A1 Refereed original research article in a scientific journal
Unlocking varve details: high-resolution sampling via freeze-melt technique
Authors: Ojala, Antti E. K.; Lapointe, Francois; Kosonen, Emilia
Publisher: Springer Science and Business Media LLC
Publication year: 2025
Journal:: Journal of Paleolimnology
ISSN: 0921-2728
eISSN: 1573-0417
DOI: https://doi.org/10.1007/s10933-025-00375-x
Web address : https://doi.org/10.1007/s10933-025-00375-x
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/504920060
Sediment archives, and especially annually laminated sediments, can provide valuable records of past climate and environmental change. However, the extraction of high-resolution sub-millimetre (seasonal to annual) and uncontaminated discrete subsamples from fresh sediment cores has proven difficult, time-consuming and labour-intensive. Obtaining such samples is essential for determining the relationship between measurable sediment proxies and specific climate variables, as well as for the quantification of paleoproxies. In this technical note we present a freeze-melt technique for a high-resolution subsampling of sediment sequences. This method is based on freezing and melting of fresh sediments to obtain very thin discrete subsamples. We provide details of the method and application examples using two case studies (10Be, 137Cs) with clastic-biogenic varves from lakes Nautaj & auml;rvi and Ristij & auml;rvi in Finland. We discuss the potential advantages of the method, as well as risks and limitations that need to be considered.
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Funding information in the publication:
FL gratefully acknowledges support from the U.S. National Science Foundation through the EAGER program
(NSF Award #2404514) as well as a grant from the P4Climate program (Award #2402628) awarded to FL.
This research was conducted with collaboration of Digital Waters Flagship (DIWA) (decision no. 359247) funded by the Research Council of Finland. Open Access funding provided by Geological Survey of Finland.
