Tephra in deglacial ocean sediments south of Iceland: Stratigraphy, geochemistry and oceanic reservoir ages
Icelandic tephra layers within deglacial ocean sediment cores from south of Iceland have been detected and their timing with respect to the climate shifts of the last deglaciation constrained. Geochemical analysis of the tephra allowed the likely source volcanic systems to be identified. The previou...
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ftucl:oai:eprints.ucl.ac.uk.OAI2:1396382 2023-12-24T10:17:14+01:00 Tephra in deglacial ocean sediments south of Iceland: Stratigraphy, geochemistry and oceanic reservoir ages Thornalley, DJR McCave, IN Elderfield, H 2011-02 text https://discovery.ucl.ac.uk/id/eprint/1396382/1/Thornalley_Tephra%20in%20deglacial%20ocean%20sediments%20south%20of%20Iceland.pdf https://discovery.ucl.ac.uk/id/eprint/1396382/ eng eng https://discovery.ucl.ac.uk/id/eprint/1396382/1/Thornalley_Tephra%20in%20deglacial%20ocean%20sediments%20south%20of%20Iceland.pdf https://discovery.ucl.ac.uk/id/eprint/1396382/ open Journal of Quaternary Science , 26 (2) 190 - 198. (2011) tephrochronology paleoceanography North Atlantic climatology deglacial Article 2011 ftucl 2023-11-27T13:07:38Z Icelandic tephra layers within deglacial ocean sediment cores from south of Iceland have been detected and their timing with respect to the climate shifts of the last deglaciation constrained. Geochemical analysis of the tephra allowed the likely source volcanic systems to be identified. The previously known Saksunarvatn ash and Vedde ash are recognised and described. Several other major tephra layers are examined: basaltic eruption(s) of Katla at ∼8.4 ka; a basaltic eruption of Katla at ∼12.6 ka; a rhyolitic eruption of Katla at ∼13.6 ka producing tephra similar in appearance and composition to the Vedde ash; a basaltic eruption of Katla at ∼14.0 ka; and two basaltic eruptions of Grímsvötn at ∼14.6 ka and ∼15.0 ka. Abundant rhyolitic ash with a similar appearance and chemistry to the Vedde ash is found throughout the deglacial interval, predating the Vedde ash by up to 3000 years, supporting previous suggestions that there were pre-Vedde ash eruptions of rhyolite that may have contributed to North Atlantic Ash Zone 1. / This study expands the tephro-stratigraphic framework of the North Atlantic and provides a marine archive in which the timing of tephra layers (useful as isochrons) can be directly compared to major ocean and climate events of the last deglaciation. Furthermore, by correlating tephra layers and abundance changes in the polar foraminifera, Neogloboquadrina pachyderma (sinistral), to equivalent tephra events and inferred abrupt cooling/warming in Greenland ice-cores, contemporaneous 14C-dated planktonic foraminifera have been used to estimate changes in the surface radiocarbon reservoir age south of Iceland. Consistent with previous studies, larger surface reservoir ages are calculated during late Heinrich Stadial 1 and the Younger Dryas (∼2000 years and ∼800–1900 years respectively). Article in Journal/Newspaper Greenland Greenland ice cores Iceland Katla Neogloboquadrina pachyderma North Atlantic Planktonic foraminifera University College London: UCL Discovery Greenland Katla ENVELOPE(-19.062,-19.062,63.631,63.631) Saksunarvatn ENVELOPE(-7.150,-7.150,62.233,62.233) |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
topic |
tephrochronology paleoceanography North Atlantic climatology deglacial |
spellingShingle |
tephrochronology paleoceanography North Atlantic climatology deglacial Thornalley, DJR McCave, IN Elderfield, H Tephra in deglacial ocean sediments south of Iceland: Stratigraphy, geochemistry and oceanic reservoir ages |
topic_facet |
