A1 Refereed original research article in a scientific journal

A new, ~4500‐year varve record and high‐resolution tephrochronology from lake Hämälänlampi, eastern Finland, provides age constraints for the Furnas C and the Glen Garry/Askja A‐2000 eruptions;




AuthorsKalliokoski, Maarit; Erola, Veera; Saarni, Saija

PublisherWiley

Publication year2026

Journal: Journal of Quaternary Science

ISSN0267-8179

eISSN1099-1417

DOIhttps://doi.org/10.1002/jqs.70079

Publication's open availability at the time of reportingOpen Access

Publication channel's open availability Partially Open Access publication channel

Web address https://doi.org/10.1002/jqs.70079

Self-archived copy’s web addresshttps://research.utu.fi/converis/portal/detail/Publication/524882665

Self-archived copy's licenceCC BY

Self-archived copy's versionPublisher`s PDF


Abstract

The northern European distal cryptotephra framework is constantly developing both in terms of identification of new tephra horizons and improved age constraints for the already well-established tephra marker horizons. However, many prehistoric tephra layers have only been dated by the radiocarbon method, with its inherent problems. Here, we present a new similar to 4500-year, continuously varved lacustrine sediment record and tephrochronology from lake Hamalanlampi, eastern Finland. The varve chronology was established by repeated varve counts from epoxy-impregnated sediment blocks and selected elemental maps (Si, K, Fe and Mn) produced by micro-XRF scanning. The sediment core was investigated for the presence of cryptotephra, and the exact location of the nine identified cryptotephra horizons was pinpointed with either 0.5- or 1-cm depth resolution. The volcanic glass shards were geochemically characterised and correlated to their source eruptions. As a result, we report the first findings of the Hekla 1947, Furnas C and Hekla C tephras in Finnish environmental records, and provide varve ages for the Furnas C, Hekla Y, Hekla C and Oraefajokull 3.5 ka tephras for the first time. We also suggest a new, high-resolution varve age 128-117 BCE for the Glen Garry tephra, based on integration of varve ages from several studies. (c) 2026 The Author(s). Journal of Quaternary Science Published by John Wiley & Sons Ltd.



Keywords:
Finnish tephrochronologyFurnas C tephraHekla tephraOraefajokull 3.5 ka tephravarve chronology

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Funding information in the publication
We thank Timo Saarinen for his help in the early stages of this research project and Tapio Suominen for assistance in lake coring. We acknowledge financial support from the Academy of Finland (grant no. 339789) and Maa- ja vesitekniikan tuki ry. Open-access publishing was facilitated by Turun yliopisto, as part of the Wiley-FinELib agreement. Open access publishing facilitated by Turun yliopisto, as part of the Wiley - FinELib agreement.


Last updated on 08/06/2026 12:02:30 PM