The Galatean volcanics comprises Early Miocene (18 to 20 Ma) intermediate-acid lava flows and associated pyroclastics and Late Miocene (9 to 11 Ma) alkali basaltic lava flows. The Early Miocene volcanics mainly consist of trachyandesites and dacites with minor rhyolite and alkali basalts [40]. The Galatean volcanics are overlain unconformably by fluviolacustrine facies of the Pazar formation.

The fluviolacustrine sequence of Pazar formation shows lateral and vertical lithological variations. The lowest part of the sequence consists of conglomerates, lahar and tuff layers, which are exposed only in the northern part of the basin with a thickness exceeding 300 m. Upwards, the sequence passes into an alternation of sandstone, siltstone, claystone, marl and limestone with thin coal intercalations. Its thickness is estimated to be more than about 600 m. [37]. The top of the sequence consists of lacustrine marly limestones which are exposed in the southern part of the basin. These limestones represent the deepest part of the lacustrine sequence. The Pazar formation is represented by a southward-dipping sequence in the Pelitçik basin. On the basis of the dolomite stoichiometry and mineral paragenesis, Süzen and Türkmenoğlu [33] claimed that the depositional conditions of the Pelitçik basin suggest a shallow, quite lacustrine environment with fresh to slightly saline and alkaline water chemistry.

Two distinct eruptive cycles of volcanic activity are observed within the Galatean Volcanic Province. Radiometric age determinations indicate an age of 18 to 20 Ma for the older cycle while the younger cycle is represented by alkali basalts of 9 to 11 Ma [18] and [40]. Since the study of Toprak et al. [37] showed that the Pelitçik basin was formed immediately after the generation of Daskamun and Ovacık volcanic complexes and basin-fill deposits conformably overlie these complexes, the age of initial deposition within the Pelitçik basin can be correlated with the age of Daskamun (18 Ma) [40] and Ovacık complexes (20 Ma) [37]. Furthermore, the fluviolacustrine basin-fill deposits interfingering with volcanics are capped by the Late Miocene (9 to 11 Ma) alkali basalt flows [40]. Accordingly, the age of fluviolacustrine basin-fill deposits is Early to Middle Miocene.

Seven pollen taxa are assigned to this association, which mainly includes pollen derived from Salix, Cupressaceae and Taxodiaceae (Fig. 3 and Fig. 4). Cupressaceae and Taxodiacea pollen cannot be identified into genus level, which may represent different environments. Since the relative abundance trend of Cupressaceae resembles those of the Taxodiaceae, it is assumed that Cupressaceae were represented by taxa requiring warm and humid conditions, such as those (e.g., Chamaecyparis) living today in wetlands along the Gulf Coast of the United States [27]. Salix is the most abundant taxa in swamp forest association and the highest relative abundance of this typical swamp genus is revealed around 48 m level (Fig. 3). Also included in this association are some trees and shrubs, such as Nyssa, Alnus, Cyrillaceae-Clethraceae and Myrica, which grow in periodically flooded riparian environments. These palynomorphs are present in low quantities and show no significant variation in abundance throughout the studied section (Fig. 3).

This association comprises 30 identified taxa and constitutes between 24 and 89% of the total pollen assemblage (Fig. 3 and Fig. 4). Pollen in this association is derived from conifers and other evergreen plants but also deciduous angiosperm trees and shrubs. The association is dominated by conifer pollen, which are undifferentiated due to poor preservation. Pollen from deciduous trees such as Ulmus, Carpinus orientalis, Carya and Quercus are also frequent. Minor constituents include, among others, Pterocarya, Juglans, Zelkova, Hamamelidaceae and Oleaceae. Other significant taxa include Engelhardia and Araliaceae. The warm temperate taxa included in this group grew in different habitats. Thus, the quantitative variations mainly serve to interpret the paleoclimate.

This association consists of seven taxa mainly constituted of ground-cover vegetation in the mesophytic forest (Fig. 3 and Fig. 4). Polypodiaceae and Amaranthaceae/Chenopodiaceae are the dominant groups in this association. The highest relative abundance of Polypodiaceae was found at levels 0 to 15 m and that of Amaranthaceae/Chenopodiaceae was at 50 and 55 m (Fig. 3). Other taxa contributing to this association are Asteraceae/Asteroideae, Brassicaceae, Dipsacaceae, Caryophyllaceae and Apiaceae. These palynomorphs are present in low quantities.

