Viola T. Dobosi: Paleolithic Man in the Által-ér Valley (Tata, 1999)

polar regions became thicker continuously and extended towards the south while the permanent snow limit of the high mountains descended. Finally, about one third of the Earth was covered by terrestrial ice cover and a giant sheet of ice of glacier „rivers", moving several centimetres a day. According to the estimations, during the greatest glaciation, an ice cover of approximately 45 million square kilometres used to cover mountains and valleys, at some places reaching the thickness of 2 km. Today the territories covered by ice are extended to not more than 15 million square kilometres. That is why we call this period „Ice Age". On the place of today's taiga forests composed of pine and oak forests with exuberant foliage, there were ice planed waste-lands or, to the south of it, tundra covered by peat mosses and alpine vegetation, scrubby bushes, scroggy birches, polar willows and scarce groves of pine trees struggling for their survival like the Lapp-land of our days, covered by pioneer lichens and small mosses, housing animals that live in our days only on the alpine and arctic tundra. The water of the ocean dwindled away, the water level was lowered occasionally by several hundred meters. The areas with shallow water run dry because the water evaporated did not get back to the sea but remained in the form of solid snow and ice on the mainland. " The Ice Age can be divided into several periods of glaciation and intermittent warmer periods lasting for several thousand and tenthousand years each. For the division of the phases, several systems of names were used based mainly on locality names, calling each phase after a site where typical sediments and features were observed from the given period. In Hungary we also have local names to the climatic phases; however, typically the names generally used in Central Europe are used - at least, understood - universally. These names are considered as the same and related to cover the same period which is not always the case for a local nomenclature. The phases of glaciation generally used in Central Europe are named after tributaries of the Danube originating in the Alps and a small lake, respectively. The glaciations are labelled G M R W, i.e., Günz, Mindel, Riss, Wurm, while the interim phases are marked as G/M, M/R and R/W. This double rhythm of changing climate, however, was also subjected to minor changes, lasting for some hundred or thousand years. These anomalies of the climate could and in fact did change the life-style and life rhythm of human communities. Similar to the geological present, the Holocene period (which is nothing else but a period between glaciations, a so-called interglacial) even during the history of humanity documented by written sources we can come across unusual periods of climate (e.g. the famous „small ice age" of the Middle Ages, the social and politi11