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The Racławka Valley – an example of an educational geosite related to the development of a Paleozoic carbonate platform

Szczurek S., Bąk M., Dulemba P.

Geotourism / Geoturystyka

2016

nr 1-2

45--56

The location and most interesting geological features of the Upper Devonian through Lower Carboniferous limestones in the Racławka Valley were presented. The limestones outcropped almost continuously along the natural valley cutting. They comprise over 60 million years of continuous growth of the carbonate platform, which developed on the ancient terrane – the Upper Silesian Block. Geosites described herein may constitute a destination for geological trips for undergraduate students of Environmental Sciences, where they can actively discover the development of an ancient carbonate platform and accompanied post depositional structures.

W dolinie Racławki znajdują się ważne geologicznie naturalne odsłonięcia wapieni (od późnego dewonu do wczesnego karbonu). Wapienie te obejmują okres ponad 60 milionów lat ciągłej sedymentacji węglanowej, która występowała na obszarze paleozoicznego kratonu – bloku górnośląskiego. Opisane stanowiska mogą być celem wycieczek geologicznych studentów pierwszego stopnia studiów przyrodniczych, w czasie których mogą oni w aktywny sposób śledzić rozwój kopalnej platformy węglanowej i struktur postdepozycyjnych.

Holocene tufa in the Slovak Karst : facies, sedimentary environments and depositional history

Gradziński M., Hercman H., Jaśkiewicz M., Szczurek S.

Geological Quarterly

2013

Vol. 57, No. 4

769–-788

Several tufa complexes are known in the Slovak Karst which is a typical karst area of a temperate climate. This area is built of Mesozoic carbonates, mainly Triassic in age. The karst systems drain carbonate plateaux and lead water to resurgences located in valleys which are up to 300 m deep. Below the resurgences there are Holocene fossil tufa deposits that exceed 12 m in thickness. The tufas include stromatolite, moss, phytoclastic, oncoidal, and intraclastic facies. Extensive barrages which once dammed the upper reaches of the streams were formed in narrow valleys. They are composed predominantly of moss facies and stromatolites, with subordinate oncoidal and phytoclastic facies. Phytoclastic, oncoidal and intraclastic facies are dominant in dammed segments of streams, and include gastropod shells and charcoal fragments. Some small moss cushions are also developed. Barrages and dammed areas formed in a longitudinal fluvial depositional system. Conversely, below resurgences located on plateau slopes tufas of a perched springline depositional system were formed. These comprise deposits of prograding cascades constructed by moss, phytoclastic and stromatolitic facies. Presently, the tufas analysed are inactive. They stopped growing in the Late Holocene time, after which there was abrupt incision of the streams. This caused downcutting into Holocene tufas, in some places reaching Mesozoic bedrock. At present tufa is being precipitated from streams in all the sites studied.