Tectono-sedimentary evolution of an Early Pleistocene shallow marine fan-deltaic succession at the western coast of Turkey

Abstract

The Quaternary period on the western coast of Turkey is studied using sedimentological features and geochronological age data of the Söke-Milet Basin (SMB), which is a subsidiary to the Büyük Menderes Graben (BMG). Here, for the first time, we geochronologically document the Early Pleistocene shallow marine fan-deltaic succession in the Fevzipaşa Formation (basin-fill unit of the SMB), 15 km inland of the current Aegean coast and 150 m above current sea level. The formation outcrops at the western end of the BMG. It comprises an alluvial fan to freshwater carbonate, shallow marine fan-deltaic and alluvial fan depositional packages separated by intrabasinal unconformities. Based on conventional sedimentary data, seven different facies associations (FA) have been distinguished in the Fevzipaşa Formation: (FA 1) hyperconcentrated flow-generated lower alluvial fan deposits, (FA 2) freshwater lacustrine carbonate deposits, (FA 3) prodelta deposits, (FA 4) shallow marine fan-delta slope deposits, (FA 5) nearshore sandy mouth-bar-type fan-delta front deposits, (FA 6) alluvial fan-delta top deposits and (FA 7) hyperconcentrated flow-generated upper alluvial fan deposits. The shallow marine facies above the lower alluvial fan deposits, considered in conjunction with stratigraphical observations and geochronological and paleontological age data, suggest that a late Early Pleistocene transgression affected the Aegean region.

Keywords:

• Pleistocene
• marine fan-delta
• facies analysis
• Büyük Menderes Graben
• western Anatolia

1. Introduction

Global and local relative sea-level changes (due to eustatic changes, compaction, or tectonic subsidence and uplift) exert considerable control over marine environments (Bowen & Gibbard, 2007; Murray-Wallace, 2002; Papanikolaou et al., 2011) and even continental settings (those that are marine connected, such as the western Anatolian Grabens). The continental shelves of the western Anatolian Grabens comprise Late Pleistocene river delta successions that prograded from rivers flowing in the E–W-trending active grabens of western Turkey, for example, the Büyük Menderes Graben (BMG) and the Küçük Menderes Graben (Aksu, Konuk, Uluğ, Duman, & Piper, 1990; Aksu & Piper 1983; Aksu, Piper, & Konuk, 1987a, 1987b; Ergin, Kadir, Keskin, Turhan-Akyüz, & Yaşar, 2007; Gökçen, Kazancı, Yaşar, Gökçen, & Bayhan, 1990; Piper & Perissoratis, 1991; Rojay, Toprak, Demirci & Süzen, 2005; Uluğ, Duman, Ersoy, Erdeniz, & Avcı, 2005). The present morphology of the Aegean coast of Turkey was formed synchronously with the latest delta formation (Erinç, 1978; Erol, 1976; Hakyemez, Erkal & Göktaş, 1999; Göney, 1975; Kayan, 1996).

Despite several studies concerning the geoarchaeology and limited interpretations of subsurface data based on marine incursions into the BMG, field-based sedimentary data related to the Quaternary marine successions have not been reported except for the following few studies. Nebert (1955) first described the marine Pliocene Cardium sands from the Söke area. Then, Ternek (1959) identified marine fossils from drill cores of the basin-fill deposits of the Söke-Milet Basin (SMB). Becker-Platen and Löhnert (1972) found and identified the marine mollusk Cardium edule from mudstone outcrops in two localities near Söke. Following a comparison of sapropel content of the eastern Mediterranean area, Aksu et al. (1987b) suggested that the initiation of the Büyük Menderes Delta Complex occurred in the Late Pleistocene age. Aksu et al. (1990) developed this idea and represented four sequential levels of the Büyük Menderes offshore delta complex using seismic data, isotopic stages, C¹⁴ ages and benthic δ¹⁸O records. There are also geoarchaeological studies referring to marine incursions, for example, Brückner (1997), Müllenhoff, Handl, Knipping and Brückner (2004) and Brückner, Müllenhoff, Handl, Marburg, and Van der Borg (2002). These works studied the Holocene evolution of the Büyük Menderes Delta using shallow corings in the alluvial and delta plain and found that the Holocene (6000–5000 yr BP) shoreline of the eastern Aegean Sea shifted by more than 50 km inland along the BMG. Kazancı, Dündar, Alçiçek and Gürbüz (2009) applied the principles of sequence stratigraphy to the Holocene succession of the BMG and using boreholes and geophysical data; they interpreted possible marine transgressions. However, field-based geological data of the Pleistocene marine effects have not been reported yet. The aims of this paper are to present the first lithostratigraphic and sedimentological descriptions of the newly discovered Early Pleistocene shallow marine fan-deltaic succession in the northwestern margin of the SMB and to describe the Quaternary geological evolution of the area with respect to the relative sea-level changes that have affected the Aegean region.

