Paleontological investigations of the Plio-Quaternary beds of the Velenje depression

Abstract

Paleontological research of the Velenje coal measure sequence includes the palynological examinantions, the investigations of malacofauna and the analyses of diatoms. The pollen analyses confirmed the Pliocene age of the coal measures. The majority of the hanging wall strata belong to Upper Pliocene, its topmost part to Villafranchian. The coniferous type “Taxodium flora” in the lower part of the Pliocene sequence yields place upwards to the oscilatory presence of foliage plants. The analysis of malacofauna permitted the identification of lower horizon, encompassing the coal seam and a portion of succession just above it, marked by the association of Valvata (Cincinna) interposita, Prososthenia ovata and Planorbis hians. An upper horizon, which is separated from the former by a thick succession of limnic sediments, is characterised by Melanopsis spinicostatus, Bithynia sp., Pyrgula sp., Prososthenia n. sp. and Planorbis n. sp. The study of diatoms proved the presence of aquatic (limnic) facies. The perifitonic species prevail just above the coal seam, followed up by an euplanctonic suite. No diatoms were detected just at the top of the sequence in Villafranchian. The paleontological investigations included also a short account of macroflora, the analyses of ostracods and a review of mammals’ rests.