First evidence for Neoproterozoic rocks offshore South-East Greenland
Meta-sedimentary rocks recovered beneath Palaeogene basalts near the base of Ocean Drilling Program (ODP) Leg 152-917A offshore South-East Greenland were thought to be of Late Cretaceous age. This interpretation, however, has several inconsistencies as it requires a tectono-metamorphic event during...
Published in: | Geological Magazine |
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2022
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Online Access: | https://curis.ku.dk/portal/da/publications/first-evidence-for-neoproterozoic-rocks-offshore-southeast-greenland(207ca319-feea-417b-b89b-1d8172bd9ce5).html https://doi.org/10.1017/S0016756821001400 |
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ftcopenhagenunip:oai:pure.atira.dk:publications/207ca319-feea-417b-b89b-1d8172bd9ce5 2024-04-21T08:01:13+00:00 First evidence for Neoproterozoic rocks offshore South-East Greenland Guarnieri, Pierpaolo Storey, Michael Thomsen, Tonny B. Heredia, Benjamin Dominguez Malkki, Sebastian Næsby 2022 https://curis.ku.dk/portal/da/publications/first-evidence-for-neoproterozoic-rocks-offshore-southeast-greenland(207ca319-feea-417b-b89b-1d8172bd9ce5).html https://doi.org/10.1017/S0016756821001400 eng eng info:eu-repo/semantics/closedAccess Guarnieri , P , Storey , M , Thomsen , T B , Heredia , B D & Malkki , S N 2022 , ' First evidence for Neoproterozoic rocks offshore South-East Greenland ' , Geological Magazine , vol. 159 , no. 5 , pp. 782-796 . https://doi.org/10.1017/S0016756821001400 Ar/Ar-Geochronology Automated quantitative mineral mapping Neoproterozoic South-East Greenland U/Pb-Geochronology article 2022 ftcopenhagenunip https://doi.org/10.1017/S0016756821001400 2024-04-11T00:22:45Z Meta-sedimentary rocks recovered beneath Palaeogene basalts near the base of Ocean Drilling Program (ODP) Leg 152-917A offshore South-East Greenland were thought to be of Late Cretaceous age. This interpretation, however, has several inconsistencies as it requires a tectono-metamorphic event during the Cretaceous not recognized in the North Atlantic region, and the presence of a wide Mesozoic sedimentary basin that extended from SE-Greenland to the Rockall Plateau, for which there is currently no evidence. Here, we report a Neoproterozoic U/Pb apatite age of 905 ± 21 Ma and a younger 40Ar/39Ar isochron whole-rock age of 820 ± 40 Ma for an altered tuff layer that occurs in the upper part of the meta-volcaniclastic sequence recovered from hole 917A. The 40Ar/39Ar step-heating ages on biotite and whole-rock mini-cores from deeper in hole 917A yielded Palaeoproterozic dates that cluster around 1950 to 1850 Ma, pointing toward a Palaeoproterozoic source. The U/Pb apatite date is interpreted as the eruption age of the tuff layer, whereas the younger whole-rock 40Ar/39Ar age is consistent with low-Temperature greenschist alteration of volcanic glass and secondary mineral growth during sedimentary burial in an extensional regime. The c. 905 Ma age for the tuff provides the first evidence for Neoproterozoic rocks offshore South-East Greenland and suggests a correlation between this sequence and the Torridon Group in the Hebridean Foreland of the Scottish Caledonides. The calc-Alkaline nature of the volcaniclastic rocks and the age of the tuff layer point toward a source area with arc-magmatism related to the Renlandian event of the Valhalla Orogeny. Article in Journal/Newspaper East Greenland Greenland North Atlantic University of Copenhagen: Research Geological Magazine 159 5 782 796 |
institution |
Open Polar |
collection |
University of Copenhagen: Research |
op_collection_id |
ftcopenhagenunip |
language |
English |
topic |
Ar/Ar-Geochronology Automated quantitative mineral mapping Neoproterozoic South-East Greenland U/Pb-Geochronology |
