ARHIVELE OLTENIEI - Universitatea din Craiova

The genetic control factors of the lignite types from western Oltenia 371During the Lower Dacian, in the lignite deposits, it can be noticed thepresence of pollen of Sapofaceae, Cyrilaceae, Melvaceae and of dinoflagelates,such as Leptodinium, Millioydodinium and Pyxidinopsis.For the Dacian lignite deposits, the depositing environments can berevealed through palynological analysis. Thus, for the areas located below thewater, it can be noticed the presence of spores of aquatic ferns, such as: Azolladonica, Azolla tegeliensis and Salvinia.The determined polynic specters 8 emphasized a closing of the lagoonformation represented by the pollen of Taxodium and Glyptostrobus, at which itcan be added the existence of reeds expressed by the pollen of Typha, frommany altitudes. Thus, it appeared a coniferous area dominated by Picea, Abies,Tsuga and Cedrus, and their pollen was carried by the air currents in the coalgeneratingmarsh and a hornbeam-beech forest and a deciduous forest withQuercus, Ulmus, Tilia, Petrocarya, Juglans and Carpinus.In the lagoon formation, there persisted some groups of Taxodium andGlyptostrobus. he oscillations of the level of the lake determined the presence ofsteppe vegetation through the pollen of Artemisia and of Chenopodiaceae(Atriplex and Kochia).e) The coal-like facieses factorThe qualitative features of the original peat and, thus, of the coal bedsresulted from it depend on many factors that join the category of coal-likefacieses factor: the accumulation types of the vegetal material; the communitiesof peat-generating plants; the depositing environment; the marshes supply withnutrients; the value of the pH in the water of the marshes; the redox potential(Eh); the peat temperature; the bacterial activity.The accumulation type determines one of the most important features ofcoals – the ash content.The autochthony of the coal-generating vegetation from the Olteniabasin cannot be contested and the respective vegetation lived in 0-3 m deepwater. This is first noticed on the basis of the research made at Timi şeni inRovinari Coal Field whwre, in certain fossil areas, it was found only one species:Salix pliocenica. Osmunda regalis found by the same author at Timişeni,distributed in the mountain forests, as well as Scolopendrium that lived on theshore of the lakes, can be considered “in situ” accumulated.The fact that at the top of the VII lignite bed from Lupoaia and Roşiuţamining exploitations from the Motru Valley there were found numerousimpressions of only one species, which are attributed to Byttneriophyllumtiliaeformis form, supports this interpretation.8 Petrescu et al., Paleoclimatical significance of the palynological approach thePliocene, deposits of Lupoaia, in “Studies of Babeş-Bolyai University”, Geol. Geog. XXXIV,Cluj, 1989, p. 23-26.