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Karbon Sudetów w świetle nowych wyników badań biostratygraficznych

Górecka-Nowak Anna, Muszer Jolanta, Maćko Adrianna

Przegląd Geologiczny

2025

Vol. 73, nr 9

776--783

The paper presents geological implications of new results of biostratigraphic studies (mainly palynostratigraphic) of Carboniferous rocks from the central part of the Sudetes. They brought important changes in stratigraphy, most often showing younger age of studied rocks than it was believed earlier. The onset of sedimentation in the Intra-Sudetic Basin, initially in the continental environment, was not earlier than in the middle Visean. Marine sediments, previously considered to be a manifesta¬tion of the Late Viseanian transgression, were found to be diachronic (from the late Visean to the Namurian C). Among profiles of the Szczawno Formation and its lithologic equivalents that were previously considered to be Upper Visean, only two profiles: Ptasia Góra in the Intra-Sudetic Basin and Paprotnia in the Bardo Unit, represent the uppermost Visean. Most of the other profiles from the Wałbrzych region turned out to represent the Namurian A (Serpukhovian) or even Namurian B and C (Bashkirian age) in the case of some profiles in the Sowie Mountains Massif. The late Visean-early Namurian (Serpukhovian) age range also encompasses marine mudstones from the southern part of the Świebodzice Unit, which were previously considered Late Devonian. This discovery is of great importance for the model of development of the Świebodzice Unit. Consequently, the timing of the marine sedimentation in different geological units of the middle part of the Sudetes should be revised. The coal bearing rocks of the Wałbrzych Formation, analysed in the study, are of Namurian A (upper Serpukhovian and lower Bashkirian) age. The Biały Kamień Formation was included in the Namurian B and C and Westphalian A (Bashkirian), the Żacler Formation - in the Westphalian A-C (Bashkirian and Moscovian), and the Glinik Formation - in the Westphalian D(?). The documentation of successive miospore zones from VF to OT(?) indicates that there are no stratigraphic gaps in the Upper Visean-Westphalian D (?) interval in the Intra-Sudetic Basin. The problem of the chronostratigraphic significance of miospores dating the Walchia shales in the Intra-Sudetic Basin and the need to reinterpret the location of the Carboniferous/Permian boundary are also discussed.

New palynostratigraphic data from the Namurian Biały Kamień Formation in the northern part of the Intra-Sudetic Basin (SW Poland)

Maćko Adrianna, Górecka-Nowak Anna

Geological Quarterly

2024

Vol. 68, No. 3

art. no. 32

Palynostratigraphic studies of the Carboniferous strata of the Biały Kamień Formation, outcropping in the northern part of the Intra-Sudetic Basin, are reported. This formation had been earlier assigned to the Upper Namurian and Lower Westphalian A on the basis of macrofloral and palynological data (Gothan and Gropp, 1933; Górecka, 1969) but these results needed checking against the modern international miospore zonation. We described many taxonomically diverse miospore assemblages from these rocks, which allowed to include them into two miospore zones, of Crassispora kosankei–Grumosisporites varioreticulatus (KV) and Raistrickia fulva–Reticulatisporites reticulatus (FR). These zones are correlated with part of the interval from the upper part of the Namurian A up to the Namurian C. The miospore zone Cirratriradites saturni–Triquitrites sinani (SS), identified by Górecka-Nowak (1987, 1995) from the Grzędy IG 1 borehole, extends the age range of the Biały Kamień Formation from Upper Namurian A to Lower Westphalian A. The documentation of these zones together with previous results of palynostratigraphic studies of the underlying Wałbrzych Formation corroborates the record of miospore zones of the Serpukhovian and Bashkirian in the Intra-Sudetic Carboniferous and suggests that there is no stratigraphic gap between the Wałbrzych and the Biały Kamień formations.