The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea
The caldera-forming eruption of the Aniakchak volcano in the Aleutian Range on the Alaskan Peninsula at 3.6 cal kyr BP was one of the largest Holocene eruptions worldwide. The resulting ash is found as a visible sediment layer in several Alaskan sites and as a cryptotephra on Newfoundland and Greenl...
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ftdoajarticles:oai:doaj.org/article:94cbfcfad3aa4b5da0605472311dbfae 2023-05-15T15:03:35+02:00 The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea C. Pearce A. Varhelyi S. Wastegård F. Muschitiello N. Barrientos M. O'Regan T. M. Cronin L. Gemery I. Semiletov J. Backman M. Jakobsson 2017-04-01T00:00:00Z https://doi.org/10.5194/cp-13-303-2017 https://doaj.org/article/94cbfcfad3aa4b5da0605472311dbfae EN eng Copernicus Publications http://www.clim-past.net/13/303/2017/cp-13-303-2017.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 doi:10.5194/cp-13-303-2017 https://doaj.org/article/94cbfcfad3aa4b5da0605472311dbfae Climate of the Past, Vol 13, Iss 4, Pp 303-316 (2017) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2017 ftdoajarticles https://doi.org/10.5194/cp-13-303-2017 2022-12-31T05:32:59Z The caldera-forming eruption of the Aniakchak volcano in the Aleutian Range on the Alaskan Peninsula at 3.6 cal kyr BP was one of the largest Holocene eruptions worldwide. The resulting ash is found as a visible sediment layer in several Alaskan sites and as a cryptotephra on Newfoundland and Greenland. This large geographic distribution, combined with the fact that the eruption is relatively well constrained in time using radiocarbon dating of lake sediments and annual layer counts in ice cores, makes it an excellent stratigraphic marker for dating and correlating mid–late Holocene sediment and paleoclimate records. This study presents the outcome of a targeted search for the Aniakchak tephra in a marine sediment core from the Arctic Ocean, namely Core SWERUS-L2-2-PC1 (2PC), raised from 57 m water depth in Herald Canyon, western Chukchi Sea. High concentrations of tephra shards, with a geochemical signature matching that of Aniakchak ash, were observed across a more than 1.5 m long sediment sequence. Since the primary input of volcanic ash is through atmospheric transport, and assuming that bioturbation can account for mixing up to ca. 10 cm of the marine sediment deposited at the coring site, the broad signal is interpreted as sustained reworking at the sediment source input. The isochron is therefore placed at the base of the sudden increase in tephra concentrations rather than at the maximum concentration. This interpretation of major reworking is strengthened by analysis of grain size distribution which points to ice rafting as an important secondary transport mechanism of volcanic ash. Combined with radiocarbon dates on mollusks in the same sediment core, the volcanic marker is used to calculate a marine radiocarbon reservoir age offset Δ R = 477 ± 60 years. This relatively high value may be explained by the major influence of typically <q>carbon-old</q> Pacific waters, and it agrees well with recent estimates of Δ R along the northwest Alaskan coast, possibly indicating stable oceanographic ... Article in Journal/Newspaper Arctic Arctic Ocean Chukchi Chukchi Sea Greenland Newfoundland Directory of Open Access Journals: DOAJ Articles Arctic Arctic Ocean Chukchi Sea Greenland Pacific Climate of the Past 13 4 303 316 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 C. Pearce A. Varhelyi S. Wastegård F. Muschitiello N. Barrientos M. O'Regan T. M. Cronin L. Gemery I. Semiletov J. Backman M. Jakobsson The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
The caldera-forming eruption of the Aniakchak volcano in the Aleutian Range on the Alaskan Peninsula at 3.6 cal kyr BP was one of the largest Holocene eruptions worldwide. The resulting ash is found as a visible sediment layer in several Alaskan sites and as a cryptotephra on Newfoundland and Greenland. This large geographic distribution, combined with the fact that the eruption is relatively well constrained in time using radiocarbon dating of lake sediments and annual layer counts in ice cores, makes it an excellent stratigraphic marker for dating and correlating mid–late Holocene sediment and paleoclimate records. This study presents the outcome of a targeted search for the Aniakchak tephra in a marine sediment core from the Arctic Ocean, namely Core SWERUS-L2-2-PC1 (2PC), raised from 57 m water depth in Herald Canyon, western Chukchi Sea. High concentrations of tephra shards, with a geochemical signature matching that of Aniakchak ash, were observed across a more than 1.5 m long sediment sequence. Since the primary input of volcanic ash is through atmospheric transport, and assuming that bioturbation can account for mixing up to ca. 10 cm of the marine sediment deposited at the coring site, the broad signal is interpreted as sustained reworking at the sediment source input. The isochron is therefore placed at the base of the sudden increase in tephra concentrations rather than at the maximum concentration. This interpretation of major reworking is strengthened by analysis of grain size distribution which points to ice rafting as an important secondary transport mechanism of volcanic ash. Combined with radiocarbon dates on mollusks in the same sediment core, the volcanic marker is used to calculate a marine radiocarbon reservoir age offset Δ R = 477 ± 60 years. This relatively high value may be explained by the major influence of typically <q>carbon-old</q> Pacific waters, and it agrees well with recent estimates of Δ R along the northwest Alaskan coast, possibly indicating stable oceanographic ... |
format |
Article in Journal/Newspaper |
author |
C. Pearce A. Varhelyi S. Wastegård F. Muschitiello N. Barrientos M. O'Regan T. M. Cronin L. Gemery I. Semiletov J. Backman M. Jakobsson |
author_facet |
C. Pearce A. Varhelyi S. Wastegård F. Muschitiello N. Barrientos M. O'Regan T. M. Cronin L. Gemery I. Semiletov J. Backman M. Jakobsson |
author_sort |
C. Pearce |
title |
The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea |
title_short |
The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea |
title_full |
The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea |
title_fullStr |
The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea |
title_full_unstemmed |
The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea |
title_sort |
3.6 ka aniakchak tephra in the arctic ocean: a constraint on the holocene radiocarbon reservoir age in the chukchi sea |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/cp-13-303-2017 https://doaj.org/article/94cbfcfad3aa4b5da0605472311dbfae |
geographic |
Arctic Arctic Ocean Chukchi Sea Greenland Pacific |
geographic_facet |
Arctic Arctic Ocean Chukchi Sea Greenland Pacific |
genre |
Arctic Arctic Ocean Chukchi Chukchi Sea Greenland Newfoundland |
genre_facet |
Arctic Arctic Ocean Chukchi Chukchi Sea Greenland Newfoundland |
op_source |
Climate of the Past, Vol 13, Iss 4, Pp 303-316 (2017) |
op_relation |
http://www.clim-past.net/13/303/2017/cp-13-303-2017.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 doi:10.5194/cp-13-303-2017 https://doaj.org/article/94cbfcfad3aa4b5da0605472311dbfae |
op_doi |
https://doi.org/10.5194/cp-13-303-2017 |
container_title |
Climate of the Past |
container_volume |
13 |
container_issue |
4 |
container_start_page |
303 |
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316 |
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