Palaeoflora and Climate of Lignite-bearing Lower-Middle Miocene Sediments in the Seyitomer and Tuncbilek Sub-basins, Kiitahya Province, Northwest Turkey

Lower-Middle Miocene successions from Kutahya province (Seyitomer and Tuncbilek sub-basins) were analyzed to reconstruct the palaeoclimate and vegetation of the period. A rich coniferous forest formed the dominant components among sporomorphs and consisted mainly of undeterminable Pinaceae, Pinus haploxylon type, Pinus diploxylon type, Picea, Cedrus, Cathaya, Keteleeria and Podocarpus. Pollen data also indicate the presence of some fern taxa (Osmunda, Polypodiaceae, Schizeaceae) Selaginella and Lycopodium. Cupressaceae frequently occur in all samples from both subbasins, arid form part of the mixed forest assemblage. Two woody plants Castanea-Castanopsis and evergreen Quercus predominate in the assemblages as well. The reconstruction of palaeoclimate is based on the Coexistence Approach (CA) method and documents subtropical climate with cyclic variation in the sediment sequence. The vegetation does not show a clear change through the sequences studied. Small changes in the quantity of pollen taxa (e.g., thermophilous and arctotertiary) indicate small-scale cyclic temperature and precipitation oscillations during the deposition of the sediments. Using CA, seven palaeoclimate parameters were estimated. Quantitative palaeoclimate data indicate mean annual temperatures of 17-18 degrees C, with winter temperatures of 8-10 degrees C and summer temperatures of 27-28 degrees C. Mean annual precipitation exceeded 1200 mm. The driest month precipitation was between 20 and 25 mm, the wettest month precipitation most frequently ranged between 200 and 250 mm and the summer precipitation was 100-150 mm. These values imply that the Kutahya area was warm and received more precipitation during the Early-Middle Miocene than in modern times.