Scientific publications

New palaeogeographic data for the period from the Allerød (~11800 yrs. B. P.) until present were obtained for the Tolvojarvi landscape reserve (LR), situated in the south-west of Karelia, at the border with Finland. Studies of the lacustrine-paludal deposits from Tolvosuo mire by the stratigraphic, radiocarbon, and palaeobotanical methods have helped to update and specify the reconstructions of upland vegetation dynamics produced previously based on a Skopolinoye mire core. The studies also employed data on surface spore-pollen spectra from various plant communities of Tolvojarvi LR mires and forests (their percentage reported in the articles), as well as “correction factors” for woody pollen calculated for surface spore-pollen spectra from mires of Karelian middle taiga. The “marker spores” method was used to avoid bias in reconstructing the Lake Glacial and Early Holocene plant cover. Based on a synthesis of newly and previously obtained palaeogeographic data, the climate-chronological sequence of Late Glacial-Holocene upland vegetation was produced. A comparison of the chronostratigraphy of the studied sections and identification data on Pediastrum algae, pollen, spores, and macrofossils of aquatic and wetland plants revealed some specific features in the development history of the two palaeo-waterbodies and the subsequent formation of Skopolinoye and Tolvosuo mires, as well as enabled reconstructions of wetland vegetation successions at the sampling locations. According to the findings, the water level in the former dropped ~ 10300 yrs. B. P, and in the latter 9300 yrs. B. P. In Tolvosuo, which has a deeper basin, sapropel, mesotrophic and ombrotrophic peat deposition started some 1000 years later. Yet, it managed to form a thicker (55 cm more) peat deposit in less time owing to a somewhat higher (by 0.15 mm/yr.) deposition rate.