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Ice-flow patterns and dispersal of erratics at the southwestern margin of the last Scandinavian Ice Sheet: signature of palaeo-ice streams

Kjaer, Kurt LU ; Houmark-Nielsen, M and Richardt, N (2003) In Boreas 32(1). p.130-148
Abstract
An extensive set of proxy-data was acquired from eastern and central Denmark in order to study the dynamic behaviour of the southwestern margin of the last Scandinavian Ice Sheet. We examine the last three glacier advances of the Late Weichselian: the Main advance from central Sweden, representing the maximum ice extent at this time (c. 21-20 ka BP), and the two succeeding Baltic advances (c. 18-15 ka BP). Directional properties from tills and glaciotectonic overprints are used to reveal large-scale flowline patterns. Together with the geomorphological outline of ice margins, flowlines were successively more fan-shaped, indicating that the dependence of the subglacial topography increases as ice advances become younger. It is suggested... (More)
An extensive set of proxy-data was acquired from eastern and central Denmark in order to study the dynamic behaviour of the southwestern margin of the last Scandinavian Ice Sheet. We examine the last three glacier advances of the Late Weichselian: the Main advance from central Sweden, representing the maximum ice extent at this time (c. 21-20 ka BP), and the two succeeding Baltic advances (c. 18-15 ka BP). Directional properties from tills and glaciotectonic overprints are used to reveal large-scale flowline patterns. Together with the geomorphological outline of ice margins, flowlines were successively more fan-shaped, indicating that the dependence of the subglacial topography increases as ice advances become younger. It is suggested that while the ice thickness decreases. more lobate configurations of ice margins are created as a result. Clast-compositional data derived from the fine-gravel fraction in tills are used to reconstruct dispersal patterns of erratic material. The dispersal patterns during the three advances show a gradually diminishing influence of local Pre-Quaternary bedrocks and older glacial deposits, and progressively longer transport distances of far-travelled erratics. We speculate that the principal factor governing this development is a successively decreasing interaction between the ice and its bed, which influences the concentration of erratics. debris comminution processes and the basal ice velocity. We envisage the Main advance from central Sweden as a slow-flowing inter-stream ice body with high bed interaction compared to the succeeding Baltic advances, which we regard to have been rapid flowing ice streams with limited bed interaction. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Boreas
volume
32
issue
1
pages
130 - 148
publisher
Taylor & Francis
external identifiers
  • wos:000182465700009
  • scopus:0038055854
ISSN
1502-3885
DOI
10.1080/03009480310001074
language
English
LU publication?
yes
id
55e7eecf-d6a1-4a7d-a15b-15decafa62c7 (old id 312799)
date added to LUP
2007-09-16 07:56:54
date last changed
2018-10-03 10:57:59
@article{55e7eecf-d6a1-4a7d-a15b-15decafa62c7,
  abstract     = {An extensive set of proxy-data was acquired from eastern and central Denmark in order to study the dynamic behaviour of the southwestern margin of the last Scandinavian Ice Sheet. We examine the last three glacier advances of the Late Weichselian: the Main advance from central Sweden, representing the maximum ice extent at this time (c. 21-20 ka BP), and the two succeeding Baltic advances (c. 18-15 ka BP). Directional properties from tills and glaciotectonic overprints are used to reveal large-scale flowline patterns. Together with the geomorphological outline of ice margins, flowlines were successively more fan-shaped, indicating that the dependence of the subglacial topography increases as ice advances become younger. It is suggested that while the ice thickness decreases. more lobate configurations of ice margins are created as a result. Clast-compositional data derived from the fine-gravel fraction in tills are used to reconstruct dispersal patterns of erratic material. The dispersal patterns during the three advances show a gradually diminishing influence of local Pre-Quaternary bedrocks and older glacial deposits, and progressively longer transport distances of far-travelled erratics. We speculate that the principal factor governing this development is a successively decreasing interaction between the ice and its bed, which influences the concentration of erratics. debris comminution processes and the basal ice velocity. We envisage the Main advance from central Sweden as a slow-flowing inter-stream ice body with high bed interaction compared to the succeeding Baltic advances, which we regard to have been rapid flowing ice streams with limited bed interaction.},
  author       = {Kjaer, Kurt and Houmark-Nielsen, M and Richardt, N},
  issn         = {1502-3885},
  language     = {eng},
  number       = {1},
  pages        = {130--148},
  publisher    = {Taylor & Francis},
  series       = {Boreas},
  title        = {Ice-flow patterns and dispersal of erratics at the southwestern margin of the last Scandinavian Ice Sheet: signature of palaeo-ice streams},
  url          = {http://dx.doi.org/10.1080/03009480310001074},
  volume       = {32},
  year         = {2003},
}