Reconstructing the Paleoenvironmental Evolution of Lake Kolon (Hungary) through Integrated Geochemical and Sedimentological Analyses of Quaternary Sediments

Lake Kolon (Hungary), situated in the middle of the Turjánvidék area between the saline lakes of the Danube valley and the Homokhátság, is one of the most significant natural aquatic habitats in the Danube–Tisza Interfluve region. The central question of this study is how the lake changed, and how environmental factors and human activities have influenced these paleoenvironmental changes in Lake Kolon. A multiproxy analysis of a core sequence (loss on ignition, grain size, magnetic susceptibility, and geochemistry) provided crucial insights. Notably, correlations are observed in the following relationships: (1) clay, organic matter, and elements derived from organic sources, such as Na, K, and Zn; (2) MS, sand, inorganic matter, and elements originating from inorganic sources, such as Fe, Al, Ti, Na, K, and P; and (3) carbonate content and elements originating from carbonate sources, such as Ca and Mg. The lake’s paleoenvironment underwent significant changes in the past 27,000 years. Late-Pleistocene wind-blown sand provided the bottom for an oligotrophic lake (17,700 BP), followed by a calcareous mesotrophic Chara-lake phase (13,800 BP). Peat accumulation, along with the eutrophic lake phase, began at the Pleistocene–Holocene boundary around 11,700 BP. From 10,300 BP, with the emergence of an extended peatland phase, the percentage of organic matter (peat) increased significantly. Anthropogenic changes occurred from around 9000–8000 BP due to the different emerging cultures in the Carpathian basin, and from 942–579 BP due to the Hungarian settlements and activity nearby, respectively.