2. Stratigraphy

The Plio–Quaternary SMB, a western branch of the E–W-trending BMG, is a large NE–SW-trending active depression in western Anatolia (Figure 1). To propound the stratigraphic sequence of the basin and to simplify the tectonic history of the region, the rock units exposed in the area are investigated in three groups: (1) basement rocks, (2) Miocene Söke basin-fill units and (3) post-Miocene SMB-fill units (Figure 2).

Figure 1. Generalized geological map of the western part of the BMG showing the crystalline basement rocks, Neogene volcano-sedimentary rocks and recent basin floor deposits (modified and simplified after 1/500000 scale geological map Denizli sheet published by Mineral Research and Exploration Directorate of Turkey, Konak & Şenel, 2002 and compiled from Okay, 2001 and Candan et al., 2011). The study area is indicated.

Figure 2. Neogene to Quaternary stratigraphy of the SMB (documented age and paleontological data were derived from studies compiled by Sümer, İnci & Sözbilir, 2013).

2.1. Basement rocks

The basement rocks comprise pre-Miocene metamorphic and non-metamorphic rock units. The pre-Miocene basement rocks considered here consist of three units: the Menderes Metamorphic Massif, the Mesozoic Cycladic Metamorphic Massif and the Lycian Nappes, which belong to the Tauride-Anatolide block. The Menderes Massif consists of gneiss, mica schist, phyllite, marble, metaquartzite and metasandstone cropping out mostly at the southeastern margin of the SMB. The Cycladic Metamorphic Massif overthrusts the Menderes Massif and comprises high-pressure, low-temperature Eocene blueschist metamorphic rocks composed mainly of mica schists intercalated with calc-schists, marbles, thinly bedded cherts and lenses of mafic metavolcanic rocks (Candan, Dora, Oberhänsli, Oelsner, & Durr, 1997; Çetinkaplan, 2002; Gessner, Ring & Güngör, 2011; Oberhänsli, Monie & Candan, 1998; Okay, 2001; Ring et al., 2007). The Lycian Nappes crop out mainly on the east side of the Samsun Mountain and rest structurally above blueschist units (Candan et al., 2011; Rimmelé, Oberhänsli, Candan, Goffé, & Jolivet, 2006). The Lycian Nappes are found as tectonic slices marked by typical red-green phyllites at the base and by grayish and yellowish limestones, dolomites and recrystallized limestone toward the top (Güngör & Erdoğan, 2001; Rimmelé et al., 2006). The Nappes are also defined by Çakmakoğlu (2007) as Kayaköy Dolomite, comprising gray, light/dark gray or whitish-gray colored, thick-bedded, medium-fine crystalline, locally melted porous recrystallized limestones and dolomites.

2.2. Miocene Söke basin-fill units

Miocene continental units deposited in the Söke basin are represented by two sequences bounded by unconformities (Figure 2). The older sequence consists of an alluvial fan to lacustrine sediments including mineable coal levels. The unconformably overlying younger sequence comprises coarse clastics at the bottom, grading upwards into lacustrine carbonates. These are cut by Hisartepe volcanics, which are dated to 12.31 ± 0.09 Ma (Sümer, İnci & Sözbilir, 2013). A detailed description of the Miocene successions is beyond the scope of this paper, and readers are referred to Sümer et al. (2013) for further information.

2.3. Post-Miocene SMB-fill units

The SMB-fill units consist of two principal sedimentary successions: (1) the older Upper Pliocene–Pleistocene alluvial fan to lacustrine, shallow marine fan-deltaic and alluvial fan deposits belonging to the Fevzipaşa Formation and (2) the younger Holocene alluvial fan and alluvial plain deposits, laterally interfingering with channel/floodplain and marine deltaic successions, which here are called modern basin-fill deposits (Figure 2).

2.3.1. Fevzipaşa Formation

The Fevzipaşa Formation is composed of three depositional packages separated by two intraformational unconformities: (1) coarse to fine clastics and limestone lenses covered with an ash-fall (LASH) layer, (2) sand-dominated coarse to fine clastics in the middle section and (3) conglomerate-dominated coarse to fine clastic sedimentary deposits, including a second ash-fall (UASH) layer, at the bottom (Figure 2). Detailed sedimentological descriptions of the depositional packages are given in section 4.

