Geotechnical and sedimentary evidence for thick-grounded ice in southern Lake Vättern during deglaciation
Number of Authors: 5
2016 (English)In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 138, no 2, 355-366 p.Article in journal (Refereed) Published
A 74-meter Late Pleistocene to Holocene sedimentary sequence was recovered from southern Lake Vattern in the autumn of 2012. At approximate to 54m below the lake floor, shear strength and high-resolution bulk density measurements suggest the presence of an unconformity in the varved proglacial clays. Incremental load consolidation tests reveal highly overconsolidated sediments below this level. Preconsolidation pressures for the underlying sediments are between 1250 and 2100kPa, up to approximate to 1700kPa more than the current in-situ effective stress. The highly overconsolidated sediments indicate either substantial erosion (the removal of 215-360m of sediment), or consolidation under a large grounded ice mass sitting up to 230m above paleo-lake level. Glaciotectonic deformation in underlying sediments supports the interpretation of a grounded ice mass. It is likely that this horizon is either contemporaneous with or older than the Levene moraine, formed between 13.4 and 13.8ka. In the approximate to 30m of overlying proglacial clays, there is no further evidence for grounded ice, indicating that any ice advance to southern Lake Vattern during the Younger Dryas would have been limited to an extremely thin ice tongue.
Place, publisher, year, edition, pages
2016. Vol. 138, no 2, 355-366 p.
Lake Vättern, Deglaciation, Ice sheet, Overconsolidation
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:su:diva-132413DOI: 10.1080/11035897.2015.1055511ISI: 000379763500007OAI: oai:DiVA.org:su-132413DiVA: diva2:952271