Understanding modern and past sedimentary processes in selected lakes from the High Arctic and the Mediterranean realm

• Main Author: Francke, Alexander
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2014
• Subjects: ddc:550; Arctic; Siberia
• Online Access: https://kups.ub.uni-koeln.de/5583/; https://kups.ub.uni-koeln.de/5583/1/Francke_Diss.pdf

Lacustrine sediment sequences can provide valuable archives of past environmental and climatological variability in terrestrial realms. In order to unravel the history of a lake and of a lake’s catchment, a profound understanding of the sedimentary processes is required. This encompasses the supply of allochthonous organic matter, nutrients and clastic material to the lake, the subsequent redistribution within the lake as well as autochthonous organic matter and mineral deposition. These lake internal and external processes are closely linked to the environmental and climatological settings in the specific area and can be reconstructed by using geophysical and sedimentary data. Within the scope of this thesis, modern and past sedimentary processes of selected lakes from the High Artic (Lake El’gygytgyn, NE Siberia) and the Mediterranean Realm (lakes Dojran and Ohrid, Balkan Peninsula) were analyzed by using various datasets and analytical methods. The obtained information about variations in the lakes’ internal and external processes were subsequently used for paleoenvironmental and -climatological reconstructions in the respective area. At Lake El’gygytgyn, modern sedimentary processes were investigated by using geochemical, grain-size and mineralogical data from source rocks, inlet streams and surface sediments. The obtained informa- tion about modern sedimentary processes improved the understanding of hydro-acoustic and downhole logging data, as well as of variations in the granumoleric, geochemical and physical properties of core 5011-1 which covers the entire lacustrine succession of the 3.58 Ma year old Lake El’gygytgyn. Surface samples and downcore data were analyzed by using statistic methods such as Principal Component Analysis (PCA), Redundancy Analysis (RDA), Time Series Analysis and Cluster Analysis. At Lake Dojran, hydro-acoustic data and sediment properties (water content, OM, calcite (CaCO3) content, sulfur content, grain-size, XRF scanning, δ18Ocarb, δ13Ccarb, δ13Corg) of a 7m long sequence were ...