Long-Term Geomorphological Evolution

Abstract

Hungary occupies the inner parts of the largest basin in the Alpine orogenic belt, the Pannonian (Carpathian) Basin. Elements of its present-day topography have taken shape from the Late Paleozoic to modern times. A uniform basement of the basin was amalgamated from terranes of different origin as late as in the Middle Miocene. Accordingly, older landforms had been created on either the European or the African plate, while since the Miocene geomorphic evolution has happened within a common framework. The oldest relict landforms are fragments of multiple generations of tropical planation surfaces (e.g. tower karsts, shallow tropical karsts, tors), which had formed until the Middle Miocene. From the late Neogene other types of landforms have been preserved as well. The Middle to Late Miocene andesitic-rhyolitic volcanism built mountain ranges consisting mainly of stratovolcanoes. From the Pliocene mostly glacis but also pediments formed in the piedmont zones. The Late Miocene–Early Pleistocene basalt volcanoes include a few shield volcanoes and numerous maars. The spatial distribution of recent geomorphic processes is controlled by a compressional stress regime due to basin inversion acting from the end of the Neogene. Mountains and hills are uplifting and being eroded, dissected by incising watercourses. Uplift and climatic oscillations initiated the formation of flights of terraces along rivers. Mass movements are common on slopes. Aeolian processes had increased importance under the periglacial climate of the Pleistocene glacials: an extensive, thick loess cover was deposited, while wind erosion carved mega-yardangs, wind corridors and deflation hollows. Deflated material accumulated in large dune fields active up to the Holocene. Permafrost features are common in the northern and western parts of the basin. The majority of Hungary’s surface is Pleistocene–Holocene alluvial plains.