Age revision of Carboniferous rocks in the northern part of the Intra-Sudetic Basin (SW Poland) based on miospore data.

Abstract

Palynostratigraphic studies of the Carboniferous strata of the Szczawno and Wałbrzych formations, outcropping in the vicinity of Wałbrzych in the northern part of the Intra-Sudetic Basin, are reported. Rocks of the Szczawno Formation in a section near Konradów had earlier been assigned to the Upper Visean, while rocks of the Wałbrzych Formation in the Biały Kamień section were included to the Lower Namurian [the Stenozonotriletes triangulus–Rotaspora knoxi (TK) Miospore Zone]. This study describes abundant palynological material with many taxonomically diverse miospore assemblages from these rocks, allowing precise palynostratigraphic conclusions. These showed that the rocks of the Szczawno Formation studied should be referred to the lower part of the Serpukhovian [Verrucosisporites morulatus (Vm) Subzone], correlated with the lowest Namurian, while rocks of the Wałbrzych Formation from Biały Kamień belong to the Lower Bashkirian [Lycospora subtriquetra–Cirratriradites rarus (SR) Subzone], correlated with the Upper Namurian A. These results indicate that the rocks from both sections studied are younger than they were earlier believed. This revises the age of the Szczawno and Wałbrzych formations in the northern part of the Intra-Sudetic Basin which belong to four miospore zones, from Vm to SR, corresponding to the Serpukhovian and lowermost Bashkirian (Namurian A corresponding to the Pendleian to Alportian of British chronostratigraphy).