The Fevzipaşa Formation rests unconformably on the Miocene SMB-fill units. The basal part of the formation is characterized by polygenetic conglomerates, which are gray massive to crude horizontally bedded and poorly sorted with medium consolidation. The granule- to cobble-sized clasts are generally subangular and composed predominantly of marble, metaquartzite, schist, metabasics, phyllite and minor amounts of ultramafic rocks. Some conglomerate beds are represented as massive- to thick-bedded, ungraded, poorly sorted, middle to coarse sand matrix-supported and some parts have clast-rich texture. The interfingering carbonate lenses consist of micritic and algal laminated limestone, including some bioclasts such as gastropods, mollusks and ostracods. They are massive to thick bedded and locally silicified. The middle parts of the formation consist of grayish beige to brownish, very fine- to coarse-grained, micaceous, well-sorted, poorly consolidated, massive- to thin-bedded and cross-stratified sandstones. The mudstones laterally interfingering with the sandstones are green to light gray, thick-bedded and poorly consolidated, containing ostracod shells, planktonic diatoms and plant detritus. The upper part of the formation is represented by an alternation of massive- to thick-bedded conglomerates and gravely sandstones intercalated with the ash-fall layer at the bottom. The lower ash coincides with the boundary between the lower and middle parts of the Fevzipaşa Formation, and the upper ash found between the middle and upper parts of the formation. These are whitish beige, fine-grained, pumice and biotite-bearing layers, which are 0.16 and 0.20 m thick, respectively.

The Fevzipaşa Formation was dated by Ünay, Göktaş, Hakyemez, Avşar, and Şan (1995) and Ünay and Göktaş (1999) based on the identification of a number of micro mammalian fossils: Kalymnomys (Tibericola) aff. Jordanica, Apodemus mystacinus, Apodemus sylvaticus/A.flavicollis, Arvicola sp., Microtus sp. and Soricidae sp., which indicated late Early Pleistocene (Biharian) age. Sarıca (2000) also found similar fossil assemblages in the formation, such as Kalymnomys mojor, Mimomys cf. Ostramosensis and Apodemus cf. flavicollis, which yielded Late Pliocene–Early Pleistocene age.

In addition to the paleontological data, we collected four samples from the LASH and UASH layers for radiometric age determination (Figure 2). The determinations of radiogenic argon content were carried out twice using an MI-1201 IG mass spectrometer via the isotope dilution method with ³⁸Ar as spike. The potassium contents were determined twice using the flame spectrophotometry method. For age calculations, international values of constants were used as follows: λ_K = 0.581 × 10⁻¹⁰ y⁻¹, λ_β– = 4.962 × 10⁻¹⁰ y⁻¹ and ⁴⁰ K = 0.01167 (at.%). The LASH layer yielded a K/Ar age of 2.4–2.25 Ma, and the UASH layer yielded an age of 0.95–1.18 Ma (Table 1). The above radiometric and paleontological age data reveal that the Fevzipaşa Formation is Late Pliocene–Pleistocene in age.

Table 1. Radiometric K/Ar age data of the Fevzipaşa Formation. Apparent age spectra, including results of isotopic-geochronological data of ash layers (LASH and UASH).

Lab no.	Layer	Sample no.	Analysed material	K, % ± σ	^40Arrad (ng/g) ± σ	^40Aratm (%) in smple	Age ± 2σ (Ma)
15153	UASH	B-02 M	Matrix	1.96 ± 0.02	0.161 ± 0.009	95.6	1.18 ± 0.13
15159		B-02B	Biotite concentrate	2.61 ± 0.03	0.173 ± 0.013	96.8	0.95 ± 0.15
15152	LASH	K-01 M	Matrix	2.65 ± 0.03	0.417 ± 0.012	74.0	2.25 ± 0.15
15158		K-01B	Biotite concentrate	1.47 ± 0.02	0.243 ± 0.018	96.3	2.4 ± 0.3

Notes: UASH (Upper ash-fall layer), LASH (Lower ash-fall layer).

2.3.2. Modern basin-fill deposits

The modern basin-fill deposits consist of two major depositional facies: (1) coarse-grained lateral marginal alluvial fan deposits and (2) fine- to coarse-grained axial fluvial deposits interfingered with alluvial plain deposits and deltaic deposits of the Büyük Menderes River (BMR).

