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Was southern Sweden ice free at 19-25 ka, or were the post LGM glacifluvial sediments incompletely bleached?

Alexanderson, Helena LU and Murray, Andrew S. (2007) In Quaternary Geochronology 2(1-4). p.229-236
Abstract
Glacifluvial deposits along an ice-marginal zone,in Smaland, southern Sweden, have been dated using post-IR blue OSL. To test for incomplete bleaching, we adopted two strategies: analysis of modern analogues and small-aliquot dose distributions. Samples of modern fluvial sediments show no significant incomplete bleaching; they yield equivalent doses of only 0.5-2 Gy (similar to 0.25-4% of our glacifluvial sediment doses). Small-aliquot dose distributions do not provide any evidence for incomplete bleaching. The sediments are believed to have been deposited during deglaciation and appear to fall into two age groups: 19-25 ka (mainly sandur sediments) and 33-73 ka (mainly deltaic sediments). Compared to the expected ages (13-15 ka), even the... (More)
Glacifluvial deposits along an ice-marginal zone,in Smaland, southern Sweden, have been dated using post-IR blue OSL. To test for incomplete bleaching, we adopted two strategies: analysis of modern analogues and small-aliquot dose distributions. Samples of modern fluvial sediments show no significant incomplete bleaching; they yield equivalent doses of only 0.5-2 Gy (similar to 0.25-4% of our glacifluvial sediment doses). Small-aliquot dose distributions do not provide any evidence for incomplete bleaching. The sediments are believed to have been deposited during deglaciation and appear to fall into two age groups: 19-25 ka (mainly sandur sediments) and 33-73 ka (mainly deltaic sediments). Compared to the expected ages (13-15 ka), even the younger glacifluvial OSL ages appear up to 10 000 years (similar to 25 Gy) too old. The ages are nevertheless stratigraphically consistent and correspond between sites; we deduce that the 19-25 ka ages are true deposition ages. For glacifluvial sedimentation to take place on the South Swedish Upland at this time either a very early deglaciation is required, or alternatively ice-free conditions just prior to the LGM. The deltaic sediments (33-73 ka) were most likely not significantly bleached during deposition and thus they date events prior to the latest ice advance. (c) 2006 Elsevier Ltd. All rights reserved. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
OSL, glacifluvial, Sweden, Weichselian
in
Quaternary Geochronology
volume
2
issue
1-4
pages
229 - 236
publisher
Elsevier
external identifiers
  • wos:000247210000038
  • scopus:34548059254
ISSN
1871-1014
DOI
10.1016/j.quageo.2006.05.007
language
English
LU publication?
no
id
eec50c2f-2c7e-4e25-8190-f30626ae54b4 (old id 4450058)
date added to LUP
2014-05-26 09:29:16
date last changed
2017-10-22 04:30:46
@article{eec50c2f-2c7e-4e25-8190-f30626ae54b4,
  abstract     = {Glacifluvial deposits along an ice-marginal zone,in Smaland, southern Sweden, have been dated using post-IR blue OSL. To test for incomplete bleaching, we adopted two strategies: analysis of modern analogues and small-aliquot dose distributions. Samples of modern fluvial sediments show no significant incomplete bleaching; they yield equivalent doses of only 0.5-2 Gy (similar to 0.25-4% of our glacifluvial sediment doses). Small-aliquot dose distributions do not provide any evidence for incomplete bleaching. The sediments are believed to have been deposited during deglaciation and appear to fall into two age groups: 19-25 ka (mainly sandur sediments) and 33-73 ka (mainly deltaic sediments). Compared to the expected ages (13-15 ka), even the younger glacifluvial OSL ages appear up to 10 000 years (similar to 25 Gy) too old. The ages are nevertheless stratigraphically consistent and correspond between sites; we deduce that the 19-25 ka ages are true deposition ages. For glacifluvial sedimentation to take place on the South Swedish Upland at this time either a very early deglaciation is required, or alternatively ice-free conditions just prior to the LGM. The deltaic sediments (33-73 ka) were most likely not significantly bleached during deposition and thus they date events prior to the latest ice advance. (c) 2006 Elsevier Ltd. All rights reserved.},
  author       = {Alexanderson, Helena and Murray, Andrew S.},
  issn         = {1871-1014},
  keyword      = {OSL,glacifluvial,Sweden,Weichselian},
  language     = {eng},
  number       = {1-4},
  pages        = {229--236},
  publisher    = {Elsevier},
  series       = {Quaternary Geochronology},
  title        = {Was southern Sweden ice free at 19-25 ka, or were the post LGM glacifluvial sediments incompletely bleached?},
  url          = {http://dx.doi.org/10.1016/j.quageo.2006.05.007},
  volume       = {2},
  year         = {2007},
}