CLASSICAL LOCALITY OF THE FOSSIL FLORA IN THE BELAYA KALITVA FORMATION (UPPER BASHKIRIAN, CARBONIFEROUS) OF THE DONETS BASIN (UKRAINE)

Abstract

The results of the study of the fossil flora from the locality near Roven’ky Town (south part of the Luhansk Region, Ukraine) are presented in the article. Plant fossils are found in the sediments of the Belaya Kalitva Formation (Upper Bashkirian, Middle Carboniferous). Information on the findings of the fossil flora in the vicinity of Roven’ky Town is known since the second half of the XIX century. O.V. Gurov, O.F. von Geller, M.D. Zalessky, A.M. Kryshtofovich, О.F. Chirkova, and K.Y. Novik had collected and studied the plant fossils from the vicinity of modern Roven’ky Town. Part of the collections studied by M.D. Zalessky probably comes from the locality Roven’ky. The following flora was determined from this locality: Cyperites bicarinatus, Lepidodendron sp., Lepidostrobophyllum lanceolatum, Stigmaria ficoides, Annularia radiata, Asterophyllites charaeformis, Calamites sp., Calamariophyllum kidstoni, Pinnularia cappilacea, Sphenophyllum cuneifolium, Alethopteris decurrens, Alethopteris urophylla, Neuropteris heterophylla, Paripteris pseudogigantea, Cyclopteris orbicularis, Eusphenopteris sp., Mariopteris nervosa, Samaropsis sp. Sphenopsids (mainly the root systems Pinnularia cappilacea) and pteridosperms Neuropteris heterophylla and Mariopteris nervosa are dominate. A characteristic feature of this fossil plant assemblage is the almost complete absence of the lycopsid axes and a very small number of the arborescent sphenopsids axes. Ferns are also not found. The studied plant-bearing sediments should be attributed to the Sphenophyllum majus Zone. The structure of the fossil flora probably indicates that the semi-aquatic sphenopsid communities grew in the coastal part of the basin where the plants were buried. Pteridosperms and possibly arborescent lycopsids communities were apparently replaced the sphenopsids in deep inland.