The marginal alluvial fan deposit is exposed as a few small to large isolated outcrops in faulted contact with the crystalline basement rocks at the northwestern margin of the SMB. A lateral equivalent of these fan deposits is interfingered laterally and vertically with river-deltaic deposits of the BMR and alluvial plain deposits in the modern basin (Figure 2). At the western end of the basin, these deposits are associated with a complex variety of lagoons, natural levees, inlets, fine-grained sand beaches, river promontories, sand bars and other transitional sedimentary facies of the present Aegean coast. These river-deltaic deposits comprise the largest delta complex in Western Anatolia, encompassing an area of up to 200 km² (Figure 1).

3. The basin boundary faults

The SMB has been shaped by successive deformations controlled by the Yamaçköy and Priene-Sazlı Faults (PSF).

3.1. Yamaçköy fault

The Yamaçköy Fault is an approximately 5.5 km long, NE-trending and SE-facing range-front fault. It is located southwest of Yamaçköy village, striking between the village to the NE and the Hisartepe Hill to the SW, where it runs along the southern flank of the Göldağ Mountain (Figure 3). The footwall rocks of the Yamaçköy Fault consist mainly of marble, recrystallized limestone, metasediments, ophiolitic rocks belonging to the crystalline basement and Miocene continental units, while the hanging wall rocks are represented by thick deposits of the Fevzipaşa Formation. In front of the fault, blocky and coarse-grained-dominated successions of the upper alluvial fan deposits are exposed (see section of facies associations) with thicknesses extending up to 250 m. These suggest that the Yamaçköy Fault controlled the deposition of the Fevzipaşa Formation. The fault has dip angles ranging between 64°S and 85°SE. Several kinematic indicators and fault structures, such as corrugations, slickenlines, chatter marks, extensional cracks and fault breccias, have been observed, which reveal that the fault shows high-angle oblique-slip normal fault characteristics formed under a NW–SE extension (for further details, see Sümer et al. (2013)).

Figure 3. Detailed geological map of the Söke area and surroundings (see Figure 1 for location of the map).

3.2. Priene-Sazlı fault

The PSF is the most striking structural element within the study area, and it has been studied and identified previously by numerous researchers (Altunel, 1998; Gürer et al., 2009; Gürer, Bozcu, Yılmaz & Yılmaz, 2001; Hancock & Barka, 1987; McKenzie, 1972, 1978; Nebert, 1955; Öcal, 1958; Phillipson, 1911; Roberts, 1988; Sümer, İnci & Sözbilir, 2008; Sümer et al., 2013; Yönlü, Altunel, Karabacak, Akyüz, & Yalçıner, 2010). The fault forms the northern margin of the modern SMB (Figure 1). According to Sümer et al. (2013), the total length of the fault is approximately 40 km and in some parts, the width of the fault zone extends to 350 m. The PSF can be followed toward the north as a NE–SW-trending structure stretching from Söke to Argavlı. About 28 km toward the southwest of Söke, the fault turns westward near Atburgazı, assumes an E–W direction after Doğanbey and trends approximately 9 km to the west of Karina. The E–W-trending parts of the fault delineate the southern limit of the Dilek Peninsula (Figure 1). The fault determines the tectonic boundary between the older pre-Miocene basement and the modern basin-fill deposits. According to Sümer et al. (2013), the PSF is a reactivated structure, which is evidenced by three distinct slickenlines on the same fault surface. The former strike-slip slickenlines are overprinted by dip-slip slickenlines. The present PSF is an active high-angle and dip-slip fault with concave, curvilinear geometry, which shows a general NE trend and SE face to the north and an E–W-trending and S-facing range-front to the south. Moreover, the 1955 earthquake (M_S = 6.8) occurring on this fault zone was reported by numerous researchers (Altunel, 1998; Duman, Emre, Özalp & Elmacı, 2011; Gürer et al. 2001; Eyidoğan & Jackson, 1985; Şengör, 1987; Yönlü et al., 2010). Thus, the PSF still controls and plays an active role on progressive deformation of the SMB.

4. Facies associations of the late Pliocene–Pleistocene Fevzipaşa Formation

The Fevzipaşa Formation is divided into three depositional packages that are separated by two intraformational unconformities: (1) alluvial fan to freshwater lacustrine carbonate deposits (FA 1 and FA 2), (2) shallow marine fan-deltaic deposits (FA 3, FA 4, FA 5 and FA 6) and (3) alluvial fan deposits (FA 7). Representative sedimentary logs and correlations of these deposits are shown in Figures 4 and 5. In our work, we have distinguished 23 facies and 7 facies associations (FA) based on lithology, grain size and boundary condition, texture and internal sedimentary structures within the Fevzipaşa Formation. These facies and FA are summarized in Tables 2 and 3, respectively. Key observations and interpretations are provided below.

