YEAR: 1987.

TITLE: Geology of the Paleozoic rocks in the vicinity of the Mokra Cement Factory quarries (Moravian Karst).

LANGUAGE: English.

JOURNAL / MONOGRAPH: Sbornik geologickych ved, Geologie, Vol. 42, pp. 41-88. Prague.

To manifest differences among small tectonic blocks in the Paleozoic of Moravia, to summarize maps and sections of Mokra quarries from last two decades.

Facies, carbonates, siliciclastic sediments, buildups, lenticular limestones, detritic carbonate banks, shales, sandstones, Culm, synsedimentary tectonics, block tectonics, tectonic segmentation, tectonics, quarried stone, sections, maps, stratigraphy, stratigraphical columns of wells, stratigraphical charts, list of fauna, sedimentology, Bohemian Massif, Moravia, Moravian Karst, Paleozoic, Devonian, Carboniferous, Givetian, Frasnian, Famennian, Tournaisian, Visean, facies correlation.

Geological Survey.

The area of Mokra in the south tectonic closure of the Moravian Karst consists of several tectonic segments. Each of these segments shows considerably different stratigraphy. The Early Frasnian sediments show only slight differences, but the sediments from late Frasnian to late Visean are specific for each of the tectonic blocks. Six blocks (A to F) have been described by means of lithology and biostratigraphy. Block A consists mostly of gray lenticular and nodular limestone of Famennian Pa. marginifera Zone, the underlying reef banks are Frasnian. There are numerous neptunian dykes, which represents variegated Famennian fills in Frasnian limestone. The overlying sediments are unknown as they were eroded or cut by a fault. Block B has only relicts of this Pa. marginifera nodular limestone but the massive grainstones with Megalodon shells, which were sampled at Crusher, yielded the conodonts of the same age - Pa. marginifera. This is just the place, where J. Dvorak continued the Vilemovice Limestone up to Pa. marginifera Zone. If Vilemovice limestones are simplified only to meaning of the light and massive banks, then it is fairly correct. A large hiatus (lacuna) is above and the next onset of the Famennian-Tournaisian organo-detritic and nodular banks was dated to Bi. costatus Zone. Another big lacuna is above the Tournaisian limestone beds. Visean shales and siltstones covered the eroded surface of limestones. Block C is characteristic by thinning upward of Vilemovice limestone. Onset of clayey lenticular limestone is dated in Pa. crepida Zone. Detritic banks of late Famennian and middle Tournaisian age locally thicken condensed sequence. The middle Tournaisian phosphorite-bearing breccias are several meters thick. In spite of many lacunae, the carbonate banks and red shales have also Tournaisian-Visean ages. It is possible, that late Visean siltstone and conglomerate formations continued this stack of sequences in a sense of sedimentary, not tectonic continuation. Block D (on the northeast of the quarries) is fairly similar, with an exception for direct cover of the Vilemovice (Mokra) limestone. This cover consists of dark gray detritic banks, in contrast with lenticular limestones of the blocks C and E. Block E corresponds to well-known sequences of the Western Quarry of Mokra. Tectonic styles of the blocks C and D suggest a tectonic deformation even before the erosion base of the late Visean conglomerates. Frictions among the individual authors can be exemplified by Fig. 19. An interfingering of disintegrated "pebbly" limestone beds and shales to siltstones is involved in this diagram. J. Dvorak explained this structure as a document for concurrent sedimentations of limestones and shales, but J. Hladil and J. Kalvoda believed that this structure is a folded and sliced contact between the Tournaisian-Visean limestones and Visean siltstones and shales. All right, the authors of this contribution agreed the fact that Mokra area consists of fairly different small blocks. These blocks are not larger than 600-800 m by width of 100-300 m. However, the differences in stratigraphy, which are of primary importance, were explained in different ways. J. Dvorak as a chief author suggested that 80% of these features must be explained by varied vertical movements of the blocks, which were mostly in compression. In this concept, majority of the faults is very old and most of them synsedimentary. J. Hladil and J. Kalvoda suggested that this structure originated from Variscan tectonic slices or nappes being significantly changed by vertical faults during Permian, Mesozoic and Tertiary.