View of the thrust structures development in the easternmost part of Ostrava Karviná Coalfield

WACLAWIK, Petr, Andrea BERČÁKOVÁ, Michal OSOVSKÝ a Jiří PTÁČEK. View of the thrust structures development in the easternmost part of Ostrava Karviná Coalfield. 17th Meeting of the Central European Tectonic Group (CETEG) 2019: Rozdrojovice, 27-27 April, 2019 : abstract volume. Prague: Czech Geological Survey, 2019, s. 91-93, 103 s.

Základní údaje

• Originální název: View of the thrust structures development in the easternmost part of Ostrava Karviná Coalfield
• Autoři: WACLAWIK, Petr, Andrea BERČÁKOVÁ, Michal OSOVSKÝ a Jiří PTÁČEK.
• Vydání: 17th Meeting of the Central European Tectonic Group (CETEG) 2019: Rozdrojovice, 27-27 April, 2019 : abstract volume, Prague, Czech Geological Survey, 2019.

Další údaje

• Originální jazyk: angličtina
• Typ výsledku: Článek v odborném periodiku
• Stát vydavatele: Česká republika
• Utajení: není předmětem státního či obchodního tajemství
• Organizační jednotka: Přírodovědecká fakulta
• Klíčová slova česky: Ostravsko-karvinský revír, centrální přesmyk, východní přesmyk
• Klíčová slova anglicky: Ostrava Karviná Coalfield, Central thrust, Eastern thrust

Anotace

Ostrava Karviná Coalfield presents the Czech part of Upper Silesian Coal basin, which is the part of East-European Variscan orogeny. Due to the rich variety of the geological properties, it produces many themes for the studies of the geological structures. From this point of view, it is important that the coal basin is exploited yet. It is evident the division of the Czech part of USCB into western part with the high degree of folding and eastern part with subhorizontal bedding. Similarly, we can observe the decrease of the deformation intensity eastward. But even in the easternmost part of Upper Silesian block, which is characterized by normal faults and brittle tectonics, the compressional structures and flat folds are presented. As the structural pattern is important for the mining design and planning, the high attention is paid to it since start of mining. The structural pattern is known in general now, nevertheless many times we find out during mining development a new unexpected geological information, which we must solve operatively. The prediction of the faults course is not working. Similar, it was working in the case of thrusts systems in Upper Silesian block. Two systems of thrust structures was determined there, Central thrust, examined in Doubrava mine and Eastern thrust, described in detail in mines Darkov, ČSM and 9.květen. The both systems are considered originally make up a whole, but following exploration during mining development shoved, that they are two independent systems. Space orientation of thrust structures proves univocally that they are older than main normal faults system, which are corresponded with Variscan directions, approximately NNE–SSW and WNW–ESE. The direction of Central thrust changes from the West to the East. Originally N–S direction rotate to W–E direction. Eastern thrust respects the direction similarly NE–SW, but it changes locally too. The nature of Eastern thrust approximates to the thrust structures in apical zone of orogenic front. It consists of the flat thrusts combined with the interlayer slip. But the faults of Central thrust system described in Doubrava mine are mostly of the same character. The change of motion amplitude is the important feature for the both thrust systems. While the amplitude of the Central thrust decrease to the East, the amplitude of the Eastern thrust decrease to the SW. That fact was the main argument for dividing overthrusts into two separately systems. But for decisive factor, we consider the change of maximal horizontal stresses, measured in the regions of both thrust systems, In the region of Central thrust prevails N–S direction, while in the region of Eastern thrust system NW–SE direction. The different mobility of constituent elements of Variscan rock mass is considered for decisive source of it. It develops, due to locally increasing of press, to breaking up the originally consistent rock mass into the individual blocks. The block mobility differentiation caused the dextral strike slip, which is clearly documented in the Western and central part of OKC. Horizontal moving component is often more than 100 meters. The traces of the Central thrust in the seam No. 24 are shifted eastward in the North block compared to South block. This is, after all, the evidence of the relative age of the overthrusts and normal fault systems. The overthrust systems originated probably in the early phase of Variscan orogenic processes and they were gradually deformed by following movement including the dextral rotation of the blocks.