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Fossil thermokarst in South Bohemia (Czech Republic)

Publication at Faculty of Science, Central Library of Charles University |
2018

Abstract

The presented paper deals with the Late Pleistocene geomorphological and sedimentological evolution of the Třeboň region in South Bohemia. Relict periglacial features like fossil thermal-contraction-crack-polygons documented in the study area prove the presence of permafrost in the region during the Late Pleistocene.

Moreover, besides these periglacial features, we have discovered a total of 27 depressions filled with lacustrine sediments and peat. Most of them are covered by artificial fishponds of Medieval and Modern origin and thus hardly recognized in the landscape.

According to radiocarbon and relative palynological dating, the largest basins were formed along the Pleniglacial/Late Glacial transition (~ 16-15 ka), whereas the smaller depressions originated during the Late Glacial/Early Holocene.we assume that these basins are the result of the complex of thermokarst processes, including formation and collapse of alases and consequent surface degradation of the permafrost, which occurred here during periglacial conditions of the Late Weichselian.