Wiercenie Rzeszotary2

Abstract

BORE-HOLE RZESZOTARY 2

In 1909, W. Petraschek described the bore-hole drilled at Rzeszotary, SE of Cracow and W of Wieliczka. According to this author, this drilling perforated successively the Flysch Cretaceous, the Palaeogene Tertiary, the Jurassic and the Carboniferous, and then penetrated the crystalline substratum at the depth of 849 m.

W. Petraschek’s interpretation was questioned not only as regards-the sedimentary-rocks pierced, but also as to the crystalline substratum having been encountered in situ. This the more so, since the author himself had doubts regarding his interpretation. In view of this controversy regarding the interpretation of the Rzeszotary 1 bore-hole, Professor M. Książkiewicz suggested drilling, in the vicinity of the first, a new well - Rzeszotary 2.

This new bore-hole, location variegated Godula shales, pierced the flysch rseies; then it entered, as far as the depth of 170 m., successively older strata of the Silesian Lower Cretaceous (dark argillaceous shales, marly shales with calcareous sandstones). They belong to the Wierzowice, Grodziszcze and the upper Cieszyn beds. At the depth of 170-176,6m. there appeared Eocene glauconitie sandstones and Upper Cretaceous variegated marls (Węglówka beds) of the Subsilesian unit, reduced here to a thickness of barely several meters. From 176,6 m. to 750 m. Miocene sediments (of the Lower Tortonian) were perforated. These are alternatebedded marls, silty sands, sandstones and conglomerates with fauna. Underneath the Miocene as far as depth 845,7 m, lie sediments of the fore-land; they consist of Upper Jurassic (Rauracian) rocky limestones with flints. Furthermore, crinoid limestones (Neuvizyan) were perforated, sandy in their bottom part and containing small conglomerate fragments.

Drilling operations were interrupted at the depth of 965,0 m. in the crystalline substratum. Thus only 119,3 m. were drilled in this substratum, in situ. On the basis of megascopic observations, the crystalline substratum may be described as a series of diaphioretically altered amphibolites and injection gneisses, showing features of granitization.