Stratygrafia utworów karbonu północno-wschodniej części Lubelskiego Zagłębia Węglowego

Abstract

Na podstawie makrofauny z 13 otworów wiertniczych określono stratygrafię karbonu północno-wschodniej części Lubelskiego Zagłębia Węglowego. Fauna dokumentuje wizen górny, namur dolny i górny westfal A i B. W kilku otworach w obrębie namuru stwierdzono luki stratygraficzne.

STRATIGRAPHY OF THE CARBONIFEROUS OF NORTH-EASTERN PART OF THE LUBLIN COAL BASIN

Carboniferous sections are thinner in north-eastern part of the LubIin Coal Basin (Radzyń and Parczew region) than in the remaining parts, ranging from 618 m (Wygnanów IG 1) to 185.0 m (Radzyń IG 6) in thickness. The differences in thickness result from gradual wedging out of the deposits to the north-west, differences in advancement of erosion of the Westphalian and erosion from the the Namurian times (Fig. 1).

Marine, fresh-water and. brackish fossils derived from 13 boreholes evidence ,the Upper Visean, Lower and Upper Namurian and Westphalian A and B. The stage and substage boundaries were delineated on the basis of the fauna and some constant lithological indices. The boundary between the Lower and Upper Namurian is arbitrarily drawn in the majority of boreholes. This interval is characterized by very rare and poorly preserved representatives of guide species and, sometimes, complete lack of fossils.

Figures 1 and 2 show correlation of stratigraphic units and differentiated faunal zones (Posidonia corrugate I, P. corrugata II, Carbonicola pseudorobusta and Dunbarella zones) and Table 2 - shares of representatives of families and some species in fossiliferous intercalations from 7 boreholes selected. The full list of taxa recorded in these boreholes is given in Table 1.

The Upper Visean .is evidenced mainly by the representatives of the genus Gigantoproductus, bivalves (Pectinacea) and single goniatdtes.

The fauna recorded in the Lower Namurian indicates the presence of stratigraphic gaps. The sections of the Parczew IG 1 and Parczew IG 7 boreholes are the most complete. In other boreholes, the interval between the·Upper Namurian faunal assemblage and the E₂ or E₁ fauna varies in length.

The profiles of the Westphalian A are relatively uniform in thickness and their faunal records are good. The fossils important from the stratigraphic point of view include fresh-water bivalves of Ithegenera Carbonicola and Naiadites and innumerous goniatites, brachiapods and marine bivalves. The faunal assemblage is indicative of the zone with Lenisulcata, Communis and Modiolaris.

Marine fauna is not present in the Westphalian B and this stage is dated by fresh-water bivalves of the genera Anthracosia and Naiadites.