Fito- i palinostratygrafia karbonu okolic Warszawy

Abstract

Przedstawiono florę i mikroflorę karbońską z 10 otworów wiertniczych okolic Warszawy. W wyniku analizy materiału roślinnego określono stratygrafię karbonu wydzielając w tym rejonie następujące podpiętra: wizen górny, namur A, namur B-C, westfaI A, B i C. Badaniom paIinologicznym poddano 262 próbki. Zawarta w nich·mikroflom pozwoliła ustalić w badanych otworach poziomy sporowe I - VII z określeniem wieku osadów. Flora karbońska w badanych otworach była nieliczna, jednakże zespół gatunków zawierał skamieniałości przewodnie i charakterystycze. Na ich podstawie udokumentowano w jednym otworze utwory namuru A, w pozostałych westfaIu A i B oraz przypuszczaInego westfalu C. Przewodnie i charakterystyczne gatunki mikro- i makroflory zostały zilustrowane na tabl. I - VII.

PHYTO- AND PALYNOSTRATIGRAPHY OF THE CARBONIFEROUS OF THE WARSAW AREA

The paper presents the results of phytostratigraphic and palynostratigraphic studies cf Carboniferous rocks from of boreholes made in the vicinities of Warsaw (Fig. 1). The Carboniferous is here represented by the Dinantian (UpperVisean) and Silesian (the interval from the Namurian A to Westphalian C).

Palynological (miospore) studies covered 262 samples of core material from cored intervals of the Carboniferous. The obtained microflora made it possible to distinguish spore zones I - VII in the studied sections. The zones, originally differentiated for the central-eastem Poland (H. Kmiecik, 1978), correspond to the Upper Visean, Lower and Upper Namurian A, Namurian B-C and Westphalian A, B, and C (Table I). All the spore zones are briefly characterized here and their correlation with subdivisions of the Carboniferous, used in other parts of Poland and western Europe, is given. Table 2 shows ranges of miospore species more important for stratigraphy as well as horizontal extent of deposits representing individual stratigraphic units.

The studied rocks are generally poor in floral remains but, nevertheless, the assemblage of the identified species comprises some guide and characteristic fossils. The fossils evidence the presence of the Namurian in one of the borehole sections, and of the Westphalian A and B and presumably Westphalian C in the remaining ones. The floral assemblages from individual boreholes are characterized and the floristic criteria for differentiation of substages of the Carboniferous in that ·area are given.

The palynological and floristic studies carried out by the authors made possible a detailed subdivision of Carboniferous rocks in the vicinities of Warsaw. A more accurate sampling of cored intervals for palynological studies resulted in more precise delineation of boundaries of stratigraphic units of the Carboniferous (spore zones). The floristic studies, based on less numerous fossils, gave support to the results of palynological analyses and they supplemented the obtained image of vegetational cover of this part of Poland from the Carboniferous times. The results obtained with the use of both methods best evidence the Westphalian A, Band C, whereas the Upper Visean and Namurian have only palynological record (with the exception a the Lower Namurian, the palynological dating of which is confirmed by well preserved floral remains).

The guide and characteristic species of flora and microflora are figured in Tables I - VII.