Figure 4. Measured reference stratigraphic sections with descriptive facies assemblages of the Fevzipaşa Formation (see Figure 3 for locations and Tables

Table 2. Descriptions and interpretations of sedimentary lithofacies of the Fevzipaşa Formation.

Facies		Main descriptive sedimentary features	Interpretation
G	Gm, Massive conglomerate	Massive, ungraded, poorly sorted, sand matrix-supported, erosive lower boundary	Clast-rich fluidized debris flows
	Gms, Horizontally stratified conglomerate	Thick (>0.80 m), sand matrix -supported, poorly sorted, coarse-grained sandstone intercalates, normal or normal to inverse-graded, slightly erosive lower boundary, transitional or abrupt boundary with gravelly sandstones, rare paleocurrent fabric	Cohesionless debris flows; hyperconcentrated flows
	Gmc, Clast-rich crudely stratified conglomerate	Thick (>1 m), poor sorted, sand matrix-supported or clast-supported, abrupt or transitional boundary with gravelly sandstones, random normal grading, slightly erosive lower boundary, rare paleocurrent fabric	Clast-rich flows; hyperconcentrated flows
	Gp, Low-angle cross-stratified conglomerate	0.5–1 m in thickness, granule to pebble clast-supported, moderate-sorted, gently erosive lower boundary, laterally and vertically transition with gravelly or massive sandstones, laterally continuous up 30–40 m	Channelized hyperconcentrated flows; channelized subaqueous flows
	Gmin, Inversely and normal-graded conglomerate	Thick (>1.50 m), poor-sported, sharp and gently undulating lower boundary, clast orientation parallel to upper stratification plane	Cohesive and cohesionless debris flows; hyperconcentrated flows
	Ch, Channel-fill conglomerate and sandstone	Pebble to cobble-size gravelly lag deposits, horizontally and low-angle cross-stratified conglomerates with sandy matrix and massive sandstones in incised (3–4 m deep and 10−15 m width) channels, deep erosive lower boundary	Subaerial and subaqueous channelization or incision and resedimentation; mouth bar incision by overflows of bar surface
S	Smg, Gravelly sandstone	Massive or crudely stratified, poor consolidated, coarse-grained, scattered gravels and thin conglomerate intercalates, poor-sorted, partly graded, abundant micaceous, alternation with massive sandstones, random load casts	Rapid deposition and suspension from hyperconcentrated flows, subaerial and/or land subaqueous sediment-laden gravity currents
	Smp, Pebbly sandstone	Massive, coarse-grained, well-rounded marble pebbles in sand matrix	Subaerial or subaqueous sediment gravity flows or currents and abrupt sediment discharges
	Sm, Massive to thick-bedded sandstone	Variable in thickness (50 cm–5 m), granule pockets and trials, moderately sorted, fine to coarse–grained, graded, poor-consolidated, abundant micaceous, transition with gravelly sandstones and laminated sandstones, mollusks of Cardium (Cerastoderma) edule Didacna sp.	Rapid deposition and suspension from hyperconcentrated flows, subaerial and/or land subaqueous sediment-laden flows
	Smc, Pebbly-carbonate sandstone	Massive, carbonate cemented, rounded and scattered fine marble pebbles, coarse sand grained supported	Reworked detrital grains with currents, carbonate precipitation, mixed carbonate-siliciclastic deposition.
	Sp, Planar cross-stratified sandstone	Variable in thickness (1–6 m), mixed coarse–grained sand and granule, 25°–30° dipped cross-sets, clast-supported non-erosive or slightly erosive lower boundary with laminated sandstone; rare incised channels	Sand bar deposition by transitional or lower flow regime; progradational deposition
	Sw, Wavy and low-angle laminated sandstone	Fine to medium-grained, gentle wavy and low-angle lamination, moderately sorted, micaceous, water escape structures	Reworking and redeposition by oscillatory waves
	Sl, Plane parallel laminated sandstone	Fine to medium-grained, well-sorted, micaceous, soft sedimentary drapings, water escape structures, rare bioturbation	High or low density current flows; wavy traction
	Src, Current ripple cross-laminated sandstone	Fine to medium-grained, well-sorted, asymmetric, micaceous beds of 2–10 cm thick	Migrating currents; reworking and redeposition by currents
	Srw, Wave ripple cross-laminated sandstone	Fine to medium-grained, well-sorted, symmetric, micaceous beds of a few cm thick	Migrating waves; reworking and redeposition by waves
	Shcs, Hummocky cross-stratified sandstone	Very fine to fine-grained, well sorted, low-angle cross-lamination, minor wavy lamination	Reworking and deposition by storm-generated, and/or oscillatory flows
F	Fm, Massive-to thick-bedded mudstone	No grading, brackish and marine ostracods (Tyrrhenocythere amnicola, Candona paralella pannonica), planktonic diatoms (Actinocyclus normanii, Cyclotella distinguenda, Cyclotella glabriuscula, Cyclotella kuetzingiana, Stephanodiscus niagarae), sideritic nodules, less plant debris	Subaqueous rapid suspension; fallout deposition
	Fl, Laminated mudstone	1–5 mm plane lamination, no grading	Deposition by subaqueous traction and/or low-density subaqueous currents
C	Cs, Stratified carbonate	Thin to thick-bedded, micritic, freshwater mollusks, algal stems, rare isolated serpantinite and marble clasts.	Carbonate precipitation or suspension and biogenic carbonate deposition
	Css, Sandy carbonate	Thin to thick-bedded, lateral and vertical transition with Cs and conglomerate facies	Carbonate precipitation dominant mixed carbonate-siliciclastic deposition.
	Cg, Gastropods carbonate	Massive, thick-bedded, planispiral freshwater gastropods, locally silicified, well-compacted	Low-energy matrix-rich bioclastic carbonate deposition
V	Va, Volcanic ash	Whitish beige, fine-grained, single beds in 14–20 cm, pumice clasts and biotite rich volcanic ash	Ash fall deposition from explosive volcanism during lower and upper alluvial sedimentations
P	P, Paleosol	Brownish mottling, irregular carbonate concretions in dark greenish claystone	Quiescent stage in alluvial sedimentation

