Menu

Javascript is not activated in your browser. This website needs javascript activated to work properly.
You are here

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

Author:
  • Helena Alexanderson
  • Andrew S. Murray
Publishing year: 2007
Language: English
Pages: 229-236
Publication/Series: Quaternary Geochronology
Volume: 2
Issue: 1-4
Document type: Journal article
Publisher: Elsevier

Abstract english

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.

Keywords

  • Geology
  • OSL
  • glacifluvial
  • Sweden
  • Weichselian

Other

Published
  • ISSN: 1871-1014
Helena Alexandersson
E-mail: helena [dot] alexanderson [at] geol [dot] lu [dot] se

Professor

Quaternary Sciences

+46 46 222 44 83

435

16

Aeolian sand project

Project members
Members of the aeolian sand project: Martin Bernhardson, Sara Florén, Edyta Kalińska-Nartiša and Helena Alexanderson.

Read more about the project here.