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 Bonäsheden, where post-glacial...
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Uppsala universitet, Luft-, vatten- och landskapslära
2022
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ftuppsalauniv:oai:DiVA.org:uu-480967 2023-11-12T04:17:02+01:00 Age, formation and significance of loess deposits in central Sweden Stevens, Thomas Sechi, Daniele Tziavaras, Charilaos Schneider, Ramona Banak, Adriano Andreucci, Stefano Hätterstrand, Martina Pascucci, Vincenzo 2022 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-480967 https://doi.org/10.1002/esp.5456 eng eng Uppsala universitet, Luft-, vatten- och landskapslära Uppsala universitet, Institutionen för geovetenskaper Department of Architecture, Design and Planning University of Sassari Alghero SS Italy Croatian Geological Survey, Department for Geology Zagreb Croatia Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Cittadella Universitaria (Blocco A) Monserrato CA Italy Department of Physical Geography Stockholm University Stockholm Sweden Department of Architecture, Design and Planning University of Sassari Alghero SS Italy;Institute of Geology and Petroleum Technologies Kazan Federal University Kazzan Russia Earth Surface Processes and Landforms, 0197-9337, 2022, 47:14, s. 3276-3301 orcid:0000-0002-6662-6650 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-480967 doi:10.1002/esp.5456 ISI:000842829200001 info:eu-repo/semantics/openAccess Geosciences Multidisciplinary Multidisciplinär geovetenskap Article in journal info:eu-repo/semantics/article text 2022 ftuppsalauniv https://doi.org/10.1002/esp.5456 2023-11-01T23:32:04Z 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 Bonäsheden, 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 Uppsala University: Publications (DiVA) Earth Surface Processes and Landforms 47 14 3276 3301 |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Geosciences Multidisciplinary Multidisciplinär geovetenskap |
spellingShingle |
Geosciences Multidisciplinary Multidisciplinär geovetenskap Stevens, Thomas Sechi, Daniele Tziavaras, Charilaos Schneider, Ramona Banak, Adriano Andreucci, Stefano Hätterstrand, Martina Pascucci, Vincenzo Age, formation and significance of loess deposits in central Sweden |
topic_facet |
Geosciences Multidisciplinary Multidisciplinär geovetenskap |
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 Bonäsheden, 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. |
format |
Article in Journal/Newspaper |
author |
Stevens, Thomas Sechi, Daniele Tziavaras, Charilaos Schneider, Ramona Banak, Adriano Andreucci, Stefano Hätterstrand, Martina Pascucci, Vincenzo |
author_facet |
Stevens, Thomas Sechi, Daniele Tziavaras, Charilaos Schneider, Ramona Banak, Adriano Andreucci, Stefano Hätterstrand, Martina Pascucci, Vincenzo |
author_sort |
Stevens, Thomas |
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 |
publisher |
Uppsala universitet, Luft-, vatten- och landskapslära |
publishDate |
2022 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-480967 https://doi.org/10.1002/esp.5456 |
genre |
Fennoscandia |
genre_facet |
Fennoscandia |
op_relation |
Earth Surface Processes and Landforms, 0197-9337, 2022, 47:14, s. 3276-3301 orcid:0000-0002-6662-6650 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-480967 doi:10.1002/esp.5456 ISI:000842829200001 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1002/esp.5456 |
container_title |
Earth Surface Processes and Landforms |
container_volume |
47 |
container_issue |
14 |
container_start_page |
3276 |
op_container_end_page |
3301 |
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1782334033439490048 |