This association includes palynomorphs from plants that prefer mainly moist environments (Fig. 3 and Fig. 4). In the studied section this association varies between 3 and 39% (Fig. 4). Taxa included are Poaceae, Sparganium and Potamogeton. Sparganium occurs in almost every sample, comprising up to 40% of this association. The aquatic taxon Potamogeton is present only at the 53 m level. The individual elements of the family Poaceae are difficult to identify as the pollen grains of different genera do not show significant morphological differences. As regard to palynological assemblage identified from Pelitçik section, it is most likely that the Poaceae would have been represented mostly by reeds and other hydrophilic graminoids rather than xeric grasses, like in the sedge swamp of Middle-Polish Beds [23].

The freshwater algae Botryococcus, Ovoidites, Spirogyra and Mougeotia are included in this association. They are present in almost every sample.

If a pollen-bearing locality is not found with intercalated marine sediments, in association with mammalian faunas or in sections with radiometric or magnetostratigraphic measurements, the age control is often poor and this makes temporal comparisons complicated. Therefore, well-dated palynofloras from Turkey and Europa are selected to compare with Pelitçik palynoflora.

Benda et al. [2], [3], [5], [6] and [7] carried out extensive palynological investigations in the Cenozoic of Turkey and established biostratigraphic classification of the Late Oligocene-Pliocene fluviolacustrine deposits in western Turkey. Their sporomorph associations and sporomorph biostratigraphy result from the quantitative study of numerous samples from all over Turkey. Five sporomorph associations (biozones) are distinguished in the Neogene namely, from older to younger, Kale, Eskihisar, Yeni Eskihisar, Kızılhisar and Akça Associations [2] and [3]. These sporomorph associations are later correlated with the marine fossils and radiometric dates to establish a Neogene palynostratigraphic biozonation [4]. Benda et al. showed that their palynostratigraphic biozonation can be used for the entire eastern Mediterranean region [4], [5] and [6].

The Eskihisar Association covers a time interval from about 19–20 Ma to 14–15 Ma and Yeni Eskihisar Association from about 14.8 to 11.1 Ma [4], [30] and [31]. The (radiometrically constrained) age range of palynomorph assemblage identified in this study corresponds to the Eskihisar and Yeni Eskihisar Associations. The Eskihisar Association is mostly characterized by high percentages of Pityosporites (Pinus indet., Pinus haploxylon-group, Picea), inaperturate forms (Taxodiaceae/Cupressaceae) and by low percentages of Ulmipollenites undulosus (Ulmus), Polypodiaceae, Polyvestibulopollenites verus (Alnus), triatrioporate pollen types (coryphaeus: Engelhardia or myricoides-bituitus group: Myricaceae). The Yeni Eskihisar Association is characterized by dominance of ‘asper-types’ within the quercoid pollen forms and an increase of the stigmosus-group (Liquidambar) and areolatus-group (cf. Palmae) [2]. The transition from Eskihisar to Yeni Eskihisar associations is represented by an increase in Quercus, Ulmus and Graminae pollen [3]. In the Pelitçik samples, Pinus and Ulmus dominates with lesser amounts of Quercus and Carya and, the mean percentages of Poaceae and Chenopodiaceae-Amaranthaceae pollen are 2.5 and 6.8% respectively. This composition suggests that Zone 2 of Pelitçik Basin may belong to Yeni Eskihisar biozone.

Yavuz-Işık [44] investigated a late Early-Middle Miocene coal-bearing sedimentary sequence from the Seyitömer Basin (western Anatolia), which is dated by mammal fossils, and recognized two pollen zones. Zone 1 is characterized by predominance of Pinus and Cedrus while Zone 2 is characterized by predominance of deciduous Quercus and evergreen Quercus and a marked reduction in representation of Taxodiaceae. Zone 2 of Seyitömer palynomorph association is similar to Zone 2 of Pelitçik, except the dominance of Taxodiaceae and Cedrus. The diversity of the other taxa between two associations does not differ much, but the abundance of taxa varies. A Taxodium swamp was well developed in Seyitömer as represented by rich Taxodiaceae and Cupressaceae pollen whereas a mixed mesophytic forest was well developed in Pelitçik as represented by high frequencies of Carpinus, Ulmus, Carya, Quercus and Pinaceae pollen. The presence of megathermic elements such as Euphorbiaceae, Reevesia and Ginkgo indicates that the temperature was relatively higher in the time of formation of Seyitömer samples. The presence of Cedrus in large amounts in Seyitömer and lesser amounts in Pelitçik samples may result from latitudinal difference within Anatolia.

