Hidrológiai Közlöny 2008 (88. évfolyam)
6. szám - IL. Hidrobiológus Napok: „A Balaton és vízrendszere – a Balaton-kutatás története” és „A Duna-kutatás története” Tihany, 2007. október 3–5.
42 HIDROLÓGIAI KÖZLÖNY 2008. 88. ÉVF. 6. SZ. PLEISZTOCÉN IDEJÉN Mezotróf állapot ||||||| Eutróf állapot Mezo-Eutróf állapot HOLOCÉN IDEJÉN S3 Mező-Eutróf állapot ül Eulróf áll aP° l IV. 10.000-9.000 év BP (Pinus-Betula) L V. 9 000-7 500 év BP (Corylus) I.b. 13.300-12.400 év BP (Bölling) Vl-VIl 7.600-5.100 év BP (Quercus) Vili-IX.-X. 5.100 év BP-napjainkig (Quercus-Fagus, Fagus. Cultivated max. elterjedés 0 5 10 km 2. ábra. A vízborítás és a vízminűség változása a pleisztocén és a holocén során Irodalom Birks, B.J. and Birks, H.H. 1980: Quaternary Palaeoecology. - Edward Arnold, London Cserny T. (1993): Lake Balaton, Hungary. In Gierlowski-Kordesch and Kelts (eds): A Global Geological Record of Lake Basins, Cambridge University Press. - pp. 397-401. Cserny T., Nagy-Bodor E. (2000): Limnogeological investigations on Lake Balaton. In: Gierlowski-Kordesch, E. and K. Kelts (eds): Lake Basins Through Space and Time, AAPG Studies in Geology 46, pp. 605 - 618. Cserny T. (2002): A balatoni negyedidőszaki üledékek kutatási eredményei, Földtani Közlöny 132/különszám, Budapest, pp. 193-213 Nagy-Bodor E., Cserny T. (1998): A balatoni öblök vizborítottságánakfejlődéstörténete a palynológiai vizsgálatok eredményei alapján. ~ Hidrológiai Közlöny 78. 1998/5-6., pp. 360-363. Nagyné Bodor E., Szurominé Korecz A. (2000): A Balaton negyedkori üledékeinek sporomorpha és ostracoda eredményei. Földtani Közlöny 132/különszám, Budapest, pp. 215-229. Tullner T., Cserny T. (2003): New aspects of lake level changes: Lake Balaton, Hungary. Acta Geologica Hung, Vol. 46/2, pp. 215-238. Tullner, T. - Cserny, T. (2004): A Balaton földtudományi adatbázisa, MAFI Évi Jel. 2002-ről, pp. 47-53. Zólyomi B 1987: Degree and rate of sedimentation in Lake Balaton. In Pécsi, M. (Ed.): Pleistocene environment in Hungary. Contribution of the INQUA Hungarian National Committee to the Xllth INQUA Congress Ottawa, Canada 1987, pp. 57-79. Zólyomi B. 1995: Opportunities for Pollen Stratigraphic Analysis of Shallow Lake Sediments: the Example of Lake Balaton.- Geojournal 36.2/3, pp. 237-241. Results of the geological investigation of Lake Balaton Cserny, T.- Nagyné Bodor, E.- Tullner, T. bstract: The Geological Institute of Hungary has continuously taken part in the solution of environmental problems and tasks of the catchment area of Lake Balaton. The objective set by the integrated geological investigations of the lake was to determine: (1) the time as well as climatic and hydrological conditions of the lake's formation, (2) the history of the lake's inundation, (3) the changes in water level and quality (trophic history) and (4) the velocity of the lake's filling with sediments. Through the integrated interpretation of the results of complex geological (sedimentological, mineralogic-petrological, geochemical, paleontological and isotopic research of boreholes in the lake mud) and geophysical (seismic) investigations the answers were received to the above questions. The main results can be summarised as follows: Lake Balaton formed between 15.000 and 17.000 years BP following the last Pleistocene glacial period as a result of warming climate and increasing precipitation, making up several separated lakes with clear and cool water. Inundation of the lake with precipitation as well as subsurface water (groundwater and karstwater) proceeded progressively from west to east. As a result of increasing water level and the erosion of separating dams inundation of the whole present lake area occurred not before the beginning of the Subboreal period (cca. 5.100 years BP.). Water level and trophity changed frequently as a function of temperature and precipitation. Water quality changed mainly between mesotrophic and meso-eutrophic and it has not become eutrophic for longer periods. The average thickness of the Quaternary sediments of Lake Balaton is 5 m. It varies considerably in the lake as a result of the changing morphology of the lake bed. Formation of lacustrine sediments can be divided in two main periods. The first one lasted up to the beginning of Holocene (10.300 years BP.) and it was characterised the predomination of clastic sedimentation and the formation of peat bogs. The second period starting at the beginning of Holocene and lasting still today can be described essentially by the sedimentation of clayey calcareous mud through chemical precipitation. As a result of radiocarbon dating of lacustrine sediments in borehole samples and related thickness data the velocity of sedimentation can be assessed between 0,38-0,48 mm/year for the whole sedimentary sequence, but this value rises toward the upper part of the profile and it can even reach 10 mm/year in Keszthelyand some other protected bays along the northern lake shore. Keywords: Formation of Balaton, evolution history of inundation and water quality, lake sedimentation, lacustrine sediment. min. elterjedés
