Radiometric and palynological data of the Upper Oligocene-Lower Miocene Soma Formation from the Kalkım-Gönen Basin yield new results related to age and palynological contents. In this study, Upper Oligocene strata from the Daniş-ment and Linfa areas and Lower Miocene strata from the Bengiler area were sampled palynologically and for radiometric dating. The Danişment assemblage, which is older than the Linfa assemblages, mainly contains coniferous and evergreen to deciduous mixed mesophytic forest elements. Relatively high quantities of the altitudinal plants Picea and Abies, indicate a cooler palaeoclimate. The Linfa associations mainly include coniferous and riparian elements. Pollen of the riparian plant Alnus and Taxodiaceae indicative for the swamp forest community was predominant, probably as a result of a high lake level. There is a hiatus during the Oligocene-Miocene transition, probably showing a non-depositional phase and sea-level fall indicating the Mi-1 glaciation event. Higher in the sequence, the Aquitanian Bengiler sediments include high amounts of coniferous forest elements as well as components indicative for the evergreen and deciduous mesophytic forest and also riparian forest and swamp forest. Due to presence of thermophilous taxa Reveesia, Mastixiaceae and Arecaceae, a warm and humid palaeoclimate is inferred according to quantitative analyses using the Coexistence Approach.

This study presents the micropalaeontological data (palynomorphs and ostracods) including index taxa to assign a precise age, and the palaeoecological evolution of the Aspiras Basin, south‐east Kastamonu, northern Anatolia. The succession may informally be divided into a lower part including rich lignites interbedded with fine‐grained sediments and an upper part which comprises lignite‐free deposits such as mudrocks with dense gypsum and rare limestones. The sediments of the lower part were deposited in a wetland (i.e. peat‐forming environment) showing oscillations of the lake level, whereas the upper part indicates the shoaling or closing phase of the lake. Early Miocene age is assigned to the Aspiras Basin due to the presence of index taxa such as Leiotriletes maximus, Dicolpopollis kockelii, Intratriporopollenites instructus, Caryapollenites simplex, and ostracods Pseudocandona praecox and Potamocypris gracilis. Moreover, a new species of ostracod, Heterocypris aspirasensis, has been discovered. In the lowermost part of the succession, palynomorph spectra are dominated by spores such as Leiotriletes maxoides, L. maximus, and Verrutacosporites alienus while diverse pollen types, notably conifer pollen, attain high abundances further up in the succession. In the forested environment, the mixed mesophytic plants were less diverse. Low quantities of herbaceous taxa such as Ephedra sp., Poaceae, Amaranthaceae, Asteraceae‐Asteroideae, and Asteraceae‐Cichorioideae indicate the limited occurrence of open areas. During the Early Miocene, a warm and moist climate prevailed according to quantitative palaeoclimate data and the presence of the mega‐mesothermic taxa such as Taxodioideae, Mastixiaceae, Engelhardia, Sapotaceae, and Calamus.

In this study comprehensive palaeofloristic data of lower Miocene deposits from the Soma Basin, western Anatolia is presented considering the stratigraphical concept. The sediments of the basin, derived from outcrop sections, were deposited in the terrestrial environment. The basin includes three different successions: lower and middle lignite successions of the Soma Formation and upper lignite succession of the Deniş Formation. In this paper, we address the early Miocene palaeoecology via pollen and leaf assemblages from the Soma Basin, dated precisely using radiometric data. High percentages of Cupressaceae in the lower lignite succession of the Soma Formation, and minor quantities of elements such as Carya, Nyssa, Myrica, Ulmus and Salix reflect a local riparian and swamp vegetation. Marls overlying the lower lignite succession represent an environment close to the source area, with a variety of flora. During the deposition of middle lignite succession wet conditions played an essential role in the swamp forest fostering some distance transport of pollen which reflect the mesophytic forest vegetation as well as higher altitudes in the hinterland. The high percentages of lacustrine plankton Botryococcus and presence of Spirogyra in the upper lignite succession of the Deniş Formation imply a shallow water environment with less rainfall surrounded by evergreen and deciduous mixed forest.

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