OSL Dating and Grain Size Analysis: A Case Study in Brattforsheden and the Siljan Area in Central Sweden

• Main Author: Charilaos, Tziavaras
• Format: Bachelor Thesis
• Language: English
• Published: Uppsala universitet, Institutionen för geovetenskaper 2020
• Subjects: Physical Geography; Naturgeografi; Fennoscandian; Ice Sheet
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-404071

The geomorphological evolution of areas in Central Sweden after their deglaciation from the Fennoscandian Ice Sheet (FeIS) retreat has been a topic of study in the past, with more extensive work being done the more recent years. It is assumed that the FeIS retreat produced big quantities of fine material, which then could be deposited in the newly exposed areas. The main focus so far has been given on sand dune activity for the areas of Brattforsheden and the Siljan. But in this study on the areas of Brattforsheden and the Siljan, sites with presumed silty material have been targeted, to establish a deposition chronology and also acquire more precise information regarding the consistency of these deposits through grain size analysis. The dating and grain size results from the Siljan area site seem to confirm the existing theories regarding dust transport in this area. In Gräshöjden which is located in Brattforsheden the age results show dust transport significantly after the deglaciation. That contradicts the estimated time that dust transport stopped from recent studies. For further support on this, the grain size results suggest fine sand activity in the area. Finally, the grain size results from the Finnhöjden site show a sandy base that was topped by a coarse silty layer. The focus on the silty layers of these areas seem to be fruitful and essential in understanding the dust patterns and durations for the period after the deglaciation. The grain size results suggest typical loess deposition on the sites of Finnhöjden and Hökberg, whereas in Gräshöjden the deposits have a significant influence of sand. The ages in Gräshöjden extend from approximately 8-5 ka with the uncertainty ranges whereas the Hökberg sediments were deposited from 12-10 ka. More sites should be examined to be more certain and make sure these results can be representative for larger regions of Brattforsheden and Siljan. Den geomorfologiska utvecklingen av områden i Mellansverige efter deglaciationen från Fennoskandiska inlandsisen (FeIS) ...