ICE AGE RELICT SPHAGNUM PEATS IN CENTRAL EUROPE

The age of the formation of two peat bogs of Kelemér region, NE Hungary, (Kis-Mohos and Nagy Mohos) based on radiocarbon dates – contrary to the previously supposed 10.000 and 5.000 years by Zólyomi – was revealed to be 25.000 and 15.000. According to three new cores a clay-rich layer almost devoid of macrofossils between 2.7-3.0 m got probably into the southern basin of Nagy Mohos at the time of the formation of Kis-Mohos by a landslide and one can find a further 2.6 m thick pleistocene peat sediment underneath. At the Kis-Mohos basin between 3-4 m depths there is a solid deposit rich in charcoal fragments and pebbles about which Zólyomi suspected to be the base of the sediment. Underneath that layer others have found a further 4 m thick moss and meadow peat layer where a further 2 m deep Late-glacial lacustrine sediment was deposited. The layer which was previously assumed by Zólyomi to be the base slided into the basin by erosion caused by the severe forest clearance via burnings by the Celtic tribes in the region. The rise in the water level during Medieval times was probably caused by the artificial barrage of the watercover of the bog. The southern basin of Nagy-Mohos was refilled mostly by swamp layers during the Würm interstadial. The surface flora of the bog was possibly highly mosaic-like with some open-water patches. During the Upper-Würm microinterstadials with more moderate and more humid climate, a transitional sphagnum peat bog was formed at least 2 times on the bog surface and several Bryophyte species and plants still living on the peat-bog appeared that time. The Bryophyte analyses of the Pleistocene layers of Nagy-Mohos showed the presence of such arctic and boreal peat-bog assemblages, whose recent analogues can be found at the Northern part of Eurasia and previous Bryophyta analyses performed on Hungarian Upper Pleistocene peat profiles did not revealed and were until now unknown in the Carpathian-basin. We can assume on the basis of the analysis of the radiocarbon dated sediments of Nagy-Mohos peat-bog that one of the refugial territories of several species forming also the recent bogs of the North-American and North Eurasian peat-bog territories, being under icesheet cover during the Würm period, covering recently several million km, developed in the two Mohos basins of the Kelemér region.