FOSSIL FLORA FROM THE UPPER TRIASSIC GRABOWA FORMATION (UPPER SILESIA, SOUTHERN POLAND)

Silesia, Poland). Geologorum Poloniae, Abstract: Upper Triassic fossil plants are well documented from the Keuper of Europe. Carnian and Rhaetian flo-ras are rich in a variety of plant taxa, whereas in comparison, the Norian is limited to a few localities with poorly preserved fossil plant communities showing low diversification. The Norian Grabowa Formation in Zawiercie-Marciszow, Upper Silesia, southern Poland, contains fossils of arborescent gymnosperms, including petrified coni-fer trunks. In this study, we present a fossil plant assemblage, containing fragmented plant parts in multiple forms of preservation, i.e., permineralised trunks and rooting structures, stems compressions, dispersed cuticles, and me-gaspores. Analysis of the macromorphological characters proved the presence of gymnosperms, including the ar-borescent conifer Agathoxylon cf. keuperianum, known already from this locality from fragments of charcoalified wood. Sphenophytes are represented by disarticulated stems of Equisetites sp., and Neocalamites sp. The variation in plant fossils indicates the possibility of higher plant diversity. Analysis of cuticles, macerated from different plant-bearing lithologies, revealed a variety of conifer foliage, expressed as five cuticulae dispersae morphotypes (needle-leaf Elatocladus-type and scale-leaf Pagio- Brachyphyllum-like). Plant fossils at Zawiercie-Marciszow are preserved in calcareous mudstones and micritic limestone concretions, developed in a fluvial environment. The presence of sphenophyte stems (Equisetites and Neocalamites) indicates that local conditions were more humid and suitable for spore-producing plants, appearing in the mid-Norian tectonic-pluvial episode, recorded in the Grabowa Fm.

Automated summary

Fossil plant assemblage from the Norian Grabowa Formation in southern Poland indicates low plant diversity compared to Carnian and Rhaetian flo-ras. The presence of gymnosperms and sphenophytes suggests variation in local conditions.