Age, formation and significance of loess deposits in central Sweden
Loess deposits are common in the mid-latitudes and are excellent records of past climate, landscape change and dust. However, loess deposits are seldom reported from Fennoscandia. Here we investigate two former glaciofluvial areas in central Sweden, Brattforsheden and Bonasheden, where post-glacial...
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ftunicagliariris:oai:iris.unica.it:11584/344073 2024-04-21T08:01:52+00:00 Age, formation and significance of loess deposits in central Sweden Stevens, T Sechi, D Tziavaras, C Schneider, R Banak, A Andreucci, S Hattestrand, M Pascucci, V Stevens, T Sechi, D Tziavaras, C Schneider, R Banak, A Andreucci, S Hattestrand, M Pascucci, V 2022 https://hdl.handle.net/11584/344073 https://doi.org/10.1002/esp.5456 https://onlinelibrary.wiley.com/doi/10.1002/esp.5456 eng eng info:eu-repo/semantics/altIdentifier/wos/WOS:000842829200001 volume:47 issue:14 firstpage:3276 lastpage:3301 numberofpages:26 journal:EARTH SURFACE PROCESSES AND LANDFORMS https://hdl.handle.net/11584/344073 doi:10.1002/esp.5456 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85136527300 https://onlinelibrary.wiley.com/doi/10.1002/esp.5456 Aeolian Holocene Luminescence OSL Quaternary SEM info:eu-repo/semantics/article 2022 ftunicagliariris https://doi.org/10.1002/esp.5456 2024-03-25T15:55:04Z Loess deposits are common in the mid-latitudes and are excellent records of past climate, landscape change and dust. However, loess deposits are seldom reported from Fennoscandia. Here we investigate two former glaciofluvial areas in central Sweden, Brattforsheden and Bonasheden, where post-glacial loess and sand dune activity have been documented previously. Based on detailed mapping, grain size, scanning electron microscopy and optically stimulated luminescence dating analyses, we confirm the presence of loess deposits at the sites and extend the known area of loess coverage. Our results suggest that loess deposits are more common than previously thought in Sweden. The results also demonstrate that basal parts of the loess are often mixed with underlying sediment, which may be a common feature of thin loess deposits close to former ice margins. Quartz luminescence is well suited for dating these deposits, but ages from the mixed basal loess layers are older than expected, while ages from undisturbed loess extend to c. 5 ka. The loess ages contrast with the timing of main dune activity in these areas, which is dominantly in the 1-3 kyr post-deglaciation (c. 10.9-10.5 cal kyr BP). We suggest that either sediment mixing during soil formation is responsible for the mid-Holocene loess ages, or that the loess deposits record periodic landscape destabilization into the mid-Holocene. Furthermore, there is a clear topographic control on aeolian sedimentary facies, with loess mantling high ground and dunes restricted to valleys. Loess deposits are also primarily found to the south and southwest of source areas, implying transport from the north and east. This pattern contrasts with evidence for NW winds inferred from associated sand dunes. At present, the reasons for this mismatch are unclear, although one possible explanation is that silts deposited at higher elevations were affected by Ekman flow deflection of NW surface winds. Article in Journal/Newspaper Fennoscandia Università degli Studi di Cagliari: UNICA IRIS Earth Surface Processes and Landforms 47 14 3276 3301 |
institution |
Open Polar |
collection |
Università degli Studi di Cagliari: UNICA IRIS |
op_collection_id |
ftunicagliariris |
language |
English |
topic |
Aeolian Holocene Luminescence OSL Quaternary SEM |
spellingShingle |
Aeolian Holocene Luminescence OSL Quaternary SEM Stevens, T Sechi, D Tziavaras, C Schneider, R Banak, A Andreucci, S Hattestrand, M Pascucci, V Age, formation and significance of loess deposits in central Sweden |
topic_facet |
Aeolian Holocene Luminescence OSL Quaternary SEM |
description |
Loess deposits are common in the mid-latitudes and are excellent records of past climate, landscape change and dust. However, loess deposits are seldom reported from Fennoscandia. Here we investigate two former glaciofluvial areas in central Sweden, Brattforsheden and Bonasheden, where post-glacial loess and sand dune activity have been documented previously. Based on detailed mapping, grain size, scanning electron microscopy and optically stimulated luminescence dating analyses, we confirm the presence of loess deposits at the sites and extend the known area of loess coverage. Our results suggest that loess deposits are more common than previously thought in Sweden. The results also demonstrate that basal parts of the loess are often mixed with underlying sediment, which may be a common feature of thin loess deposits close to former ice margins. Quartz luminescence is well suited for dating these deposits, but ages from the mixed basal loess layers are older than expected, while ages from undisturbed loess extend to c. 5 ka. The loess ages contrast with the timing of main dune activity in these areas, which is dominantly in the 1-3 kyr post-deglaciation (c. 10.9-10.5 cal kyr BP). We suggest that either sediment mixing during soil formation is responsible for the mid-Holocene loess ages, or that the loess deposits record periodic landscape destabilization into the mid-Holocene. Furthermore, there is a clear topographic control on aeolian sedimentary facies, with loess mantling high ground and dunes restricted to valleys. Loess deposits are also primarily found to the south and southwest of source areas, implying transport from the north and east. This pattern contrasts with evidence for NW winds inferred from associated sand dunes. At present, the reasons for this mismatch are unclear, although one possible explanation is that silts deposited at higher elevations were affected by Ekman flow deflection of NW surface winds. |
author2 |
Stevens, T Sechi, D Tziavaras, C Schneider, R Banak, A Andreucci, S Hattestrand, M Pascucci, V |
format |
Article in Journal/Newspaper |
author |
Stevens, T Sechi, D Tziavaras, C Schneider, R Banak, A Andreucci, S Hattestrand, M Pascucci, V |
author_facet |
Stevens, T Sechi, D Tziavaras, C Schneider, R Banak, A Andreucci, S Hattestrand, M Pascucci, V |
author_sort |
Stevens, T |
title |
Age, formation and significance of loess deposits in central Sweden |
title_short |
Age, formation and significance of loess deposits in central Sweden |
title_full |
Age, formation and significance of loess deposits in central Sweden |
title_fullStr |
Age, formation and significance of loess deposits in central Sweden |
title_full_unstemmed |
Age, formation and significance of loess deposits in central Sweden |
title_sort |
age, formation and significance of loess deposits in central sweden |
publishDate |
2022 |
url |
https://hdl.handle.net/11584/344073 https://doi.org/10.1002/esp.5456 https://onlinelibrary.wiley.com/doi/10.1002/esp.5456 |
genre |
Fennoscandia |
genre_facet |
Fennoscandia |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:000842829200001 volume:47 issue:14 firstpage:3276 lastpage:3301 numberofpages:26 journal:EARTH SURFACE PROCESSES AND LANDFORMS https://hdl.handle.net/11584/344073 doi:10.1002/esp.5456 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85136527300 https://onlinelibrary.wiley.com/doi/10.1002/esp.5456 |
op_doi |
https://doi.org/10.1002/esp.5456 |
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Earth Surface Processes and Landforms |
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47 |
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14 |
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