2 and

Table 3. Descriptions and interpretations of FAs of the Fevzipaşa Formation.

	Sedimentary features	Depositional settings and environments
FA 1, Lower alluvial fan deposits	Smg, Sm, Gms dominant; Gmcs, Gp, Sl accessory; common reddish oxidation; common erosional surfaces; fining upward; abundant micaceous; poor consolidation; lateral interfingering with freshwater carbonate deposits; Paleosol formation	Hyperconcentrated flow dominated alluvial fans
FA 2, Freshwater lacustrine carbonate deposits	Cs and Cg dominant; lateral interfingering with Smc, Cs and Css facies; common freshwater mollusks and ostracods; algal lamination	Freshwater lake and lake margin carbonate deposition
FA 3, Prodelta deposits	Alternation of Fm and Fl; brackish to marine ostracods; planktonic diatoms	Subaqueous low-concentrated sediment gravity and suspension in prodelta part below wave base in distal parts of the fan-delta slope; marine offshore transition zone
FA 4, Shallow marine fan-delta slope deposits	Sm, Sw, Sl, Smp dominant; less Srw, Sr, Shcs and Gp; erosional disconformity surfaces; brackish to marine mollusks of Cardium (cerastoderma) edule and Didacna sp.; bioturbation	Subaqueous sediment-gravity and wave/current- induced deposition in a low-angle delta slope environment; marine lower shoreface depositional conditions
FA 5, Nearshore sandy mouth bar-type fan-delta front deposits	Sp, Sl, Srw, Sr dominant; less Sm; lob-shaped geometry, non-erosive or sharp lower boundary; 1–10 m thick, lateral continuous more than 30–40 m; incision on bar surface	Subaqueous spreading of hyperconcentrated flows on a very low-angle <1° depositional slope, mouth bar-type shallow marine fan delta front environment; marine foreshore and upper shoreface depositional conditions
FA 6, Alluvial fan-delta top deposits	Gp, Gmin, Smg dominant; Gm, Gmc accessory; common erosional and sharp surfaces; irregular coarsening and fining upward; micaceous; poor-consolidation	Gravity and hyperconcentrated flow dominated alluvial fans, subaerial fan-delta top
FA 7, Upper alluvial fan deposits	Smg, Sm, Gm dominant; Gms, Sl accessory; common erosional surfaces; irregular mostly fining and coarsening upward; abundant micaceous; poor-consolidation and reddening	Hyperconcentrated flow dominated coalesced alluvial fans

3 for explanation of lithofacies and FAs).

Figure 5. Laterally correlated reference stratigraphic sections with descriptive facies assemblages of the Fevzipaşa Formation (see Figure 3 for locations and Tables 2 and 3 for explanation of lithofacies and FAs).

