Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland
A 25-m-long sediment record spanning the time from the Eemian to the Holocene was recovered from Sokli, northeast Finland. This study focuses on a 6-m-long sediment interval that is dated to the Early Weichselian period (MIS 5d and 5c) and consists of lacustrine and fluvial deposits. Using chironomi...
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ftbirkbeckcoll:oai:eprints.bbk.ac.uk.oai2:41754 2023-05-15T16:11:52+02:00 Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland Engels, Stefan Helmens, K.F. Valiranta, M. Brooks, S.J. Birks, H.J.B. 2010-10 https://eprints.bbk.ac.uk/id/eprint/41754/ https://doi.org/10.1111/j.1502-3885.2010.00163.x unknown Wiley Engels, Stefan and Helmens, K.F. and Valiranta, M. and Brooks, S.J. and Birks, H.J.B. (2010) Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland. Boreas 39 (4), pp. 689-704. ISSN 0300-9483. Department of Geography Article PeerReviewed 2010 ftbirkbeckcoll https://doi.org/10.1111/j.1502-3885.2010.00163.x 2022-01-09T09:08:25Z A 25-m-long sediment record spanning the time from the Eemian to the Holocene was recovered from Sokli, northeast Finland. This study focuses on a 6-m-long sediment interval that is dated to the Early Weichselian period (MIS 5d and 5c) and consists of lacustrine and fluvial deposits. Using chironomid remains, botanical and zoological macroremains as well as sediment lithology, we were able to reconstruct past changes in the environment, including climate. The results indicate that the site was situated on a flood-plain during the latter stages of MIS 5d (Herning Stadial) and that summer temperatures might have been ~6C lower than at present. Although this value should be treated with caution, as numerical analysis shows that it has a very poor fit-to-temperature, this low reconstructed value concurs with several other reconstructions that are available from western Europe. During MIS 5c (Brørup interstadial), the depositional environment changed into a lake system, initially with stratification of the water and subsequently with complete mixing and a strong influence of streams. Both chironomid- based and macroremain-based temperature inferences indicate past July air temperatures that were significantly higher than at present. This result is in contrast to other (low-resolution) reconstructions from northern Fennoscandia that indicate past temperatures 6–7C lower than present using fossil coleopteran assemblages. However, several central European sites indicate that there was a phase during the Brørup interstadial that was characterized by high summer temperatures, and a comparison between the high-resolution reconstructions from western Europe and the results presented in this study suggests that the north–south July air temperature gradient between the mid- and high-latitudes was much weaker during the Brørup interstadial than it is at present. High solar insolation values (particularly the obliquity) during the Brørup interstadial might explain the low summer temperature gradient over the European continent. A return to fluvial conditions occurred in the upper parts of the sediment sequence, and, after a brief interval of gyttja deposition under cooling conditions, the site became glaciated during MIS 5b. Article in Journal/Newspaper Fennoscandia BIROn - Birkbeck Institutional Research Online (Birkbeck University of London) Boreas 39 4 689 704 |
institution |
Open Polar |
collection |
BIROn - Birkbeck Institutional Research Online (Birkbeck University of London) |
op_collection_id |
ftbirkbeckcoll |
language |
unknown |
topic |
Department of Geography |
spellingShingle |
Department of Geography Engels, Stefan Helmens, K.F. Valiranta, M. Brooks, S.J. Birks, H.J.B. Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland |
topic_facet |
Department of Geography |
description |
A 25-m-long sediment record spanning the time from the Eemian to the Holocene was recovered from Sokli, northeast Finland. This study focuses on a 6-m-long sediment interval that is dated to the Early Weichselian period (MIS 5d and 5c) and consists of lacustrine and fluvial deposits. Using chironomid remains, botanical and zoological macroremains as well as sediment lithology, we were able to reconstruct past changes in the environment, including climate. The results indicate that the site was situated on a flood-plain during the latter stages of MIS 5d (Herning Stadial) and that summer temperatures might have been ~6C lower than at present. Although this value should be treated with caution, as numerical analysis shows that it has a very poor fit-to-temperature, this low reconstructed value concurs with several other reconstructions that are available from western Europe. During MIS 5c (Brørup interstadial), the depositional environment changed into a lake system, initially with stratification of the water and subsequently with complete mixing and a strong influence of streams. Both chironomid- based and macroremain-based temperature inferences indicate past July air temperatures that were significantly higher than at present. This result is in contrast to other (low-resolution) reconstructions from northern Fennoscandia that indicate past temperatures 6–7C lower than present using fossil coleopteran assemblages. However, several central European sites indicate that there was a phase during the Brørup interstadial that was characterized by high summer temperatures, and a comparison between the high-resolution reconstructions from western Europe and the results presented in this study suggests that the north–south July air temperature gradient between the mid- and high-latitudes was much weaker during the Brørup interstadial than it is at present. High solar insolation values (particularly the obliquity) during the Brørup interstadial might explain the low summer temperature gradient over the European continent. A return to fluvial conditions occurred in the upper parts of the sediment sequence, and, after a brief interval of gyttja deposition under cooling conditions, the site became glaciated during MIS 5b. |
format |
Article in Journal/Newspaper |
author |
Engels, Stefan Helmens, K.F. Valiranta, M. Brooks, S.J. Birks, H.J.B. |
author_facet |
Engels, Stefan Helmens, K.F. Valiranta, M. Brooks, S.J. Birks, H.J.B. |
author_sort |
Engels, Stefan |
title |
Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland |
title_short |
Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland |
title_full |
Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland |
title_fullStr |
Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland |
title_full_unstemmed |
Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland |
title_sort |
early weichselian (mis 5d and 5c) temperatures and environmental changes in northern fennoscandia as recorded by chironomids and macroremains at sokli, northeast finland |
publisher |
Wiley |
publishDate |
2010 |
url |
https://eprints.bbk.ac.uk/id/eprint/41754/ https://doi.org/10.1111/j.1502-3885.2010.00163.x |
genre |
Fennoscandia |
genre_facet |
Fennoscandia |
op_relation |
Engels, Stefan and Helmens, K.F. and Valiranta, M. and Brooks, S.J. and Birks, H.J.B. (2010) Early Weichselian (MIS 5d and 5c) temperatures and environmental changes in northern Fennoscandia as recorded by chironomids and macroremains at Sokli, northeast Finland. Boreas 39 (4), pp. 689-704. ISSN 0300-9483. |
op_doi |
https://doi.org/10.1111/j.1502-3885.2010.00163.x |
container_title |
Boreas |
container_volume |
39 |
container_issue |
4 |
container_start_page |
689 |
op_container_end_page |
704 |
_version_ |
1765997072646930432 |