First evidence for Neoproterozoic rocks offshore South-East Greenland
Abstract 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 even...
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crcambridgeupr:10.1017/s0016756821001400 2024-03-03T08:43:59+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 http://dx.doi.org/10.1017/s0016756821001400 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756821001400 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Geological Magazine volume 159, issue 5, page 782-796 ISSN 0016-7568 1469-5081 Geology journal-article 2022 crcambridgeupr https://doi.org/10.1017/s0016756821001400 2024-02-08T08:39:53Z Abstract 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 40 Ar/ 39 Ar 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 40 Ar/ 39 Ar 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 40 Ar/ 39 Ar 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 Cambridge University Press Greenland Rockall Plateau ENVELOPE(-18.833,-18.833,56.333,56.333) Valhalla ENVELOPE(161.933,161.933,-77.583,-77.583) Geological Magazine 1 15 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Geology |
spellingShingle |
Geology Guarnieri, Pierpaolo Storey, Michael Thomsen, Tonny B. Heredia, Benjamin Dominguez Malkki, Sebastian Næsby First evidence for Neoproterozoic rocks offshore South-East Greenland |
topic_facet |
Geology |
description |
Abstract 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 40 Ar/ 39 Ar 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 40 Ar/ 39 Ar 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 40 Ar/ 39 Ar 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 |
publisher |
Cambridge University Press (CUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1017/s0016756821001400 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756821001400 |
long_lat |
ENVELOPE(-18.833,-18.833,56.333,56.333) ENVELOPE(161.933,161.933,-77.583,-77.583) |
geographic |
Greenland Rockall Plateau Valhalla |
geographic_facet |
Greenland Rockall Plateau Valhalla |
genre |
East Greenland Greenland North Atlantic |
genre_facet |
East Greenland Greenland North Atlantic |
op_source |
Geological Magazine volume 159, issue 5, page 782-796 ISSN 0016-7568 1469-5081 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0016756821001400 |
container_title |
Geological Magazine |
container_start_page |
1 |
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15 |
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1792499464876851200 |