Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths
The Lewisian Gneiss Complex of NW Scotland represents the eastern margin of the North Atlantic Craton.It comprises mid-late Archaean tonalite-trondhjemite-granodiorite gneisses that were metamorphosedand deformed during the Late-Archaean and Palaeoproterozoic. A major swarm of mafic-ultramafic dykes...
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Language: | English |
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Elsevier
2014
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Online Access: | https://orca.cardiff.ac.uk/id/eprint/60883/ https://doi.org/10.1016/j.precamres.2014.05.026 https://orca.cardiff.ac.uk/id/eprint/60883/1/Hughes%20et%20al.%202014%20Enriched%20lithospheric%20mantle%20keel%20below%20the%20Scottish%20margin%20of%20the%20North%20Atlantic%20Craton-1.pdf |
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Cardiff University: ORCA (Online Research @ Cardiff) |
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English |
description |
The Lewisian Gneiss Complex of NW Scotland represents the eastern margin of the North Atlantic Craton.It comprises mid-late Archaean tonalite-trondhjemite-granodiorite gneisses that were metamorphosedand deformed during the Late-Archaean and Palaeoproterozoic. A major swarm of mafic-ultramafic dykes,the Scourie Dyke Swarm, was intruded at ca. 2.4–2.3 Ga during a period of extension that can be correlatedacross the North Atlantic Craton. The majority of dykes are doleritic, with volumetrically minor picriteand olivine gabbro suites.New major and trace element geochemical data and Re-Os isotopes indicate that the Scourie DykeSwarm was not solely derived from a ‘typical’ asthenospheric mantle source region. The geochemicalsignatures of the dykes show significant negative Nb, Ta and Ti anomalies, coupled with enrichment in Th,Light Rare Earth Elements and other large ion lithophile elements. These features cannot be reproducedby simple contamination of asthenospheric sources with Lewisian granulite-facies crust. Instead they area feature of the mantle source that produced the Scourie Dykes and may have developed during Archaeansubduction episodes.Spinel lherzolite mantle xenoliths from the Isle of Lewis offer direct insight into the lithospheric mantlebelow this region. They display similar geochemical ‘enrichments’ and ‘depletions’ observed in the ScourieDykes and the magma source is thus considered to reside primarily in the sub-continental lithosphericmantle (SCLM), with some potential contribution from asthenospheric melts. Platinum Group Elementgeochemistry and trace element modelling indicate that the dolerite dykes were formed by moderate(<15%) partial melting of the source, whilst higher degrees of partial melting led to the formation ofpicritic and olivine gabbro suites. Magma production was triggered by significant crustal and lithosphericextension, causing both asthenospheric and substantial lithospheric melting. |
format |
Article in Journal/Newspaper |
author |
Hughes, Hannah S. R. McDonald, Iain Goodenough, Kathryn M. Ciborowski, Thomas Kerr, Andrew Craig Davies, Joshua H.F.L. Selby, David |
spellingShingle |
Hughes, Hannah S. R. McDonald, Iain Goodenough, Kathryn M. Ciborowski, Thomas Kerr, Andrew Craig Davies, Joshua H.F.L. Selby, David Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths |
author_facet |
Hughes, Hannah S. R. McDonald, Iain Goodenough, Kathryn M. Ciborowski, Thomas Kerr, Andrew Craig Davies, Joshua H.F.L. Selby, David |
author_sort |
Hughes, Hannah S. R. |
title |
Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths |
title_short |
Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths |
title_full |
Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths |
title_fullStr |
Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths |
title_full_unstemmed |
Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths |
title_sort |
enriched lithospheric mantle keel below the scottish margin of the north atlantic craton: evidence from the palaeoproterozoic scourie dyke swarm and mantle xenoliths |
publisher |
Elsevier |
publishDate |
2014 |
url |
https://orca.cardiff.ac.uk/id/eprint/60883/ https://doi.org/10.1016/j.precamres.2014.05.026 https://orca.cardiff.ac.uk/id/eprint/60883/1/Hughes%20et%20al.%202014%20Enriched%20lithospheric%20mantle%20keel%20below%20the%20Scottish%20margin%20of%20the%20North%20Atlantic%20Craton-1.pdf |
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North Atlantic |
genre_facet |
North Atlantic |