4.1. FA 1: lower alluvial fan deposits

The Upper Pliocene lower alluvial fan deposits overlie the Miocene continental non-marine rock units unconformably (Figure 2 and log 2 of Figures 4 and 5). The dominant clastic facies components of FA 1 are gravelly sandstone, massive- to thick-bedded sandstone and massive, horizontally stratified and clast-rich crudely stratified conglomerates (Smg, Sm, Gm, Gms and Gmc) (Figure 6(A) and (B)). FA 1 are separated stratigraphically from the prodelta deposits (FA 3) by an intrabasinal unconformity and overlain by upper alluvial fan deposits (FA 7) with a younger intrabasinal unconformity. The conglomerate- and sandstone-dominated facies of FA 1 interfinger with the carbonate facies of FA 2 (Figures 2, 4, 5 and 6(C)). In addition, the upper part of FA 1 includes an approximately 16-cm-thick LASH layer (Figure 6(D)).

Figure 6. Photographs of representative facies showing lower part of the Fevzipaşa Formation. (A and B) The conglomerate and sandstone facies of FA 1, (C) the lower alluvial fan deposits (FA 1) and freshwater carbonate deposits (FA 2), (D) lower ash-fall layer (LASH) south of Burçaktepe (Figure 3 and log 2 of Figures 4 and 5), (E) Smc, Css, Cs and Cg facies alternation in freshwater carbonate deposits (FA 2) in Löngez stream section (Figures 3 and 5, log 7).

4.2. FA 2: freshwater carbonate deposits

FA 2 are represented by pebbly carbonate sandstone, stratified carbonate, sandy carbonate and gastropods carbonate facies (Smc, Cs, Css and Cg) (Tables 2, 3 and Figures 2, 4, 5 and 6(E)). Stratified carbonate facies (Cs) are predominantly micritic and algal laminated in nature (Figure 7(A)). In addition, Charophyta algae are found in abundance (Figure 7(B)). Common bioclasts are derived from gastropods, mollusks and ostracod shell fragments. The gastropods carbonate facies (Cg) are massive, thick bedded, locally silicified and well compacted. Planispiral freshwater gastropods are also common (Figure 7(C)). Sedimentological and paleontological evidence indicates a fresh water carbonate deposition in a lacustrine environment. The facies features of the Smc, Cs and Css indicate deposition in shallow, fresh, small carbonate lake(s) and carbonate lake-margin-front environments ponded in distal parts of the alluvial fans. Massive, thick-bedded, locally silicified, well-compacted Cg may represent deeper parts of the lacustrine environments.

Figure 7. (A and B) Thin-section photograph of stratified carbonate facies (Cs), (A) indicating micritic composition and algal lamination (between red arrows), (B) Charophyta algae, (C) Planispiral freshwater gastropod in Cg facies. (D) Field photograph of the molluscan shells and fragments. (E) Cardium (Cerastoderma) edule Linné, (F) Didacna sp., (H) Proboscidea indet. in gravelly sandstones facies (Smg) at Burçaktepe locality.

4.3. FA 3: prodelta deposits

FA 3 are represented by an alternation of massive- to thick-bedded mudstone and laminated mudstone (Fm and Fl) facies (Tables 2 and 3, Figure 8(A)). The mudstones of this FA transitionally underlie the sandstones of FA 4 and overlie the conglomerates and sandstones of FA 1 (Figure 8(B)). The brackish-water and marine ostracods of Tyrrhenocythere amnicola and Candona paralella pannonica and freshwater to marine planktonic diatoms, such as Actinocyclus normanii Hustedt, Cyclotella distinguenda Hustedt, Cyclotella glabriuscula, Cyclotella kuetzingiana and Stephanodiscus niagarae Ehrenberg, are common within FA 3. The Fm and Fl facies together may indicate deposition by subaqueous low-density flow currents and traction sedimentation (e.g. Ghibaudo, 1992; Reading & Collison, 1996).

Figure 8. Photographs of representative facies showing upper part of the Fevzipaşa Formation. (A) Fm, Fl dominated prodelta deposits (FA 3) are overlain by sandstones of FA 4. (B) Prodelta mudstones overlie the deposits of FA 1. (C, D, E) Shallow marine fan-delta slope deposits (FA 4). Note the hummocky cross-laminations in photo E. (F) The facies of FA 5. Note the laterally discontinuous light colored small-scale scour and fill sandstones terminated by current ripple cross-laminated sandstones (Src).

