Vol 20, (1984)
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- Category: Vol 20, (1984)
Authors: Josef Pašek
Full version (12,608 kB)Abstract: Erosion phenomena are described from the Antonin Uxa mine (the former Krimich II mine) in the eastern part of the Plzeň Basin (SW Bohemia), occurring In the autochthonous Main Nýřany humite Coal seam (Westphalian D). Very soon after having been overlain by roof claystones, the coal hemitype constituting the main coal seam was eroded by a network of watercourses. These sediments represented the basal member of the subsequent cycle of sedimentation. They filled the erosion furrows with elastics which also formed the beds overlying the coal seam. These elastic rocks contain angular fragments of coal, which are just as coalified as the main coal seam Itself. At the same time plastic deformations of this coal seam occur due to the non-uniform distribution of elastics in this cycle. Determining the age of the coalification, the author concludes that coalification of the seams attained the stage of hard coal (bituminous banded coal) as early as before the erosion, the erosion interval having an unusually short time span corresponding to the deposition time of the cycle of the overlying sediments. The author's opinion, the erosions are controlled by the differential compression of the sediments thickly deposited in depressions and thinly above the elevations of the presedimentary relief, and to the fact that elevations ( and coal seams) became relatively accessible as it corresponds to the profile of the pre-Carboniferous relief of the studied area.
