Glaciotectonic Structures in Central Sweden and their Significance for Glacial Theory
Various glaciotectonic structures and landforms created by ice pushing are common in drift and interstadial sediments in a narrow belt of central Sweden. Described examples from the Lake Storsjôn vicinity demonstrate that glaciotectonic deformation took place while the area was deeply covered by the...
| Published in: | Géographie physique et Quaternaire |
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| Main Authors: | , |
| Format: | Text |
| Language: | English |
| Published: |
Les Presses de l'Université de Montréal
1988
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| Subjects: | |
| Online Access: | http://id.erudit.org/iderudit/032739ar https://doi.org/10.7202/032739ar |
| Summary: | Various glaciotectonic structures and landforms created by ice pushing are common in drift and interstadial sediments in a narrow belt of central Sweden. Described examples from the Lake Storsjôn vicinity demonstrate that glaciotectonic deformation took place while the area was deeply covered by the last Fennoscandian Ice Sheet. Deformation was controlled by pressure gradients related to position of the ice divide and ice movement away from the divide. As the position of the divide shifted during the last glaciation, so did the orientation of glaciotectonic structures. The regional distribution of glaciotectonic features in Fennoscandia falls into three zones: (1) inner zone of widespread, small- to moderate-sized features in older drift, (2) intermediate zone of small, isolated features in drift of the last glaciation, and (3) outer zone with all manner of large and small features in drift and soft bedrock. These zones are the cumulative results of multiple glaciations and reflect the overall distribution of deformable sediment and bedrock within the continental substratum. Diverses structures glaciotectoniques et formes engendrées par la poussée des glaces sont courantes dans les dépôts glaciaires et les sédiments interstadiaires d'une étroite zone du centre de la Suède. La description de certains exemples observés dans les environs du lac Storsjôn démontre que des déformations glaciotectoniques se sont produites pendant que la région était profondément enfouie sous le dernier inlandsis finnoscandien. Les déformations étaient commandées par le gradient de pression en relation avec la position de la ligne de partage glaciaire et le mouvement des glaces en direction opposée de cette ligne. Au cours de la dernière glaciation, l'orientation des structures glaciotectoniques s'est déplacée en même temps que la ligne de partage des glaces. En Finnoscandinavie, les structures glaciotectoniques se répartissent en trois zones: 1) une zone interne où les éléments de petite à moyenne tailles abondent dans des dépôts ... |
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