spellingShingle |
Ar/Ar-Geochronology Automated quantitative mineral mapping Neoproterozoic South-East Greenland U/Pb-Geochronology Guarnieri, Pierpaolo Storey, Michael Thomsen, Tonny B. Heredia, Benjamin Dominguez Malkki, Sebastian Næsby First evidence for Neoproterozoic rocks offshore South-East Greenland |
topic_facet |
Ar/Ar-Geochronology Automated quantitative mineral mapping Neoproterozoic South-East Greenland U/Pb-Geochronology |
description |
Meta-sedimentary rocks recovered beneath Palaeogene basalts near the base of Ocean Drilling Program (ODP) Leg 152-917A offshore South-East Greenland were thought to be of Late Cretaceous age. This interpretation, however, has several inconsistencies as it requires a tectono-metamorphic event during the Cretaceous not recognized in the North Atlantic region, and the presence of a wide Mesozoic sedimentary basin that extended from SE-Greenland to the Rockall Plateau, for which there is currently no evidence. Here, we report a Neoproterozoic U/Pb apatite age of 905 ± 21 Ma and a younger 40Ar/39Ar isochron whole-rock age of 820 ± 40 Ma for an altered tuff layer that occurs in the upper part of the meta-volcaniclastic sequence recovered from hole 917A. The 40Ar/39Ar step-heating ages on biotite and whole-rock mini-cores from deeper in hole 917A yielded Palaeoproterozic dates that cluster around 1950 to 1850 Ma, pointing toward a Palaeoproterozoic source. The U/Pb apatite date is interpreted as the eruption age of the tuff layer, whereas the younger whole-rock 40Ar/39Ar age is consistent with low-Temperature greenschist alteration of volcanic glass and secondary mineral growth during sedimentary burial in an extensional regime. The c. 905 Ma age for the tuff provides the first evidence for Neoproterozoic rocks offshore South-East Greenland and suggests a correlation between this sequence and the Torridon Group in the Hebridean Foreland of the Scottish Caledonides. The calc-Alkaline nature of the volcaniclastic rocks and the age of the tuff layer point toward a source area with arc-magmatism related to the Renlandian event of the Valhalla Orogeny. |
format |
Article in Journal/Newspaper |
author |
Guarnieri, Pierpaolo Storey, Michael Thomsen, Tonny B. Heredia, Benjamin Dominguez Malkki, Sebastian Næsby |
author_facet |
Guarnieri, Pierpaolo Storey, Michael Thomsen, Tonny B. Heredia, Benjamin Dominguez Malkki, Sebastian Næsby |
author_sort |
Guarnieri, Pierpaolo |
title |
First evidence for Neoproterozoic rocks offshore South-East Greenland |
title_short |
First evidence for Neoproterozoic rocks offshore South-East Greenland |
title_full |
First evidence for Neoproterozoic rocks offshore South-East Greenland |
title_fullStr |
First evidence for Neoproterozoic rocks offshore South-East Greenland |
title_full_unstemmed |
First evidence for Neoproterozoic rocks offshore South-East Greenland |
title_sort |
first evidence for neoproterozoic rocks offshore south-east greenland |
publishDate |
2022 |
url |
https://curis.ku.dk/portal/da/publications/first-evidence-for-neoproterozoic-rocks-offshore-southeast-greenland(207ca319-feea-417b-b89b-1d8172bd9ce5).html https://doi.org/10.1017/S0016756821001400 |
genre |
East Greenland Greenland North Atlantic |
genre_facet |
East Greenland Greenland North Atlantic |
op_source |
Guarnieri , P , Storey , M , Thomsen , T B , Heredia , B D & Malkki , S N 2022 , ' First evidence for Neoproterozoic rocks offshore South-East Greenland ' , Geological Magazine , vol. 159 , no. 5 , pp. 782-796 . https://doi.org/10.1017/S0016756821001400 |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.1017/S0016756821001400 |
container_title |
Geological Magazine |
container_volume |
159 |
container_issue |
5 |
container_start_page |
782 |
op_container_end_page |
796 |
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1796941490965970944 |