Smoking guns and volcanic ash: The importance of sparse tephras in Greenland ice cores
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Smoking guns and volcanic ash : The importance of sparse tephras in Greenland ice cores. / Plunkett, Gill; Sigl, Michael; Pilcher, Jonathan R.; McConnell, Joseph R.; Chellman, Nathan; Steffensen, J. P.; Büntgen, Ulf.
I: Polar Research, Bind 39, 3511, 2020.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Smoking guns and volcanic ash
T2 - The importance of sparse tephras in Greenland ice cores
AU - Plunkett, Gill
AU - Sigl, Michael
AU - Pilcher, Jonathan R.
AU - McConnell, Joseph R.
AU - Chellman, Nathan
AU - Steffensen, J. P.
AU - Büntgen, Ulf
PY - 2020
Y1 - 2020
N2 - Volcanic ash (fine-grained tephra) within Greenland ice cores can complement the understanding of past volcanism and its environmental and societal impacts. The presence of ash in sparse concentrations in the ice raises questions about whether such material represents primary ashfall in Greenland or resuspended (remobilized) material from continental areas. In this article, we investigate this issue by examining tephra content in quasi-annual samples from two Greenland ice cores during a period of ca. 20 years and considering their relationships with sulphur and particulate data from the same cores. We focus on the interval 815–835 CE as it encompasses a phase (818–822 CE) of heightened volcanogenic sulphur previously ascribed to an eruption of Katla, Iceland. We find that tephra is a frequent but not continuous feature within the ice, unlike similarly sized particulate matter. A solitary ash shard whose major element geochemistry is consistent with Katla corroborates the attribution of the 822±1 CE sulphur peak to this source, clearly showing that a single shard can signify primary ashfall. Other tephras are present in similarly low abundances, but their geochemistries are less certainly attributable to specific sources. Although these tephra shards tend to coincide with elevated sulphur and fine (<10 μm) particulates, they are not associated with increased coarse (>10 μm) particle concentrations that might be expected if the shards had been transported by dust storms. We conclude that the sparse shards derive from primary ashfall, and we argue that low tephra concentrations should not be dismissed as insignificant.
AB - Volcanic ash (fine-grained tephra) within Greenland ice cores can complement the understanding of past volcanism and its environmental and societal impacts. The presence of ash in sparse concentrations in the ice raises questions about whether such material represents primary ashfall in Greenland or resuspended (remobilized) material from continental areas. In this article, we investigate this issue by examining tephra content in quasi-annual samples from two Greenland ice cores during a period of ca. 20 years and considering their relationships with sulphur and particulate data from the same cores. We focus on the interval 815–835 CE as it encompasses a phase (818–822 CE) of heightened volcanogenic sulphur previously ascribed to an eruption of Katla, Iceland. We find that tephra is a frequent but not continuous feature within the ice, unlike similarly sized particulate matter. A solitary ash shard whose major element geochemistry is consistent with Katla corroborates the attribution of the 822±1 CE sulphur peak to this source, clearly showing that a single shard can signify primary ashfall. Other tephras are present in similarly low abundances, but their geochemistries are less certainly attributable to specific sources. Although these tephra shards tend to coincide with elevated sulphur and fine (<10 μm) particulates, they are not associated with increased coarse (>10 μm) particle concentrations that might be expected if the shards had been transported by dust storms. We conclude that the sparse shards derive from primary ashfall, and we argue that low tephra concentrations should not be dismissed as insignificant.
KW - Dust storms
KW - Katla
KW - Primary ashfall
KW - Resuspended volcanic ash
KW - Tephrochronology
KW - Volcanic eruptions
UR - http://www.scopus.com/inward/record.url?scp=85088263274&partnerID=8YFLogxK
U2 - 10.33265/polar.v39.3511
DO - 10.33265/polar.v39.3511
M3 - Journal article
AN - SCOPUS:85088263274
VL - 39
JO - Polar Research
JF - Polar Research
SN - 0800-0395
M1 - 3511
ER -
ID: 247950850