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 (2020). Smoking guns and volcanic ash: the importance of sparse tephras in Greenland ice cores. Polar research, 39 Norwegian Polar Institute 10.33265/polar.v39.3511

Preview	Text Plunkett_2020_PolarResearch.pdf - Published Version Available under License Creative Commons: Attribution-Noncommercial (CC-BY-NC). Download (2MB) | Preview
Preview	Text Plunkett_2020_PolarResearch_accepted.pdf - Accepted Version Available under License Publisher holds Copyright. Download (1MB) | Preview

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.

Interest & Impact

Downloads

369 since deposited on 07 Jul 2020
87 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item