| Summary: | Summary: This is a studie of Holocene lake sediments. The investigated lake, Vuolep Njakajaure (68°20'N, 18°47'O) is situated in the Abisko valley in the northern parts of the Caledonides. In this study four marginal cores of nonlaminated algalgyttja have been studied with respect to magnetic concentration parameters (ie susceptibility(χ) and SIRM) and loss on ignition. Core correlations have been carried out based on SIRM/χ and S-ratio. The core correlations indicates a hiatus at the beginning of Holocene in two of the cores. One core was selected as a main core. This main core was analysed with respect to pollen composition and indirectly 14C-dated by correlation to Sonesson (1968). Thus the sedimentation-rates were calculated in all of the cores. Snowball (1993) has shown that the S-ratio can be an indicator to climatic changes, because dissolution of magnetitegrains is greater compared to hematite-grains during warmer periods. S-ratio and SIRM/χ where compared to the climatic changes, as described by the pollenzonation, in the main core to investigate if they reflect climatic changes. In the upper part of the main core a correlation of the climatic changes and the mineral magnetic parameters was found. This is a strong indicator to high representativity of climatic changes, because two independent parameters ie pollen and magnetics correlates. Populärvetenskaplig sammanfattning: Detta är en studie av Holocena sjösediment. Den undersökta sjön, Vuolep Njakajaure (68°20'N, 18°47'O) ligger i Abiskodalen i de norra delarna av Kaledoniderna. I denna studie har fyra borrkärnor av alggyttja jämförts med magnetiska analyser (susceptibilitet(χ), SIRM) och glödförlust. Borrkärnorna har korrelerats i huvudsak baserat på SIRM/χ och S-kvot. Korreleringarna indikerar en hiatus i början av Holocen i två av borrkärnorna. En av borrkärnorna valdes till huvudborrkärna och i den analyserades pollensammansättningen. Huvudborrkärnan 14C-daterades indirekt genom korrelering till Sonesson (1968). Därefter beräknades ...
|
|---|