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Marginal formation of De Geer moraines and their implications to the dynamics of grounding-line recession

Lindén, Mattias LU and Möller, Per LU (2005) In Journal of Quaternary Science 20(2). p.113-133
Abstract
De Geer moraine ridges occur in abundance in the coastal zone of northern Sweden, preferentially in areas with proglacial water depths in excess of 150 m at deglaciation. From detailed sedimentological and structural investigations in machine-dug trenches across De Geer ridges it is concluded that the moraines formed due to subglacial sediment advection to the ice margin during temporary halts in grounding-line retreat, forming gradually thickening sediment wedges. The proximal part of the moraines were built up in submarginal position as stacked sequences of deforming bed diamictons, intercalated with glaciofluvial canal-infill sediments, whereas the distal parts were built up from the grounding line by prograding sediment gravity-flow... (More)
De Geer moraine ridges occur in abundance in the coastal zone of northern Sweden, preferentially in areas with proglacial water depths in excess of 150 m at deglaciation. From detailed sedimentological and structural investigations in machine-dug trenches across De Geer ridges it is concluded that the moraines formed due to subglacial sediment advection to the ice margin during temporary halts in grounding-line retreat, forming gradually thickening sediment wedges. The proximal part of the moraines were built up in submarginal position as stacked sequences of deforming bed diamictons, intercalated with glaciofluvial canal-infill sediments, whereas the distal parts were built up from the grounding line by prograding sediment gravity-flow deposits, distally interfingering with glaciolacustrine sediments. The rapid grounding-line retreat (ca. 400 m yr(-1)) was driven by rapid calving, in turn enhanced by fast iceflow and marginal thinning of ice due to deforming bed conditions. The spatial distribution of the moraine ridges indicates stepwise retreat of the grounding line. It is suggested that this is due to slab and flake calving of the ice cliff above the waterline, forming a gradually widening subaqueous ice ledge which eventually breaks off to a new grounding line, followed by regained sediment delivery and ridge build-up. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
deforming bed, subaqueous deglaciation, De Geer moraines, glacial sedimentology, grounding line
in
Journal of Quaternary Science
volume
20
issue
2
pages
113 - 133
publisher
John Wiley & Sons
external identifiers
  • wos:000227618100002
  • scopus:14944354025
ISSN
1099-1417
DOI
10.1002/jqs.902
language
English
LU publication?
yes
id
cac1de06-781e-4007-a48f-a511f588419a (old id 249906)
date added to LUP
2007-08-20 08:12:24
date last changed
2017-07-09 04:16:48
@article{cac1de06-781e-4007-a48f-a511f588419a,
  abstract     = {De Geer moraine ridges occur in abundance in the coastal zone of northern Sweden, preferentially in areas with proglacial water depths in excess of 150 m at deglaciation. From detailed sedimentological and structural investigations in machine-dug trenches across De Geer ridges it is concluded that the moraines formed due to subglacial sediment advection to the ice margin during temporary halts in grounding-line retreat, forming gradually thickening sediment wedges. The proximal part of the moraines were built up in submarginal position as stacked sequences of deforming bed diamictons, intercalated with glaciofluvial canal-infill sediments, whereas the distal parts were built up from the grounding line by prograding sediment gravity-flow deposits, distally interfingering with glaciolacustrine sediments. The rapid grounding-line retreat (ca. 400 m yr(-1)) was driven by rapid calving, in turn enhanced by fast iceflow and marginal thinning of ice due to deforming bed conditions. The spatial distribution of the moraine ridges indicates stepwise retreat of the grounding line. It is suggested that this is due to slab and flake calving of the ice cliff above the waterline, forming a gradually widening subaqueous ice ledge which eventually breaks off to a new grounding line, followed by regained sediment delivery and ridge build-up.},
  author       = {Lindén, Mattias and Möller, Per},
  issn         = {1099-1417},
  keyword      = {deforming bed,subaqueous deglaciation,De Geer moraines,glacial sedimentology,grounding line},
  language     = {eng},
  number       = {2},
  pages        = {113--133},
  publisher    = {John Wiley & Sons},
  series       = {Journal of Quaternary Science},
  title        = {Marginal formation of De Geer moraines and their implications to the dynamics of grounding-line recession},
  url          = {http://dx.doi.org/10.1002/jqs.902},
  volume       = {20},
  year         = {2005},
}