Cross-bedding and erosion surfaces/reactivation surfaces in the sandstones of the Příhrazské skály Cliffs (Bohemian Paradise)
Abstract
The quartzose sandstone body forming the Příhrazské skály Cliffs in the Bohemian Paradise area was deposited in the NE part of the shallow-marine Bohemian Cretaceous Basin. The 90-100 m thick body is homogeneous in its lithology, with no intercalations of other lithotypes. Cross-bedding is the main sedimentary structure, forming sets several centimetres to 6 m thick. One set attains the thickness of 25-30 m. Variable orientations of the foreset laminae indicate an interaction of tidal currents, wind-driven currents, storm-induced currents and semipermanent currents. The cross-bedded units are comparable with ripples and sand dunes occurring in modern shelf seas and straits.