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A chronology of environmental changes in the Lake Vättern basin from deglaciation to its final isolation

Swärd, Henrik; O'Regan, Matt; Björck, Svante LU ; Greenwood, Sarah L.; Kylander, Malin E.; Mörth, Carl-Magnus; Pearce, Christof and Jakobsson, Martin (2017) In Boreas
Abstract

During and after deglaciation, Lake Vättern developed from a proglacial lake situated at the westernmost rim of the Baltic Ice Lake (BIL), into a brackish water body connecting the North Sea and the Baltic Sea, and finally into an isolated freshwater lake. Here we present geochemical and mineralogical data from a 70-m composite sediment core recovered in southern Lake Vättern. Together with a radiocarbon age model of this core, we are able to delineate the character and timing of the different lake stages. In addition to a common mineralogical background signature seen throughout the sediment core, the proglacial sediments bear a calcite imprint representing ice-sheet transported material from the limestone bedrock that borders the lake... (More)

During and after deglaciation, Lake Vättern developed from a proglacial lake situated at the westernmost rim of the Baltic Ice Lake (BIL), into a brackish water body connecting the North Sea and the Baltic Sea, and finally into an isolated freshwater lake. Here we present geochemical and mineralogical data from a 70-m composite sediment core recovered in southern Lake Vättern. Together with a radiocarbon age model of this core, we are able to delineate the character and timing of the different lake stages. In addition to a common mineralogical background signature seen throughout the sediment core, the proglacial sediments bear a calcite imprint representing ice-sheet transported material from the limestone bedrock that borders the lake basin in the northeast. The proglacial fresh to brackish water transition is dated to 11 480±290 cal. a BP and is in close agreement with other regional chronologies. The brackish period lasted c. 300 years and was followed by a c. 1600 year freshwater period before the Vättern basin became isolated from the Initial Littorina Sea. Decreasing detrital input, increasing δ13C values and the appearance of diatoms in the upper 15 m of the sediment succession are interpreted as an overall increase in biological productivity. This mode of sedimentation continues until the present and is interpreted to mark the final isolation of the lake at 9530±50 cal. a BP. Consequently, the isolation of Lake Vättern was not an outcome of the Ancylus Lake regression, but rather because of ongoing continental uplift in the early Littorina period.

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in
Boreas
publisher
Taylor & Francis
external identifiers
  • scopus:85031670114
ISSN
0300-9483
DOI
10.1111/bor.12288
language
English
LU publication?
yes
id
54387fe4-bb45-452f-8f89-2aaa3ea6723c
date added to LUP
2017-10-31 09:32:08
date last changed
2018-02-18 05:05:02
@article{54387fe4-bb45-452f-8f89-2aaa3ea6723c,
  abstract     = {<p>During and after deglaciation, Lake Vättern developed from a proglacial lake situated at the westernmost rim of the Baltic Ice Lake (BIL), into a brackish water body connecting the North Sea and the Baltic Sea, and finally into an isolated freshwater lake. Here we present geochemical and mineralogical data from a 70-m composite sediment core recovered in southern Lake Vättern. Together with a radiocarbon age model of this core, we are able to delineate the character and timing of the different lake stages. In addition to a common mineralogical background signature seen throughout the sediment core, the proglacial sediments bear a calcite imprint representing ice-sheet transported material from the limestone bedrock that borders the lake basin in the northeast. The proglacial fresh to brackish water transition is dated to 11 480±290 cal. a BP and is in close agreement with other regional chronologies. The brackish period lasted c. 300 years and was followed by a c. 1600 year freshwater period before the Vättern basin became isolated from the Initial Littorina Sea. Decreasing detrital input, increasing δ<sup>13</sup>C values and the appearance of diatoms in the upper 15 m of the sediment succession are interpreted as an overall increase in biological productivity. This mode of sedimentation continues until the present and is interpreted to mark the final isolation of the lake at 9530±50 cal. a BP. Consequently, the isolation of Lake Vättern was not an outcome of the Ancylus Lake regression, but rather because of ongoing continental uplift in the early Littorina period.</p>},
  author       = {Swärd, Henrik and O'Regan, Matt and Björck, Svante and Greenwood, Sarah L. and Kylander, Malin E. and Mörth, Carl-Magnus and Pearce, Christof and Jakobsson, Martin},
  issn         = {0300-9483},
  language     = {eng},
  month        = {10},
  publisher    = {Taylor & Francis},
  series       = {Boreas},
  title        = {A chronology of environmental changes in the Lake Vättern basin from deglaciation to its final isolation},
  url          = {http://dx.doi.org/10.1111/bor.12288},
  year         = {2017},
}