Evaluating tephrochronology in the permafrost peatlands of Northern Sweden
Cooper, CL; Swindles, GT; Watson, ET; et al.Savov, IP; Galka, M; Gallego-Sala, AV; Borken, W
Date: 22 November 2018
Journal
Quaternary Geochronology
Publisher
Elsevier
Publisher DOI
Abstract
Tephrochronology is an increasingly important tool for the dating of sediment and
peat profiles for palaeoecological, palaeoclimatic and archaeological research.
However, although much work has been done on tephra in temperate peatlands,
there have been very few in-depth investigations of permafrost peatlands. Here we
present ...
Tephrochronology is an increasingly important tool for the dating of sediment and
peat profiles for palaeoecological, palaeoclimatic and archaeological research.
However, although much work has been done on tephra in temperate peatlands,
there have been very few in-depth investigations of permafrost peatlands. Here we
present the analysis of nine peatland cores from Abisko, northern Sweden, and show
that the presence of tephra layers may be highly variable even over a scale of <10
km. Using electron probe microanalysis (EPMA) combined with age-depth profiles
compiled from radiocarbon (14C) and 210Pb dating of peat records, we identify the
Hekla 1104, Hekla 1158, Hekla-Selsund and the Hekla 4 tephra layers. We also infer
the presence of the Askja 1875 tephra, in addition to an unassigned tephra dating
from between 1971-1987 AD in two separate cores. Five of the nine analysed cores
do not contain distinct tephra layers. Volcanic ash deposits in northern Scandinavia
are subject to both regional-scale variations in climate and atmospheric circulation,
and local-scale variations on the order of tens of kilometres in topography,
vegetation, snow cover, and ground permeability. The extreme inconsistency of
tephra preservation within a small study area (~3000 km2) brings into question the
reliability of tephrochronology within permafrost peatlands, and highlights the
necessity of alternative methods for dating peat profiles in this region.
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