Funda Akgün

Palynostratigraphy ofthe coal-bearing Neogene deposits graben in Büyük Menderes Western Anatolia

Abstract The east-west striking Buyuk Menderes graben is one of the major structures of the Aegean grabensystem in Western Anatolia. 169 samples taken from eight localities in the coal - bearing Neogene deposits of this graben have been processed for palynomorphs of which 49 were suitable for pollen analysis. The palynomorph associations include 5 pteridophytic spores, 8 gymnospermous and 32 angiospermous pollen taxa. This high degree of diversity allows recognition of detailed age divisions in the graben filling. The presence of the two palynomorph associations has been recognized on the basis of quantitative and qualitative contents of palynomorphs. The first palynomorph association occurs in the Soke, Sahinali, Kulogullari, Kosk - Bascayir coal horizons, and the Aydin-Incirliova, Kosk-Kizilcayer and Nazilli-Haskoy lower coal horizons. Samples from these localities, which are characterized by the predominance of Pinus haploxylon - type Alnus, Quercus, Castanea, Myrica and Cyrillaceae, are the Middle Miocene (equivalent of early-middle Serravalian) in age. The second palynomorph association, which is the late Middle Miocene-earliest Late Miocene (equivalent of latest Serravalian to earliest Tortonian) in age, is characterized by the presence of low numbers of subtropical elements and the increase in the amount of representatives of herb pollen. The upper coal horizons of the Kosk-Kizilcayer, Nazilli-Haskoy and Saraykoy-Sazak coals are of this age. By the palynological age determinations, it is clear that the Neotectonic activity started before the formation of the Middle Miocene coals.

Pseudodioon akyoli gen. et sp. nov., an extinct member of Cycadales from the Turkish Miocene

Fossil cycadalean leaves recorded from the Miocene plant assemblage of Soma, western Turkey, are described and assigned to an extinct genus and species, Pseudodioon akyoli. Leaf macromorphology suggests affinity with members of the Zamiaceae (subfam. Encephalartoideae), particularly with modern Dioon. Micromorphological features on the other hand indicate affinity with modern Cycas (Cycadaceae). Ordinary cells on the adaxial epidermis are isodiametric and are not differentiated into thick- and thin-walled cells. This is similar to Encephalartoideae-like fossils reported from the Cenozoic of the Northern Hemisphere, and even from the Mesozoic. Shared macromorphological traits of P. akyoli and other coeval Encephalartoideae-like fossil cycadalean leaves from Europe suggest that an extinct group of cycads inhabited southern Europe from the western part of Turkey, through Greece and France to Switzerland in the north during the Oligo-Miocene.

Miocene palynoflora of the Kocaçay and Cumaovası basins: a contribution to the synthesis of Miocene palynology, palaeoclimate, and palaeovegetation in western Turkey

Palynofloras of the Kocacay and Cumaovasi basins in western Turkey that belong to a time-span from the late Early to late Middle Miocene (the late Burdigalian-Serravallian) are studied and compared with published palynofloras of Europe and Turkey. Palynological data and numerical climatic results obtained by the coexistence approach indicate palaeoclimate changed from warm subtropical to temperate during the late Burdigalian-Serravallian. Moreover, the palaeoclimates of the Kocacay and Cumaovasi basins are compared with continental palaeoclimatic records of coal-bearing sediments in western Turkey and current temperatures in the Izmir region. According to this comparison, palaeoclimatic results of these basins and other localities in western Turkey show a distinct difference as a result of orographic change. The palaeovegetation in the Kocacay and Cumaovasi basins during the studied time-span was affected by palaeotopography and palaeoclimate. In these basins mixed mesophytic, coniferous forests, and swamp palaeovegetation generally predominated during the late Early-early Middle Miocene. The role of the herbaceous taxa increased at the end of the late Middle Miocene (the Serravallian) in the Kocacay and Cumaovasi basins. It is obvious from the palynomorph data of these basins that grassland palaeovegetation started to expand in the late Middle Miocene. Unlike in Central Europe, where late Burdigalian and Langhian represent a period of outstanding warmth, the so-called Mid-Miocene Climatic Optimum, cold month mean temperatures reconstructed in this study point to an ongoing cooling trend, already from the late Burdigalian onwards, possibly related to increasing terrestrial conditions in the study area.