, Tobias Jokat, Wilfried Crustal structure of the Boreas Basin formed at ultraslow spreading Knipovich Ridge – Northern North Atlantic |
author_facet |
Hermann, Tobias Jokat, Wilfried |
author_sort |
Hermann, Tobias |
title |
Crustal structure of the Boreas Basin formed at ultraslow spreading Knipovich Ridge – Northern North Atlantic |
title_short |
Crustal structure of the Boreas Basin formed at ultraslow spreading Knipovich Ridge – Northern North Atlantic |
title_full |
Crustal structure of the Boreas Basin formed at ultraslow spreading Knipovich Ridge – Northern North Atlantic |
title_fullStr |
Crustal structure of the Boreas Basin formed at ultraslow spreading Knipovich Ridge – Northern North Atlantic |
title_full_unstemmed |
Crustal structure of the Boreas Basin formed at ultraslow spreading Knipovich Ridge – Northern North Atlantic |
title_sort |
crustal structure of the boreas basin formed at ultraslow spreading knipovich ridge – northern north atlantic |
publishDate |
2012 |
url |
https://epic.awi.de/id/eprint/25616/ https://hdl.handle.net/10013/epic.38990 |
long_lat |
ENVELOPE(-3.933,-3.933,-71.300,-71.300) ENVELOPE(7.074,7.074,75.712,75.712) ENVELOPE(1.000,1.000,77.500,77.500) ENVELOPE(0.500,0.500,75.500,75.500) |
geographic |
Greenland Boreas Knipovich Ridge Boreas Basin Greenland Fracture Zone |
geographic_facet |
Greenland Boreas Knipovich Ridge Boreas Basin Greenland Fracture Zone |
genre |
Greenland Greenland Sea North Atlantic |
genre_facet |
Greenland Greenland Sea North Atlantic |
op_source |
EPIC3EGU 2012, Vienna, Austria, 2012-04-22-2012-04-27 |
op_relation |
Hermann, T. and Jokat, W. orcid:0000-0002-7793-5854 (2012) Crustal structure of the Boreas Basin formed at ultraslow spreading Knipovich Ridge – Northern North Atlantic , EGU 2012, Vienna, Austria, 22 April 2012 - 27 April 2012 . hdl:10013/epic.38990 |
_version_ |
1766018134082322432 |