Fossil karst in the jurassic of the koœciuszko mound in kraków (southern poland)

Abstract

Study of four boreholes (each 100 m deep) drilled in St. Bronislawa Hill (part of the horst of the Wolski Forest, Kraków) indicates that the Oxfordian lime stone is interbedded by clay stones with calcareous rubble (detritus) filling fossil karst forms. The clay stones, locally showing planar stratification, contain assemblages of Late Cretaceous (Campanian–Maastrichtian) foraminifers. Middle Miocene planar laminated lime stones have also been found in cavities formed in the Middle Oxfordian limestones. Miocene deposits of this type, filling the fossil karst, were not previously known from the area of Kraków. Both the Upper Cretaceous and Middle Miocene deposits document probably marine sedimentation that resulted in the filling of the karst system. This type of karst was probably formed before the transgression of the Late Cretaceous sea, and before the transgression of the Middle Miocene sea on the area of the present-day horst of the Wolski Forest.