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The 2140 01T1 borehole sampling the Late Cretaceous non-marine strata of the Klikov Formation in the central part of the Třeboň Basin in southern Bohemia provided ~ 70 m thick alluvial succession composed of alternating sandstone and mudstone intervals that overlays deeply weathered crystalline basement. The mudstone interval in the lower part of the Klikov Formation is separated by sandy layers into several 2-4 m thick fining-upward units. The sharp-based sandy layers with fusain, carbonized stems and rip-up clasts of underlying mudstone are interpreted as avulsion deposits. They grade upwards into heterolithic sand-silt sequence and mottled massive mudstone with burrows, rhizohalos and variably developed pedogenic features. Such cyclic arrangement probably reflects autogenic processes on distal floodplain with episodic deposition and upward increasing subaerial exposition and pedogenic overprint. In the middle to upper parts of the Klikov Formation up to 6 m thick channel sandbodies with sharp erosional bases cutting into the underlying laminated sand-silt heteroliths of channel levee deposits occur. The thickness of the single-storey sandbodies corresponds usually to c. 2 m which suggests up to 3 m deep channels during bankfull discharge. The thicker multi-storey sandbodies record channel amalgamation on the alluvial ridge or shallow paleovalley fillings. The sandbodies grade upwards to massive mudstones of abandoned channel fills and floodplain deposits. These floodplain units are up to 8 m thick and consist of variegated massive mudstones interrupted by discrete up to 1 m thick fining upward layers of rippled sandstone representing crevasse splay deposits. Depositional context including preserved levee deposits, abandoned channel fillings and floodplain finegrained deposits suggests rather higher sinuosity of the formative rivers. Palaeosol profiles represent pedogenically modified floodplain fines with gradational bases and sharp erosive top surfaces. At least 10 palaeosols were identified in the measured section, forming mostly discrete profiles up to 2 m thick consisting of several B-horizons that differ in the degree of the soil structure development, colour, mottling, grain size, presence of clay hypocoatings and bioturbation index. The most common Bw horizons form lower parts of the profiles and have no or only a weakly developed angular blocky structure (ABS). The typical mottling is caused by a hierarchical system of vermicular greenish-grey reduction rhizohalos, that may be filled by silt to sand or illuviated clay hypocoatings and probably follow the original plant root system. Some patches have diffuse orange rims of iron oxides, probably represented by goethite. Mudstone of Bsst horizons displays well-developed ABS with rare wedge-shaped peds and contains a number of illuviated clay skins and redox depletions. Vertic features like fine cracks filled by sand are common, and slickensides with clay hypocoatings occur rarely. Mudstones of Bt horizons contain a number of illuviated clay hypocoatings filling root channels or interpedal cracks, while the Bss horizons exhibit well-developed ABS with slickensides and contain a number of vertical cracks filled by sandy grains. Palaeosol profiles represent mainly argillisols and vertic argillisols with transitions to argillic vertisols. Poorly developed argillic to vertic protosols are also common. Palaeosol profiles differ mainly in the degree of structural development/maturity, which is given by various lengths of exposition to similar climatic conditions. Vertical distribution of palaeosols reflects their position in the alluvial landscape with locally specific hydromorphic conditions rather than a distinct climatic trend. Most of palaeosols exhibits downprofile translocation of clay (illuviation) leading to the formation of argillic horizon, which typically develop on stabilized landscape in humid climate with seasonal moisture deficit. Seasonal water table fluctuations are also evident from the presence of vertic and redoximorphic features. Rather low evapotranspiration during arid periods indicated by the absence of calcium carbonate accumulation and weakly developed vertic features may most probably reflect short-lived arid seasons. [ABSTRACT FROM AUTHOR]

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-Lagerstatte-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. [ABSTRACT FROM AUTHOR]