KALCIT-BARYTOVÉ KONKRECE Z TĚŠAN, OKR. BRNO-VENKOV: NÁLEZ, DATA A MOŽNÉ DŮSLEDKY

Unique calcite-barite concretions from Těšany (district Brno-country) have been found and studied in detail. These concretions and large limestone boulders are considered to represent material from the Jurassic period and present the only material and opportunity to improve knowledge about these unussual rocks in the studied area. EPMA has been used to constrain complex mineralogy. Results in this study are supplemented by LA-ICP-MS microanalysis. The increased precision is related to combination of different methods (PL, CL and BSE imaging) to distinguish compositionaly different calcites as a separate groups investigated by scans of multi-point analyses. Based on microtextural observations and chemical analyses 3 calcite groups are distinguish. This study provides new information for widespread sulphates (5–20 %) and fi ne-grained quartz (5–35 %) too