Alkálie v břidlicích rozstáňského souvrství těžených ve velkolomu Mokrá (Moravský kras)
| Title in English | Alkali elements in shales of the Rozstání Formation extracted from the Mokrá Quarry (Moravian Karst) |
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| Authors | |
| Year of publication | 2014 |
| Type | Article in Periodical |
| Magazine / Source | Geologické výzkumy na Moravě a ve Slezsku |
| MU Faculty or unit | |
| Citation | |
| Field | Geology and mineralogy |
| Keywords | Moravian Karst; Rozstání Formation; alkali elements; shales; Mokrá Quarry |
| Description | Limestones of the Macocha and Líšeň Formations and silty to clayey shales of the Rozstání Formation as cement raw material are extracted from the Mokrá Quarry in the southern part of the Moravian Karst. Limestones of the both mentioned formations have only very low concentrations of potassium and sodium. The paper is focused on the study of chemical and mineralogical composition of the mentioned shales sampled in the eastern part of the Mokrá Quarry. The rocks have been investigated by using EDX analysis. In the studied shales, a pelitic fraction usually prevails over an aleuritic one. Up to 90% of the pelitic fraction comprises phyllosilicates (mainly muscovite and illite), hereinafter identified quartz and feldspars (K-feldspar, less often plagioclase). Aleuritic component is significantly represented by quartz. The studied rocks are rich in alkali elements (2.5 wt. % K2O and 2.6 wt. % Na2O in average). Potassium occurs in phyllosilicates of the composition corresponding to illite (or) muscovite and to biotite, partly replaced by chlorite of the clinochlore-chamosite series. Sodium is present in feldspars. It is clear that silty to clayey shales of the Rozstání Formation may significantly affect the total alkali content in the produced cement. Data are tabled and discussed. |