Özet:

In this study, the lignite-bearing Yoncalı formation between Yozgat and Sorgun, in central Anatolia has been palynologically examined. Based on 37 outcrop samples, quantitative palynological studies recognized 64 genera and 136 palynoflora species in the palynological assemblage, which indicated a Middle-?Late Eocene age. This paper also presents a quantitative palaeovegetation and palaeoclimate reconstruction for the Middle-?Upper Eocene coal occurrences of Central Anatolia on the basis of palynomorph assemblages. The diversified floral and ecological characteristics of the pollen taxa indicates that the Middle-?Upper Eocene formations in central Anatolia were characterized by the presence of a complex mangrove swamp with contributions by Nypa, Pelliciera, Avicennia, Diporites iszkaszentgyörgyi and dinoflagellate cysts which reflect warm climatic conditions. Behind the mangrove zone, pollen of Restionaceae, Ephedraceae, Mauritia, Proxapertites (Araceae) and Longapertites (Arecaceae) as well as the fern Acrostichum aureum occur. Lowland-riparian and montane elements are characterized by the dominance of Myricaceae, Symplocaceae, Icacinaceae, Quercus, Pinus and Castanea. Swamp-freshwater elements are represented by Sparganiaceae, Nymphaceae, Taxodiaceae, Cupressaceae and Nyssa as well as fern spores such as Osmundaceae and Gleicheniaceae. The calculations were performed with the help of the `Coexistence Approach´ method to climatically evaluate palynoflora from the Yozgat-Sorgun area. The obtained results have been compared to data derived from the application of the Coexistence Approach to other, already published Central Anatolian palynofloras of the same age. The results of the climatic inferences suggest that the palaeoclimatic conditions were in the megathermal zone (mean annual temperature of 24.8-25 ºC), megatherm/mesotherm intermediate zone (mean annual temperature of 23.1-24.8 ºC near the coast) whereas mesothermic (mean annual temperature of 16.5-23.1 ºC) conditions prevailed in the montane region. Likewise, the results of mean annual range of temperatures indicate the influence of the Indian ocean, which enabled the development of the mangroves.

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