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Incision of a river curvature due to exhumed Miocene volcanic landforms: Danube Bend, Hungary |
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| Authors: | D Karátson K Németh B Székely Zs Ruszkiczay-Rüdiger Z Pécskay |
| Institution: | 1. Department of Physical Geography, E?tv?s University, Pázmány P. sétány 1/c, 1117, Budapest, Hungary 2. Hungarian Geological Institute, Stefánia út 14, 1143, Budapest, Hungary 7. Soil and Earth Sciences, Institute of Natural Resources, College of Sciences, Massey University, PO Box 11 222, Palmerston North, New Zealand 3. Institut für Geowissenschaften, Universit?t Tübingen, Sigwartstr. 10, 72076, Tübingen, Germany 4. Space Research Group, Department of Geophysics, E?tv?s University, Pázmány P. sétány 1/b, 1117, Budapest, Hungary 5. Netherlands Research Centre for Integrated Solid Earth Science (ISES), de Boelelaan 1085, HV 1081, Amsterdam, The Netherlands 6. Institute of Nuclear Research, Hungarian Academy of Sciences, Bem József tér 18/c, 4001, Debrecen, Hungary |
| Abstract: | A new model for the formation and relief evolution of the Danube Bend, northern Hungary, is discussed on geomorphological and volcanological grounds. We propose that the present-day U-shaped loop of the Danube Bend was partly inherited from the horseshoe caldera morphology of Keserűs Hill volcano, a mid-Miocene (ca 15 Ma) lava dome complex with an eroded central depression open to the north. According to combined palaeogeographical data and erosion rate calculations, the drainage pattern in the Danube Bend region was formed when Pleistocene tectonic movements resulted in river incision and sedimentary cover removal. Formation of the present curvature of the river was due to the exhumation of the horseshoe-shaped caldera as well as the surrounding resistant volcaniclastic successions (i.e. Visegrád Castle Hill) and a hilltop lava dome (Szent Mihály Hill). The process accelerated and the present narrow gorge of the Danube Bend was formed by very rapid, as young as late Quaternary differential tectonic uplift, also enhancing the original volcanic morphology. On the basis of comparative long-term erosion-rate calculations, we estimated successive elevation changes of the volcanic edifice, including partial burial in late Miocene time. In comparison with various order-of-magnitude changes, the mid-to-late Quaternary vertical movements show increased rates and/or base level drop in the Pannonian Basin. |
| Keywords: | Miocene volcanism Horseshoe-shaped caldera Differential uplift River incision Pannonian basin |
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