Osady paleozoiczne wiercenia Zalesie 1 koło Szczucina

Abstract

PALAEOZOIC DEPOSITS PIERCED BY THE BORE BOLE ZALESIE 1 NEAR SZCZUCIN

The following series of the Palaeozoic deposits has been pierced by the bore hole Zalesie 1, located near Szczucin in the southern area of Poland: Lower Carboniferous (1377,5-1734,0 m), Lower Devonian (1734,0-1832,0 m) and Ordovician (1832,0-1872,5 m).

The Lower Carboniferous deposits consist of limestones with claystone, dolomite and anhydrite intercalations, and in the lower part (1655,0-1734,0 m) of dolomites. At a depth from 1377,5 to 1409,0 m the fauna has been encountered of Middle Visean, or of the lowermost part of Upper Visean age. In the dolomite series the fauna of probable Tournaisian age has been found as well.

The Lower Devonian in the Old Red facies is built up of sandstones, mudstones and claystones, variegated at the top and grey-green at the bottom, with characteristic pseudoscolitus structures.

The upper part of the Ordovician developed in the form of clay shales contains graptolites showing the Lower Caradocian, higher than the zone Nemagraptus gracilis. The lower part of the Ordovician consists of the arenaceous-mudstone deposits with gIauconite and graptolites proving the transition time from Arenigian to Llanvirnian.

Some hiatuses may be observed in the Zalesie section: 1) between the Lowr Devonian and Caradocian - as a result of the Late Caledonian movements; and 2) between the Lower Carboniferous and Lower Devonian - due to the Bretonian movements. The electric logging correlation of the Lower Carboniferous deposits from the bore holes Zalesie 1, Mędrzechów 1, Bratkowice 1 shows that the Carboniferous from Mędrzechów and Bratkowice corresponds to the upper part of the Carboniferous from Zalesie. In this part of the Carpathian foreland, the Carboniferous transgression took place in two stages. During the first stage it embraced an area between Żółcza, Zalesie and Niwiska, and laid down dolomites and limestones, and then was temporarily stopped (sedimentation of anhydrites at Zalesie and Żółcza). In the second stage the sea embraced the whale area of the Carpathian foreland. In the area considered, the post-Hercynian denudation removed the young-Palaeozoic deposits so that only one stratigraphical horizon persisted, i.e. the lowermost part of the Upper Visean.