tephrochronology paleoceanography North Atlantic climatology deglacial |
description |
Icelandic tephra layers within deglacial ocean sediment cores from south of Iceland have been detected and their timing with respect to the climate shifts of the last deglaciation constrained. Geochemical analysis of the tephra allowed the likely source volcanic systems to be identified. The previously known Saksunarvatn ash and Vedde ash are recognised and described. Several other major tephra layers are examined: basaltic eruption(s) of Katla at ∼8.4 ka; a basaltic eruption of Katla at ∼12.6 ka; a rhyolitic eruption of Katla at ∼13.6 ka producing tephra similar in appearance and composition to the Vedde ash; a basaltic eruption of Katla at ∼14.0 ka; and two basaltic eruptions of Grímsvötn at ∼14.6 ka and ∼15.0 ka. Abundant rhyolitic ash with a similar appearance and chemistry to the Vedde ash is found throughout the deglacial interval, predating the Vedde ash by up to 3000 years, supporting previous suggestions that there were pre-Vedde ash eruptions of rhyolite that may have contributed to North Atlantic Ash Zone 1. / This study expands the tephro-stratigraphic framework of the North Atlantic and provides a marine archive in which the timing of tephra layers (useful as isochrons) can be directly compared to major ocean and climate events of the last deglaciation. Furthermore, by correlating tephra layers and abundance changes in the polar foraminifera, Neogloboquadrina pachyderma (sinistral), to equivalent tephra events and inferred abrupt cooling/warming in Greenland ice-cores, contemporaneous 14C-dated planktonic foraminifera have been used to estimate changes in the surface radiocarbon reservoir age south of Iceland. Consistent with previous studies, larger surface reservoir ages are calculated during late Heinrich Stadial 1 and the Younger Dryas (∼2000 years and ∼800–1900 years respectively). |
format |
Article in Journal/Newspaper |
author |
Thornalley, DJR McCave, IN Elderfield, H |
author_facet |
Thornalley, DJR McCave, IN Elderfield, H |
author_sort |
Thornalley, DJR |
title |
Tephra in deglacial ocean sediments south of Iceland: Stratigraphy, geochemistry and oceanic reservoir ages |
title_short |
Tephra in deglacial ocean sediments south of Iceland: Stratigraphy, geochemistry and oceanic reservoir ages |
title_full |
Tephra in deglacial ocean sediments south of Iceland: Stratigraphy, geochemistry and oceanic reservoir ages |
title_fullStr |
Tephra in deglacial ocean sediments south of Iceland: Stratigraphy, geochemistry and oceanic reservoir ages |
title_full_unstemmed |
Tephra in deglacial ocean sediments south of Iceland: Stratigraphy, geochemistry and oceanic reservoir ages |
title_sort |
tephra in deglacial ocean sediments south of iceland: stratigraphy, geochemistry and oceanic reservoir ages |
publishDate |
2011 |
url |
https://discovery.ucl.ac.uk/id/eprint/1396382/1/Thornalley_Tephra%20in%20deglacial%20ocean%20sediments%20south%20of%20Iceland.pdf https://discovery.ucl.ac.uk/id/eprint/1396382/ |
long_lat |
ENVELOPE(-19.062,-19.062,63.631,63.631) ENVELOPE(-7.150,-7.150,62.233,62.233) |
geographic |
Greenland Katla Saksunarvatn |
geographic_facet |
Greenland Katla Saksunarvatn |
genre |
Greenland Greenland ice cores Iceland Katla Neogloboquadrina pachyderma North Atlantic Planktonic foraminifera |
genre_facet |
Greenland Greenland ice cores Iceland Katla Neogloboquadrina pachyderma North Atlantic Planktonic foraminifera |
op_source |
Journal of Quaternary Science , 26 (2) 190 - 198. (2011) |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/1396382/1/Thornalley_Tephra%20in%20deglacial%20ocean%20sediments%20south%20of%20Iceland.pdf https://discovery.ucl.ac.uk/id/eprint/1396382/ |
op_rights |
open |
_version_ |
1786205224480800768 |