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https://orca.cardiff.ac.uk/id/eprint/60883/1/Hughes%20et%20al.%202014%20Enriched%20lithospheric%20mantle%20keel%20below%20the%20Scottish%20margin%20of%20the%20North%20Atlantic%20Craton-1.pdf Hughes, Hannah S. R. https://orca.cardiff.ac.uk/view/cardiffauthors/A295081O.html, McDonald, Iain https://orca.cardiff.ac.uk/view/cardiffauthors/A0179053.html orcid:0000-0001-9066-7244 orcid:0000-0001-9066-7244, Goodenough, Kathryn M., Ciborowski, Thomas https://orca.cardiff.ac.uk/view/cardiffauthors/A155764U.html, Kerr, Andrew Craig https://orca.cardiff.ac.uk/view/cardiffauthors/A0488436.html orcid:0000-0001-5569-4730 orcid:0000-0001-5569-4730, Davies, Joshua H.F.L. and Selby, David 2014. Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths. Precambrian Research 250 , pp. 97-126. 10.1016/j.precamres.2014.05.026 https://doi.org/10.1016/j.precamres.2014.05.026 file https://orca.cardiff.ac.uk/60883/1/Hughes%20et%20al.%202014%20Enriched%20lithospheric%20mantle%20keel%20below%20the%20Scottish%20margin%20of%20the%20North%20Atlantic%20Craton-1.pdf doi:10.1016/j.precamres.2014.05.026 |
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https://doi.org/10.1016/j.precamres.2014.05.026 |
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ftunivcardiff:oai:https://orca.cardiff.ac.uk:60883 2023-05-15T17:29:42+02:00 Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths Hughes, Hannah S. R. McDonald, Iain Goodenough, Kathryn M. Ciborowski, Thomas Kerr, Andrew Craig Davies, Joshua H.F.L. Selby, David 2014-09-01 application/pdf https://orca.cardiff.ac.uk/id/eprint/60883/ https://doi.org/10.1016/j.precamres.2014.05.026 https://orca.cardiff.ac.uk/id/eprint/60883/1/Hughes%20et%20al.%202014%20Enriched%20lithospheric%20mantle%20keel%20below%20the%20Scottish%20margin%20of%20the%20North%20Atlantic%20Craton-1.pdf en eng Elsevier https://orca.cardiff.ac.uk/id/eprint/60883/1/Hughes%20et%20al.%202014%20Enriched%20lithospheric%20mantle%20keel%20below%20the%20Scottish%20margin%20of%20the%20North%20Atlantic%20Craton-1.pdf Hughes, Hannah S. R. https://orca.cardiff.ac.uk/view/cardiffauthors/A295081O.html, McDonald, Iain https://orca.cardiff.ac.uk/view/cardiffauthors/A0179053.html orcid:0000-0001-9066-7244 orcid:0000-0001-9066-7244, Goodenough, Kathryn M., Ciborowski, Thomas https://orca.cardiff.ac.uk/view/cardiffauthors/A155764U.html, Kerr, Andrew Craig https://orca.cardiff.ac.uk/view/cardiffauthors/A0488436.html orcid:0000-0001-5569-4730 orcid:0000-0001-5569-4730, Davies, Joshua H.F.L. and Selby, David 2014. Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths. Precambrian Research 250 , pp. 97-126. 10.1016/j.precamres.2014.05.026 https://doi.org/10.1016/j.precamres.2014.05.026 file https://orca.cardiff.ac.uk/60883/1/Hughes%20et%20al.%202014%20Enriched%20lithospheric%20mantle%20keel%20below%20the%20Scottish%20margin%20of%20the%20North%20Atlantic%20Craton-1.pdf doi:10.1016/j.precamres.2014.05.026 cc_by CC-BY Article PeerReviewed 2014 ftunivcardiff https://doi.org/10.1016/j.precamres.2014.05.026 2022-10-27T22:39:05Z The Lewisian Gneiss Complex of NW Scotland represents the eastern margin of the North Atlantic Craton.It comprises mid-late Archaean tonalite-trondhjemite-granodiorite gneisses that were metamorphosedand deformed during the Late-Archaean and Palaeoproterozoic. A major swarm of mafic-ultramafic dykes,the Scourie Dyke Swarm, was intruded at ca. 2.4–2.3 Ga during a period of extension that can be correlatedacross the North Atlantic Craton. The majority of dykes are doleritic, with volumetrically minor picriteand olivine gabbro suites.New major and trace element geochemical data and Re-Os isotopes indicate that the Scourie DykeSwarm was not solely derived from a ‘typical’ asthenospheric mantle source region. The geochemicalsignatures of the dykes show significant negative Nb, Ta and Ti anomalies, coupled with enrichment in Th,Light Rare Earth Elements and other large ion lithophile elements. These features cannot be reproducedby simple contamination of asthenospheric sources with Lewisian granulite-facies crust. Instead they area feature of the mantle source that produced the Scourie Dykes and may have developed during Archaeansubduction episodes.Spinel lherzolite mantle xenoliths from the Isle of Lewis offer direct insight into the lithospheric mantlebelow this region. They display similar geochemical ‘enrichments’ and ‘depletions’ observed in the ScourieDykes and the magma source is thus considered to reside primarily in the sub-continental lithosphericmantle (SCLM), with some potential contribution from asthenospheric melts. Platinum Group Elementgeochemistry and trace element modelling indicate that the dolerite dykes were formed by moderate(<15%) partial melting of the source, whilst higher degrees of partial melting led to the formation ofpicritic and olivine gabbro suites. Magma production was triggered by significant crustal and lithosphericextension, causing both asthenospheric and substantial lithospheric melting. Article in Journal/Newspaper North Atlantic Cardiff University: ORCA (Online Research @ Cardiff) Precambrian Research 250 97 126 |