Constraints on the Timing and Lower Crustal Accretion at the Schulz Massif, Mohns Ridge, Arctic Mid Ocean Ridges
Abstract The ultraslow‐spreading Mohns Ridge is a key supersegment of the Arctic Mid‐Ocean system, where it represents a boundary between the Jan Mayen hotspot in the south and the highly anomalous Knipovich Ridge to the north. Understanding the timing and mode of Plio‐Pleistocene seafloor spreading...
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ftdoajarticles:oai:doaj.org/article:99d20c690c2249ac89b69e6dd829b894 2024-09-15T18:10:00+00:00 Constraints on the Timing and Lower Crustal Accretion at the Schulz Massif, Mohns Ridge, Arctic Mid Ocean Ridges A. Bjerga H. H. Stubseid L. E. R. Pedersen F. Corfu M. Whitehouse R. B. Pedersen 2024-04-01T00:00:00Z https://doi.org/10.1029/2023GC010953 https://doaj.org/article/99d20c690c2249ac89b69e6dd829b894 EN eng Wiley https://doi.org/10.1029/2023GC010953 https://doaj.org/toc/1525-2027 1525-2027 doi:10.1029/2023GC010953 https://doaj.org/article/99d20c690c2249ac89b69e6dd829b894 Geochemistry, Geophysics, Geosystems, Vol 25, Iss 4, Pp n/a-n/a (2024) zircon gabbro mid‐ocean ridge tectonic window symmetric seafloor spreading ultraslow spreading ridge Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 article 2024 ftdoajarticles https://doi.org/10.1029/2023GC010953 2024-09-02T15:34:39Z Abstract The ultraslow‐spreading Mohns Ridge is a key supersegment of the Arctic Mid‐Ocean system, where it represents a boundary between the Jan Mayen hotspot in the south and the highly anomalous Knipovich Ridge to the north. Understanding the timing and mode of Plio‐Pleistocene seafloor spreading along this ridge segment is critical for establishing the recent geodynamic evolution of the Norwegian‐Greenland Sea. To investigate magmatic accretion at this ultraslow spreading ridge, we collected samples from the Schulz Massif, which is located off‐axis at 73.4°N and exposes gabbroic intrusives and mantle peridotite. The petrology and petrography of these samples indicate that the exposed crustal section underwent multiple episodes of magmatism, which are characterized by distinct crystal sizes and geochemistry. To calibrate the age of the seafloor, we combined high‐resolution and high‐precision single zircon U‐Pb geochronology. Our data suggest that seafloor spreading has been nearly symmetrical for the last ∼4.6 Myr with a time‐averaged half‐spreading rate of ∼7.4 mm yr−1. Crystal size analysis of olivine in porphyric intrusions suggests that the crustal section was fed crystal‐laden melts with recurrence rates predicted to stabilize fault‐dominated seafloor spreading. Our combined geochronological and crystal size approach gives a critical perspective on the mode of seafloor spreading in the Mohns Ridge and allows insights into accretionary mechanisms and crustal structures during symmetric seafloor spreading. Article in Journal/Newspaper Greenland Greenland Sea Jan Mayen Directory of Open Access Journals: DOAJ Articles Geochemistry, Geophysics, Geosystems 25 4 |
institution |
Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
zircon gabbro mid‐ocean ridge tectonic window symmetric seafloor spreading ultraslow spreading ridge Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
spellingShingle |
zircon gabbro mid‐ocean ridge tectonic window symmetric seafloor spreading ultraslow spreading ridge Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 A. Bjerga H. H. Stubseid L. E. R. Pedersen F. Corfu M. Whitehouse R. B. Pedersen Constraints on the Timing and Lower Crustal Accretion at the Schulz Massif, Mohns Ridge, Arctic Mid Ocean Ridges |
topic_facet |
zircon gabbro mid‐ocean ridge tectonic window symmetric seafloor spreading ultraslow spreading ridge Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
description |
Abstract The ultraslow‐spreading Mohns Ridge is a key supersegment of the Arctic Mid‐Ocean system, where it represents a boundary between the Jan Mayen hotspot in the south and the highly anomalous Knipovich Ridge to the north. Understanding the timing and mode of Plio‐Pleistocene seafloor spreading along this ridge segment is critical for establishing the recent geodynamic evolution of the Norwegian‐Greenland Sea. To investigate magmatic accretion at this ultraslow spreading ridge, we collected samples from the Schulz Massif, which is located off‐axis at 73.4°N and exposes gabbroic intrusives and mantle peridotite. The petrology and petrography of these samples indicate that the exposed crustal section underwent multiple episodes of magmatism, which are characterized by distinct crystal sizes and geochemistry. To calibrate the age of the seafloor, we combined high‐resolution and high‐precision single zircon U‐Pb geochronology. Our data suggest that seafloor spreading has been nearly symmetrical for the last ∼4.6 Myr with a time‐averaged half‐spreading rate of ∼7.4 mm yr−1. Crystal size analysis of olivine in porphyric intrusions suggests that the crustal section was fed crystal‐laden melts with recurrence rates predicted to stabilize fault‐dominated seafloor spreading. Our combined geochronological and crystal size approach gives a critical perspective on the mode of seafloor spreading in the Mohns Ridge and allows insights into accretionary mechanisms and crustal structures during symmetric seafloor spreading. |
format |
Article in Journal/Newspaper |
author |
A. Bjerga H. H. Stubseid L. E. R. Pedersen F. Corfu M. Whitehouse R. B. Pedersen |
author_facet |
A. Bjerga H. H. Stubseid L. E. R. Pedersen F. Corfu M. Whitehouse R. B. Pedersen |
author_sort |
A. Bjerga |
title |
Constraints on the Timing and Lower Crustal Accretion at the Schulz Massif, Mohns Ridge, Arctic Mid Ocean Ridges |
title_short |
Constraints on the Timing and Lower Crustal Accretion at the Schulz Massif, Mohns Ridge, Arctic Mid Ocean Ridges |
title_full |
Constraints on the Timing and Lower Crustal Accretion at the Schulz Massif, Mohns Ridge, Arctic Mid Ocean Ridges |
title_fullStr |
Constraints on the Timing and Lower Crustal Accretion at the Schulz Massif, Mohns Ridge, Arctic Mid Ocean Ridges |
title_full_unstemmed |
Constraints on the Timing and Lower Crustal Accretion at the Schulz Massif, Mohns Ridge, Arctic Mid Ocean Ridges |
title_sort |
constraints on the timing and lower crustal accretion at the schulz massif, mohns ridge, arctic mid ocean ridges |
publisher |
Wiley |
publishDate |
2024 |
url |
https://doi.org/10.1029/2023GC010953 https://doaj.org/article/99d20c690c2249ac89b69e6dd829b894 |
genre |
Greenland Greenland Sea Jan Mayen |
genre_facet |
Greenland Greenland Sea Jan Mayen |
op_source |
Geochemistry, Geophysics, Geosystems, Vol 25, Iss 4, Pp n/a-n/a (2024) |
op_relation |
https://doi.org/10.1029/2023GC010953 https://doaj.org/toc/1525-2027 1525-2027 doi:10.1029/2023GC010953 https://doaj.org/article/99d20c690c2249ac89b69e6dd829b894 |
op_doi |
https://doi.org/10.1029/2023GC010953 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
25 |
container_issue |
4 |
_version_ |
1810447602589630464 |