Thermal basal regime of the Elsterian ice-sheet marginal zone in a hilly mountain foreland, Rychleby Mts., Eastern Sudetes
| Autoři | |
|---|---|
| Rok publikování | 2021 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | Boreas |
| Fakulta / Pracoviště MU | |
| Citace | |
| www | https://doi.org/10.1111/bor.12505 |
| Doi | http://dx.doi.org/10.1111/bor.12505 |
| Klíčová slova | ice sheets; sedimentology; Rychleby Mountains foreland |
| Popis | The Scandinavian Ice Sheet reached the Sudetes and Carpathian Mountains during the Elsterian glaciation. A long ice-sheet piedmont marginal zone affected by the rugged mountain foreland topography and associated slopes originated. This study focuses on the hilly Rychleby Mts. foreland (Eastern Sudetes, Czechia), which was a part of the piedmont marginal foreland zone of the ice sheet. The basal regime was reconstructed through an investigation of the sedimentology, structural features, and the nature of ice-sheet erosion of preglacial landscapes evident at two sites located similar to 3-5 km inside the maximum ice-sheet extent. These sites show a preglacial relief buried by sub- to supraglacial sediments. The sites were located under an ice cover of max. 200 m. Evidence of cold-based conditions (including palaeotors with delicate structures on the bedrock, almost absent striations on clasts, originally frozen unlithified sedimentary rafts) exists at both sites. Permafrost composed of coarse-grained sediments was subject to brittle deformation at the base of the ice sheet, whereas permafrost composed of fine-grained sediments underwent ductile deformation. The margin of the Scandinavian Ice Sheet in the Rychleby Mts. foreland was cold-based, therefore glacial erosion was not sufficient to significantly remodel the palaeotors into roches moutonnees. During ice-sheet decay, the preglacial landscape was partially buried by melt-out tills and meltwater sediments. |
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