Sill and lava geochemistry of the mid-Norway and NE Greenland conjugate margins
This paper presents major, trace-elements, and Sr-Nd isotopes for two prominent sills formed during the opening of the North Atlantic, sampled by the Utgard borehole (6607/5-2) in the VOring Plateau. The Utgard sills are compared to opening-related lavas recovered from ODP Leg 104 Hole 642E farther...
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ftuniaarhuspubl:oai:pure.atira.dk:publications/ba68dd94-c393-4649-8d90-43f256de19e9 2024-04-28T08:21:21+00:00 Sill and lava geochemistry of the mid-Norway and NE Greenland conjugate margins Neumann, Else-Ragnhild Svensen, Henrik Tegner, Christian Planke, Sverre Thirlwall, Matthew Jarvis, Kym E. 2013 https://pure.au.dk/portal/en/publications/ba68dd94-c393-4649-8d90-43f256de19e9 https://doi.org/10.1002/ggge.20224 eng eng https://pure.au.dk/portal/en/publications/ba68dd94-c393-4649-8d90-43f256de19e9 info:eu-repo/semantics/restrictedAccess Neumann , E-R , Svensen , H , Tegner , C , Planke , S , Thirlwall , M & Jarvis , K E 2013 , ' Sill and lava geochemistry of the mid-Norway and NE Greenland conjugate margins ' , Geochemistry, Geophysics, Geosystems , vol. 14 , no. 9 , pp. 3666-3690 . https://doi.org/10.1002/ggge.20224 article 2013 ftuniaarhuspubl https://doi.org/10.1002/ggge.20224 2024-04-10T23:41:05Z This paper presents major, trace-elements, and Sr-Nd isotopes for two prominent sills formed during the opening of the North Atlantic, sampled by the Utgard borehole (6607/5-2) in the VOring Plateau. The Utgard sills are compared to opening-related lavas recovered from ODP Leg 104 Hole 642E farther west on the VOring Plateau and on the NE Greenland conjugate margin. The Utgard sills (3.6-5.9 wt % MgO) are enriched in strongly relative to moderately incompatible trace elements and have Sr-87/Sr-86 and Nd-143/Nd-144 ratios of 0.70380-70387 and 0.51292-0.51293, respectively, in the Upper Utgard Sill, and 0.70303-0.70306 and 0.51297-0.51299 in the Lower Sill. Alteration is minor. The Utgard melts originated by partial melting of an asthenospheric, depleted mantle source (DMM or Iceland Rift Zone, IRZ, type) with chemical characteristics similar to the source that gave rise to NE Greenland lavas. The Utgard magmas underwent extensive fractional crystallization in the lower crust (Upper Sill: >70%; Lower Sill: >55%) with removal mainly of olivine and pyroxenes, accompanied by 1% assimilation of crustal melts. This crystallization formed significant masses of dense cumulates (approximate to 3.25 g/cm(3)) (underplating). Assuming an areal extent similar to that of the two sills, we estimate a composite layer of ultramafic cumulates mixed with less dense country rocks to be >320 m thick beneath the two Utgard sills and >8.8 km beneath the thickest part of the VOring Plateau lavas. Opening-related cumulates may thus account for a significant part of the lower crustal high-velocity, high-density bodies (average density 3.1 g/cm(3)) along the Norwegian margin. Article in Journal/Newspaper Greenland Iceland North Atlantic Aarhus University: Research Geochemistry, Geophysics, Geosystems 14 9 3666 3690 |
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Open Polar |
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Aarhus University: Research |
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ftuniaarhuspubl |
language |
English |
description |
This paper presents major, trace-elements, and Sr-Nd isotopes for two prominent sills formed during the opening of the North Atlantic, sampled by the Utgard borehole (6607/5-2) in the VOring Plateau. The Utgard sills are compared to opening-related lavas recovered from ODP Leg 104 Hole 642E farther west on the VOring Plateau and on the NE Greenland conjugate margin. The Utgard sills (3.6-5.9 wt % MgO) are enriched in strongly relative to moderately incompatible trace elements and have Sr-87/Sr-86 and Nd-143/Nd-144 ratios of 0.70380-70387 and 0.51292-0.51293, respectively, in the Upper Utgard Sill, and 0.70303-0.70306 and 0.51297-0.51299 in the Lower Sill. Alteration is minor. The Utgard melts originated by partial melting of an asthenospheric, depleted mantle source (DMM or Iceland Rift Zone, IRZ, type) with chemical characteristics similar to the source that gave rise to NE Greenland lavas. The Utgard magmas underwent extensive fractional crystallization in the lower crust (Upper Sill: >70%; Lower Sill: >55%) with removal mainly of olivine and pyroxenes, accompanied by 1% assimilation of crustal melts. This crystallization formed significant masses of dense cumulates (approximate to 3.25 g/cm(3)) (underplating). Assuming an areal extent similar to that of the two sills, we estimate a composite layer of ultramafic cumulates mixed with less dense country rocks to be >320 m thick beneath the two Utgard sills and >8.8 km beneath the thickest part of the VOring Plateau lavas. Opening-related cumulates may thus account for a significant part of the lower crustal high-velocity, high-density bodies (average density 3.1 g/cm(3)) along the Norwegian margin. |
format |
Article in Journal/Newspaper |
author |
Neumann, Else-Ragnhild Svensen, Henrik Tegner, Christian Planke, Sverre Thirlwall, Matthew Jarvis, Kym E. |
spellingShingle |
Neumann, Else-Ragnhild Svensen, Henrik Tegner, Christian Planke, Sverre Thirlwall, Matthew Jarvis, Kym E. Sill and lava geochemistry of the mid-Norway and NE Greenland conjugate margins |
author_facet |
Neumann, Else-Ragnhild Svensen, Henrik Tegner, Christian Planke, Sverre Thirlwall, Matthew Jarvis, Kym E. |
author_sort |
Neumann, Else-Ragnhild |
title |
Sill and lava geochemistry of the mid-Norway and NE Greenland conjugate margins |
title_short |
Sill and lava geochemistry of the mid-Norway and NE Greenland conjugate margins |
title_full |
Sill and lava geochemistry of the mid-Norway and NE Greenland conjugate margins |
title_fullStr |
Sill and lava geochemistry of the mid-Norway and NE Greenland conjugate margins |
title_full_unstemmed |
Sill and lava geochemistry of the mid-Norway and NE Greenland conjugate margins |
title_sort |
sill and lava geochemistry of the mid-norway and ne greenland conjugate margins |
publishDate |
2013 |
url |
https://pure.au.dk/portal/en/publications/ba68dd94-c393-4649-8d90-43f256de19e9 https://doi.org/10.1002/ggge.20224 |
genre |
Greenland Iceland North Atlantic |
genre_facet |
Greenland Iceland North Atlantic |
op_source |
Neumann , E-R , Svensen , H , Tegner , C , Planke , S , Thirlwall , M & Jarvis , K E 2013 , ' Sill and lava geochemistry of the mid-Norway and NE Greenland conjugate margins ' , Geochemistry, Geophysics, Geosystems , vol. 14 , no. 9 , pp. 3666-3690 . https://doi.org/10.1002/ggge.20224 |
op_relation |
https://pure.au.dk/portal/en/publications/ba68dd94-c393-4649-8d90-43f256de19e9 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1002/ggge.20224 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
14 |
container_issue |
9 |
container_start_page |
3666 |
op_container_end_page |
3690 |
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1797583730828640256 |