Ivanov et al.’s [14] study showed that vegetation of the Middle and Upper Badenian (15–13 Ma) of Forecarpathian basin (central Paratethys, NW Bulgaria) was characterized by regular occurrence and abundance of thermophilous species whereas during Sarmatian, subtropical elements like Engelhardia, Reevesia, Itea, Castanopsis, Symplocaceae, Arecaceae tend to decrease and temperate elements such as Alnus, Carpinus, Betula, Corylus, Fagus have an increasing trend. A similar vegetation change is observed in the Sarmatian of other areas of the eastern and central Paratehys ([14] and references therein). The vegetation of Pelitçik Basin, with almost no thermophilous species, can be correlated with Sarmatian vegetation of Forecarpathian Basin. During Sarmatian favourable conditions existed in the Forecarpathian Basin for the development of mixed mesophytic forests characterized by predominance of warm-temperate and subtropical elements together with many paleotropical elements. However, the temperature was not high enough in the Pelitçik Basin for the presence of numerous tropical and subtropical species within mixed mesophytic forests.

The consistent occurrence of terrestrial palynomorphs and freshwater algae in all of the studied samples may indicate a lacustrine environment. This interpretation agrees with mineralogical data from the studied area [33]. The presence of freshwater algae such as Ovoidites and Spirogyra, at the base of Zone 2, together with pollen derived from aquatic plants such as Sparganium and Potamogeton indicates the occurrence of freshwater ponds [28]. Ferns (Polypodiaceae) grew on the moist soil enclosing the sites of open water and also as understory of mixed mesophytic forests.

The highest relative abundance of Chenopodiaceae (40%) was found close to base of Zone 2 accompanied by peaks of Sparganium and Poaceae (Fig. 3). Chenopodiaceae grew on sandbanks and sandy soils located between lakeshore vegetation and swamp forest [9]. Although today Chenopodiaceae are common in dry and saline habitats [17], high amounts of Chenopodiaceae in Pelitçik samples do not indicate dry conditions. The high amount of Chenopodiaceae in the pollen record can possibly be related to edaphic conditions.

Mixed mesophytic forests dominated the vegetation in moderately wet areas further inland. The most abundant taxa in the mesophytic assemblage, besides Pinaceae, are Ulmus, Carpinus orientalis, Carya and deciduous Quercus. A high frequency of Pinaceae indicates close proximity of highlands to the depositional area since conifers usually prefer to live on highlands. Today, Pelitçik Basin represents a topographically low area bounded by high volcanic terrain.

Although the relative abundance of taxa varies, in general, all four palynological associations namely swamp forest, mixed mesophytic forest, terrestrial herbs and aquatic plants show a decreasing upward trend in Zone 2 (Fig. 3). This trend is coincident with the vegetational signal of climatic deterioration. Nagy [28] established paleoclimatic zones of the Hungarian Neogene and reported a Middle Sarmatian (12.85–12.4 My) cooling phase (Zone VI) with a considerable decrease in number of tropical species and appearance of new subtropical and temperate species. Jimenez-Moreno [16] observed the vegetation changes from the late Early Miocene (Late Burdigalian-Langhian) to the late Middle Miocene (Serravalian) in central Europe (Pannonian Basin, Hungary) and stated that, thermophilous elements dominated vegetation was progressively substituted by deciduous and mesothermic plants. The author related this vegetation change to climatic cooling. Chamley et al. [8] point to a worldwide Middle Miocene cooling reflected by changes in planktonic foraminiferal associations, clay minerals and stable isotopes of Sicily, between 15–13 Ma. This Middle Miocene cooling may probably account for decreasing upward trend of palynomorphs in the Zone 2 of Pelitçik basin. The presence of Sapotaceae, Engelhardia and Cyrillaceae at lower parts and Picea at upper parts of Zone 2 supports this interpretation.

During the early Middle Miocene, climatic conditions favoured the accumulation of terrestrial organic materials into lacustrine and swamp environments in central Europe and Turkey [10], [11], [23], [25], [26], [30], [34] and [43]. In these areas, Taxodium swamp forests produced thick coal layers, whereas in the Pelitçik sequence coal is not present, and swamp forest association is mainly represented by riparian plants. This implies that conditions were not favourable to swamp forests. The Pelitçik palynomorph assemblage reflects slightly cooler climatic conditions compared with other early Middle Miocene floras. This is possibly related to intense volcanic activity in the area.