Dr. Fűköh Levente szerk.: Malakológiai Tájékoztató 27. (Eger, 2009.)
SÁNDOR, R.-SÜMEGI,P.: New preliminary data for evolution of the Holocene Hungarian Mollusc fauna
New preliminary data for evolution of the Holocene Hungarian Mollusc fauna R. Sándor & R Sümegi Abstract: The article introduce the examination of the malacological material of Late Quaternary sediments carried out from Red Marsh at Császártöltés during the past couple of years. Key words: Red Marsh, Danube valley, Holocene, Hungary The Vörös-mocsár (Red Marsh) is a southern unit of the mire system of the Danube-Tisza Interfluve running south in the former watercourse of the river Danube. This marsh developed in a filled up river channel and it is situated at the border of two significantly different regions (Solti Plain and Sand Dune Region) on the analysed area. The Solti Plain belonging to the Danube floodplain is covered with the network of abandoned watercourses of the river Danube. The Solti Plain and the adjoining Sand Dune Region of the Danube-Tisza Interfluve are separated by an approximately 10 meters high, steep loessy high-bluff. The natural vegetation of the sand and loess covered high-bluff was Junipero-Populetum scrub and sandy grasslands, formed by Bromus squarrosus, Secale sylvestre, Stipa borystenica and Festuca vaginata. Well-drained areas were occupied by oak forests (Iridi variegataeQuercetum roboris, Polygonato latifolii-Quercetum roboris). Recently most of the area is cultural landscape with ploughlands and vineyards and some patches of natural vegetation. The Solti Plain was a widespread peatland with patches of Fraxino pannonicae-Alnetum forests. Water regulations started in 1873 destroyed the original vegetation of this peatland. The artificial Danube Basin Channel, finished in 1929, drained the mires. Only some patches of the natural vegetation survived. After the water regulations peat-cutting altered the landscape. Most areas of the Red Marsh were destroyed by peat-cutting. Nowadays the peatlands are covered with secondary vegetation: meadows, reed-swamps and sedgeswamps. Some cores were retrieved using a five cm diameter Russian corer, but only one core contained mollusc shells, therefore malacological analysis was made only on this 280 cm deep undisturbed core sequence. This sediment sequence was used for plant macrofossil (Jakab, G. 2005), pollen and geochemical analyses. Detailed description of the peat core follows the system described by Troels-Smith (1955). Some radiocarbon dating of the sequence was obtained by both bulk and AMS analyses. The core was divided into 4 cm samples. The organic content of the core samples were estimated by loss-on-ignition at 550 °C for 5 hours and the carbonate content by the further loss-on-ignition at 900 °C for 5 hours. A sequential extraction method with a long established history in the analysis of geochemical composition of lacustrine and peat sediments was adopted in our work. Mollusc fauna inwashed from sediment using by sieves with 0.5 mm diameter. More than 2000 specimens belonging to 37 species have come to light from the core.
