Przesłanki dla poszukiwań złóż dolnodewońskich piaskowców kwarcytowych w rejonie Iwanisk

Abstract

PREMISES FOR PROSPECTING OF LOWER DEVONIAN QUARTZITIC SANDSTONES IN THE IWANISKA AREA Summary The paper deals with preliminary results of prospecting and lithological and raw material studies of Lower Devonian sandstones from the area of lwaniska. On the basis of historical, geological and geophysical premises it can be assumed that in the area of lwaniska a number of quartzitic sandstone deposits occur in the vicinity of Poręba Górna, Podlesie and Kopiec. Favourable conditions for occurrence of the sandstone deposits exist in zones of transversal depressions, where the Lower Devonian attains greater thickness and where the belt of its outcrops is much broader. (Fig. 2). The scheme of lithological-facial development of the Lower Devonian, reconstructed by the author, is very useful in prospecting for raw material deposits. The profile of the Lower Devonian consists of two mottled series separated in the middle by a sandstone series. Locally, there also occur thin upper sandstone series. Quantitative lithological analysis showed that only the middle sandstone series of the Lower Devonian, which in the depression zones of Poręba Górna and Podlesie is up to 50 m thick, represents a deposit value. The occurrence at deposits of Lower Devonian sands tones in those regions is also confirmed by the results of electroresistance and geophysical logging surveys. Geophysical characteristics of the Lower Devonian in the area of lwaniska have been elaborated (Table I). It has been established that the middle sandstone series, interesting as a deposit, has contrast geophysical properties in relation to the adjoining mottled series. Correlation of electro-resistance curves with geological profiles is remarkable (Fig. 3). Usefulness of electro-resistance surveys was found both in prospecting and documentation of deposits of Lower Devonian quartzitic sandstones. Favourable physical and strength properties of the sandstones point to their wide applicability in general and engineering building, in road and railway track building, as well as in production of aggregates and semiproducts (Table III).