Mikrofacje wapieni a pozycja facjalna osadów górnego wizenu z północno-wschodniej części Lubelskiego Zagłębia Węglowego

Abstract

LIMESTONE MICROFACIES AND FACIES POSITION OF UPPER VISEAN SEDIMENTS IN NORTH-EASTERN PART OF THE LUBLIN COAL BASIN Summary Carboniferous sequence in the Lublin Coal Basin starts with the Limestone-Claystone Series, which in the marginal part of the Basin (Text -Fig. 1), between Włodawa in SE and Parczew in NW, is composed of marine units intercalated with continental deposits (Text - fig. 2). The marine units are represented mainly by limestones, among which distinguishable are 10 microfacies (Text - fig. 3): algal MF, spiculitic MF, onkolitic MF, foraminiferal MF, crinoid MF, peloid MF, organodetrital MF, coquina MF, biomicritic MF and coral MF. The most characteristic feature of the sequence is the abundance of algal MF, which comprises more than 30% of limestones. The algal assemblage in this microfacies consists of 29 taxa (see 24), the most important of which is the species Calcifoliurn okense (Codiaceae) and such genera as: Kulikia, Nanopora, Kamaena (Dasycladaceae) as well as the Stachaeiinae (problematic Rhodophyta). Quantitative and qualitative differentiation of MF spectrum (Text - fig. 4) allows to distinguish particular limestone complexes. Typical vertical sequence of microfacies has been determined by means of Markov analysis (Text - fig. 5). The sequence starts and finishes with al gal MF, which has been developed in quiet, lagoonal areas, protected by barriers of shoals, formed by crinoid and organodetrital banks. The offshore facies, occurring in the middle part of the cycle, is represented by foraminiferal MF. During episodic lowering of sea level, the area of banks was either emerged or covered by shallow-water onkolitic, spiculitic and peloid microfacies. Analysis of the whole uppermost Visean sequence, as well as microfacies characteristics of limestones, indicate distinct similarities in sedimentary conditions prevailing in the Lublin Coal Basin, and in the Yoredale facies of northern England and southern Scotland.