Związek kwarcytów okolic Bolesławca z tektoniką trzeciorzędową i perspektywy poszukiwawcze

Abstract

RELATION OF QUARTZITES FROM THE VICINITY OF BOLESŁAWIEC TO TERTIARY TECTONICS AND PROSPECTING POSSIBILITIES Summary In the Lower Silesian area, west of Bolesławiec, in the vicinity of Kliczków and Osiecznica, there are exploited deposits of siliceous sandstones, usually called quartzites. Silicification affected here the feebly diagenetic Upper Cretaceous sandstones and Middle Miocene sands with brown coal seams. In the literature the silicification has been related to the diagenetic processes. The authors have ascertained here the occurrence of silica and opal and chalcedony crusts, also on the plant stalks (a type of sinters), mountain crystal, veins of cement quartzites, strongly silickensided quartzites (siliceous stylolites), as well as siliceous sandstones in the form of banks and concretions. Thus we may draw a conclusion here that the quartzite deposits situated along a WNW-ESE line must have been formed due to silicification with silica from thermal water. This process is only slightly younger than that concerning the sedimentation of Middle Miocene age. The silicification accompanies the surface of both longitudinal and transversal faults and of similarly oriented fractures. Most of them are thought Ito be of shear plane nature. The strongest silicification may he observed at the crossings of the surfaces of discontinuity mentioned above.