Litologia osadów siarczanowych miocenu w rejonie staszowskim

Abstract

Przedstawiono wyniki badań litologicznych osadów siarczanowych miocenu na obszarze między Chmielnikiem a Staszowem. Dały one podstawę dla wyróżnienia dwudziestu odmian litologicznych skał gipsowych i towarzyszących im utworów pogipsowych. Tworzą one w obrębie kompleksu gipsowego sekwencję szesnastu (oznaczonych ad a do o), scharakteryzowanych dokładniej litotypów.

LITHOLOGY OF THE MIOCENE SULFATE DEPOSITS IN THE STASZOW REGION

Based on lithologic testing sixteen lithotypes (marked a to o in Fig. 2) have been distinguished in the sulfate deposits in the exploratory boreholes carried out by State Geologic Institute in the Staszów region (between Chmielnik and Staszów - Fig. 1). The lithotypes are represented by various lithologic types of gypsum rocks interbedded with clayay rocks and claysilty rocks. Gypsum rocks are characterised by a richness of structures and various chemical compositions (Tabs. 2. 3). Average mass fractions of CaSO₄ • 2H₂O, CaCO₃ and HCl-insoluble parts in rocks tested have been determined on the base of chemical analyses as 83,87%, 3,58% and 6,47% respectively.

Basic lithological types are represented by the following gypsum rocks: selenitic rocks. selenic-micritic rocks, micritic rocks and gypsum breccia, including a series of other lithologic types of gypsum rocks (Tab. I).

A sequence of sulfate deposits in the Stasz6w region begins with glassy selenitic gypsum rocks (lithotype a, Fig. 2). They are covered. with a complex of micritic beds and selenitic gypsum rocks inter-bedded with stromatolite gypsum rocks (lithotypes: b-e; Tabl. I. Figs. 4, 5; Tabl. II, Figs. 6, 7). Above in the profile occur skeletal selenitic gypsum rocks (lithotype f) composed of selenites some centimeters in size interbedded and intergrown chaotically (Tabl. II, Fig. 8; Tabl. Ill, Fig. 9). Towards the top the rocks alternate gradually into sabre-like selenitic gypsum rocks (lithotypes g, i), consisting of highly elongated (of 20 cm or more), unidirectionally curved selenites (Tabl. III, Fig. 10; Tabl. IV, Fig. 13), inter-bedded with mictitic gypsum rocks laminated undulatedly (the tickest interbed makes up lithotype h; Tabl. Ill, Figs. 11, 12). Micritic gypsum rocks (lithotypes j and I; Tab!. IV, Figs. 14, 15) interbedded with clayay, silty-clayay rocks, gypsum breccia, or highly clayed gypsum rocks (lithotypes k. ł; Tabl. IV, Fig. 16) occur higher in the profile. The upper part of the gypsum sequence in the Staszów region comprises micritic and sclenitic-micritic gypsum rocks with gypsum breccia beds (lithotypes m-o: Tabl. V, Figs 17-20; Tabl. VI, Fig. 21). Above the complex of gypsum rocks past gypsum formations - represented by porous limestones, breccia limestones, limestones coarse liminated with clay and marls (Tabl. VI, Figs 22-24) are found in several boreholes. Texture and structure of the primary gypsum rocks. are maintained. Lithotypes distinguished (from a to o) have their lithologic homologues in the profile of gypsum rocks in the Nida region (A. Wala. 1979).