Acta Musei Moraviae

Chemistry of rocks of the Macocha and Líšeň Formations in the Mokrá Quarry (Moravian Karst)

The quality of cement clinker is related to the chemistry of the raw materials (typically limestone and clay or shale and other materials) used. The paper provides detailed information about chemistry of rocks of the Macocha and Líšeň Formations quarried as raw materials for cement production in Mokrá in the southern part of the Moravian Karst (north of the town of Brno). The Vilémovice Limestones is the only lithostratigraphic member of the Macocha Formation in the Mokrá Quarry. Massive Vilémovice limestones are very pure with only 1.5 wt. % SiO₂ and 0.4 wt. % Al₂O₃ on average. A nodular variety of Vilémovice limestones has increased contents of SiO₂ (3.3 wt. % on average), Al₂O₃ (1.5 wt. %) and also alkalies, represented mainly potassium (0.3 wt. % K₂O). Rocks of the Líšeň Formation are composed of a carbonate component (calcite) and a non-carbonate component (dominantly quartz and muscovite / illite), whose quantitative ratio is highly variable Limestone of the Líšeň Formation (sometimes very pure) pass into calcareous shale due to increase in non-carbonate component and then into silty shale containing only a few percent of calcite. This corresponds to the wide variability of CaO, SiO₂, Al₂O₃ and alkalies (K > Na). The K₂O content in shales of the lithostratigraphic member Hády-Říčka Limestones is in the range of 2.3 to 4.4 wt. % (3.3 wt. K₂O on average). In the article are presented and discussed the contents of a series of minor and trace elements (P, Ti, S, Fe, Mn, Sr, Rb, Zr, As, Cu, Zn, Pb and REE).