Výsledky geologického průzkumu kladenského souvrství severně od Nýřan v letech 2007–2021

Abstract

Coal-bearing sediments of the Radnice and Nýřany members (Kladno Formation) were explored in the SW part of the Plzeň Basin in an area between the villages Pankrác and Rochlov during field seasons of 2007–2021. The goal of the research was to find sites where the Whetstone Horizon (Radnice Member) and the Main Nýřany Coal Seam with fauna-bearing sapropel coal occur close to the surface. Both horizons bear record of the Fossil- Lagerstätte-type, which makes such areas promising for their future exploration as paleontological localities. Based on the combined information from old mining maps, boreholes and geological maps, we suggested sites suitable for future shallow excavations and paleontological research of the fossil-bearing horizons. We tested and further refined our assumptions based on evaluation of archival data from 51 shallow pits and 3 shallow boreholes. The Whetstone Horizon has been found in six different sites at depths between 2 and 7 m. Besides the typical architecture of the Whetstone Horizon composed of the coarse-grained light-coloured tuff at the base (so-called “bělka”) and overlain by laminated tuffitic mudstone (so-called Whetstone) tuffite – tuff – coal seam, also tuffite – tuff – mudstone, tuff – mudstone, tuffite – coal seam and tuffite – arkosic sandstone sequences have been documented. The pits demonstrated that the Whetstone Horizon features variable thicknesses over a short distance. Flora and fauna found in the bělka tuff bed is documented. The Main Nýřany Coal Seam with bands of sapropel coal has been found in two pits.