Magnetic susceptibility in sediment records of Lake Ådran,eastern Sweden: correlation among cores and interpretation |
| |
| Authors: | Per Sandgren Jan Risberg Roy Thompson |
| |
| Institution: | (1) Department of Quaternary Geology, Tornavägen 13, S-223 63 Lund, Sweden;(2) Department of Quaternary Research, Odengatan 63, S-113 22 Stockholm, Sweden;(3) Department of Geophysics, University of Edinburgh, EH9 3JZ Edinburgh, Scotland |
| |
| Abstract: | Magnetic susceptibility was used to test the representativity of the lithostratigraphy of a master sediment sequence from Lake Ådran, eastern Sweden. Five further sediment cores from the same lake were correlated and compared with the master sequence using magnetic susceptibility records. Mineral magnetic correlations are generally based on matching prominent susceptibility features but may be significantly improved by using slot sequence analyses. The result of these analyses show that the sediment in the Lake Ådran master sequence can be considered representative for the basin. The variations in the magnetic susceptibility in relation to pollen and diatom analyses also seem to reflect water level changes and shore displacement in the Baltic between 9900 14C years B.P. and the isolation at 5900 14C years B.P. The first emergence of scattered non-vegetated islands is characterised by high susceptibility values. Along with a continuous water lowering and the development of the vegetation during the Ancylus fresh water stage, susceptibility values gradually decrease. A rapid phase of the Ancylus regression between 9200 and 9000 14C years B.P. is seen as an increase in magnetic susceptibility. During the following Baltic brackish water stage, the Litorina stage, susceptibility values are at their lowest, followed by higher values at the isolation from the Baltic with a maximum around 5000 14C years B.P.Shore displacement between 9900 and 5900 14C years B.P. is discussed based on the magnetic susceptibility measurements and their relationship to the pollen and diatom analyses. |
| |
| Keywords: | Holocene sediments magnetic susceptibility slot sequence calculations core correlation Ancylus stage Litorina stage |
| 本文献已被 SpringerLink 等数据库收录！ |
|
