Slate deposits of Moravia and Silesia [Czech Republic]

The slates of Moravia lie in the eastern part of the Czech republic, between Olomouc and Opava or Olomouc, Sternberk and Bruntal. The slates show a light grey colour with a partly occurring slight bluish shimmer and a rustic surface. Only small roofing slate slabs with a great thickness could be produced.

The area belongs to the eastern branch of the Middle European Variscan which is named 'Moravosilesian Zone' and builds the south-eastern edge of the Bohemian Massif (Walther, 1995). In the south-eastern part of the 'Moravosilesian Zone' the Moravian Kulm comprises the low mountains Drahansky Vrchovina and Nízký Jeseník.
According to the Geological map, the Moravian Kulm consist of Upper-Devonian and Lower-Carboniferous flysch series, comprising slates, sandstones and conglomerate bearing greywackes in which Tertiary volcanic rocks occasionally occur. The thickness of this series ranges between 18,700 ft. and 24,278 ft. and is devised in the Andelská Hora- , Benešov - , Moravice as well as Hradec-Kyjovice Formation (Dvorak, 1975). Except for the Benešovske Formation, the Moravian roofing slates are related to the Moravian Kulm.

The lithofacies and sedimentary structures of the Moravice Formation are very complex. They show deposits of high- and low density turbidites and possibly debris flows within the remnants of foreland basins (Mikulaš et al., 2002).

The tectonic setting is characterized by a NNE-SSW striking and relative simple moderate dipping fold style showing a west-vergency in the eastern part and an east-vergency in the eastern part. The intensity and age of folding and the metamorphism decrease from west to east: in the western part the Upper-Devonian units are deformed at the end of the Upper-Devonian whereas it was deformed probably at Namurian A/B in the east (Walter, 1995).

Abandoned slate quarries in Moravia

The fanning fracture cleavage is medium steep to steep (Kumpera, 1966) and seems to be only locally developed within the more muddy-siltic members. Within the more sandy coarse grained part the cleavage is only weakly developed and thus the bedding creates the main splitting plane.

Slate Types

Three different slate types can be distinguished in the Moravian district:

Regarding the active mining, the situation can quickly change. In 2016, the author was told that there exist plans to re-open a slate mine but it seems that all mines and quarries are still inactive.

Pictures

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  Fig. 1 Slate roof in Bruntal

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  Fig. 2 Slate roof in Bruntal (detail of Fig. 1)

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  Fig. 3 Slate roof with the typical rustic slate in Hermanice

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  Fig. 4 Slate roof with the typical rustic slate in Hermanice (detail of Fig. 3)

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  Fig. 5 The mostly still good slate shingles are going to leave the roof. Unfortunately, a lot of houses are under this conditions. Lacking money and awareness as well as the non-existence of slate roofers (Rudna pod Pradědem).

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  Fig. 6 With the expulsion of the Germans after World War II also the craftsmanship in slate vanished (Rudna pod Pradedem, detail of Fig. 5)

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  Fig. 7 Very beautiful thick Moravian slate.

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  Fig. 8 Moravian idyl in Old German style (Dolní Moravice)

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  Fig. 9 Dolní Moravice (detail of Fig. 8)

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  Fig. 10 Flooded quarry "Sv. Hermanice" (2016). The steep dipping cleavage plane builds the walls.