THE EARLY DEVONIAN BIOCOENOSIS OF THE CLASTIC SEDIMENTS FROM THE HOLY CROSS MTS., POLAND

Sediments from the Bukowa Góra Quarry (Holly Cross Mts. Poland) reveal an abundant record of fossil plants, preserved as both micro- and macrofossils and a palynomorph assemblage dominated by phytoclasts and miospores. The age of the deposits was assessed on the well-preserved miospore assemblage using as the AP (Acinosporites apiculatus – Grandispora protea) Oppel Zone, strictly the Pro. Interval Zone corresponding to the Emsian (Lower Devonian). This level can also be tentatively correlated with the patulus Condont Zone. The following taxa were observed: Acinosporites apiculatus, Ancyrospora kedoe, Dibolisporites echinaceus, Grandispora protea, Hystricosporites corystus, and H. microancyreus. Acritarchs were rare; only few specimens of Veryhachium, Micrhystridium were found.

Among the microfossils, some specimens closely resemble Tortotubus protuberans, Ornatifilum lornensis (considered as an early developmental stage of the previous) and Laevitubus. The suggested fungal identity cannot be considered secure neither for these filaments nor for those of the Bukowa Góra Quarry. Chemical analyses are planned in order to determine the presence or absence of chitin and its distribution in the cell walls, which could help to clarify the affinities.

Plant macrofossils are mainly preserved as coalified compressions of fragmented and isolated plant parts and organs, i.e. stems, sporangia. The assemblage is dominated by specimens resembling Drepanophycus sp. Other remains (less numerous) show similarities to Psilophyton spp. A small fraction is represented by specimens of Leclercqia- and Zosterophyllum-types of remains.

The phytoclasts assemblage consists of non-opaque elements, dark-brown-pale brown in color, with a sharp outline and a high angularity indicating a relatively short transport and a high sedimentation rate. The observed phytoclasts are not degraded, which is a typical feature of proximal, oxic environments. This finding added to the occurrence of plants and possible fungi suggest a terrestrial environment for the Bukowa Góra Quarry sediments.

This project was financially supported by NCN grant nr 2015/19/B/ST10/01620 to P. Filipiak, (University of Silesia, Poland).

University of Silesia in Katowice, Faculty of Earth Sciences, Będzińska 60, 41-200 Sosnowiec, Poland