Wyniki badań miocenu solonośnego na południe od Przemyśla

Abstract

RESULTS OF STUDY ON THE SALT-BEARING MIOCENE DEPOSITS SOUTH OF PRZEMYŚL

Summary

Surface deposits of the Peri-Carpatian salt-bearing formation, referred to the earlier Miocene, have since a long time been known to occur within an area situated along the Carpathian margin, south of Przemyśl. Research works carried out by the Geological Institute from 1966 to 1968 allowed the line of the margin of the Carpathian overthrust and the width of the outcrop of the Peri-Carpathian salt-bearing formation to be determined in detail. Drillings have yielded here data to explain the lithological development of the deep-sealed salt-bearing deposits and of the younger deposits, i.e. the Stebnik Beds and the Balicha Beds. The salt-bearing formation lacks any rock salt seams here. There are found only salt clays, which prove a low degree of the intensity of chemical sedimentation. The examined lithological sections of the higher part of the Stebnik Beds did not confirm their salt content. These deposits reveal only gypsum intercalations or anhydrite concretions. Similar conditions, as concerns the salinity of waters in the basin, were characteristic of the later deposited Balicha Beds too. The Balicha Beds differ from the Stebnik Beds in having a considerably lower content of detrital materials; vanishing predominant brown and pink colours; and a predominance of clay materials green-grey in colour. The deposits of the Peri-Carpatian salt-bearing formation are deprived of microfauna. The microfauna of the Stebnik Beds is considerably poorer than that of the Balicha Beds. The results of research from the drilling made by the Geological Institute have proved the presence of the reversed stratigraphical sequence of beds, resulting from the overthrusting movements of the Carpathian margin (Fig. 2). The deposits of the salt-bearing formation, found to occur south of Przemyśl, most probably make the marginal part of the chloride facies field that widens along the margin of the Carpathians south-eastwards, as far as the West Ukraine area.