Glacifluviálně-glacilakustrinní sekvence u Vidnavy na severním okraji Žulovské pahorkatiny
| Title in English | Glaciofluvio-glaciolacustrine deposits near Vidnava at the northern margin of the Žulová Hilly Land |
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| Authors | |
| Year of publication | 2020 |
| Type | Article in Periodical |
| Magazine / Source | Geologické výzkumy na Moravě a ve Slezsku |
| MU Faculty or unit | |
| Citation | |
| Web | https://journals.muni.cz/gvms/article/view/13660/11708 |
| Doi | http://dx.doi.org/10.5817/GVMS2020-13660 |
| Keywords | Quaternary; Eastern Sudetes; Elsterian ice-sheet; outwash plain; glaciofluvio–glaciolacustrine environment; grain size |
| Description | Glaciofluvial and glaciolacustrine sediments were discovered in a small sandpit situated 800m SE from Vindava (the Polský kopec Site). Sediments fill two channels located in su-perposition. Three facies associations (FA) were distinguished in this sedimentary section. The base of the lower channel is formed by gravel lag overlain by gravel-sandy sediments of 3-D dunes and a side bar (FA1). The upper channel infill begins also by basal lag and grades to a fining-upwards sequence from sand to silt (FA2). The sequence is formed from the base up by sediments of small 3-D dunes, A-type ripples, B-type ripples, C-type ripples, and horizontally laminated sediments. The sequence reveals a vertical transition from glaciofluvial (sand) to glaciolacustrine (silt) sedimentation. The sedimentary section is terminated by flat glaciofluvial bedforms (FA3) deposited under upper plane bed condi-tions. These bedforms arose after the restoration of glaciofluvial conditions. The base of the glaciolacustrine sequence is located at an altitude of ~ 275m as well as the Old Kaolin Mine Site (850m SW from the Polský kopec Site) where very similar sediments have been already described. The sediments of both localities represent a proglacial outwash plain in front of the retreating ice sheet (FA1 consists of ~ 23% of erratic rocks), where a relatively large lake, or a system of smaller lakes evolved at the same time. |
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