4.4. FA 4: shallow marine fan-delta slope deposits

Coarse- to fine-grained micaceous sandstones are dominant in this unit (Tables 2 and 3), comprising ~50% of all the marine sediments within the measured sections. Sediments ascribed to the shallow marine fan-delta slope environment are the marine-influenced basin-ward equivalents of FA 5. Erosional discontinuity surfaces, normal and inverse grading, and lamination are common sedimentary structures in FA 4 (Figure 8(C) and (D)). In the absence of trace fossil facies molluskan shells and fragments slightly observed (Figure 7(D)), our interpretation as shallow marine fan-delta slope deposits is based on the interfingering with deposits of FA 5, the presence of marine indicators, such as marine/brackish-water mollusks of Cardium (Cerastoderma) edule Linné, Didacna sp. (Figure 7(E) and (F), wave-generated hummocky and wavy-type cross-strata (Figure 8(E)), bioturbations and bidirectional paleocurrents. These mollusks can be correlated with the same mollusks observed in the Pleistocene (Bakunian) beds of the marine Hamzakoy Formation in the Gelibolu Peninsula (Taner, 1983). The Holocene brackish-to-marine mollusk Cerastoderma edule has also been reported from sediments of the brackish residual Lake Bafa in the Büyük Menderes valley (Müllenhof et al. 2004).

The sedimentary facies features given above indicate the deposition of low-density gravity flows, wave- or storm-generated oscillatory flows and reworking in conditions of a shallow marine environmental (e.g. Elliot, 1986; Hampson & Howel, 2005; Reading & Collison, 1996; Walker & Plint, 1992). Low-angle erosive facies discontinuities, upward-coarsening trends, alternation of both flood- and wave-generated stratification, deposition of subaqueous unconfined pebbly sandstone and low-angle cross-stratified sandy conglomerates (Figures 4 and 5), the faunal content and the entire sedimentary structure architecture may be attributed to a low-angle shallow marine fan-delta slope and/or marine shoreface depositional environments.

4.5. FA 5: nearshore sandy mouth-bar-type fan-delta front deposits

The dominant sandy clastic facies components of FA 5 are planar cross-stratified sandstones (Sp), current and wave ripple cross-laminated sandstones (Src, Srw), plane parallel laminated sandstones (Sl), less massive- to thick-bedded sandstones (Sm) and low-angle cross-stratified conglomerates (Gp) (Table 2, Figure 8(F)). Sediments ascribed to the nearshore sandy mouth-bar-type fan-delta front deposits are the alluvial and marine-influenced basin-ward equivalents of the distal parts of the alluvial fan-delta top deposits (FA 6) (Figures 4, 5 and 9(A)). Fine- to medium-grained, well-sorted, asymmetric and symmetric micaceous wave and current rippled sandstones (Figure 9(B) and (C)) indicate reworking and redeposition by waves and currents in shallow marine environments. The lobe-shaped sandstones (Figure 9(A)) were probably deposited at the outlets of hyperconcentrated flow-dominated distal alluvial fan distributaries. The channeled/unchanneled sand flows probably originated from hyperconcentrated floods of the alluvial fans. This is where floods enter the sea and sediments are dumped in front of the channel mouth, initiating the growth of sand bars. The sediment accumulation on such bars may continue until the bars are subaerially exposed (subaerial channel-fill deposits in FA 5, Figures 4 and 5). Tractional deposition may be more common toward the upper parts of the mouth bars, and this may cause progradational deposition. The facies features of FA 5 support subaqueous sand bar deposition under transitional and/or conditions of a lower flow regime (Allen, 1982; Collinson, 1996; Miall, 1977, 1978) and sandbar back-reworking by currents or oscillatory waves in the upper flow regime of very shallow water conditions (e.g. Martel & Gibling, 1991; Reading & Collison, 1996). The lateral extension of the mouth-bar deposits and paleocurrent data indicates that the marine coastline had an approximately ENE–WSW orientation.

Figure 9. Photographs of representative facies showing the uppermost part of the Fevzipaşa formation. (A and B) Stratigraphical relationships between FA 6 and FA 5. The conglomerates of FA 6 and FA 7 rest directly on the cross-stratified sandstone of FA 5 (black arrows). (A) Stratigraphical relationships between FA 6, FA 5 and FA 4. Note the erosional base of the conglomerate (arrows) and lobe-shaped depositional pattern of the sandstones. Sp facies changes abruptly into sandstone facies of FA 4, (B) The conglomerate of FA 7 rests unconformably on the coarse-grained Sp facies of FA 5, (C) Current and wavy ripple cross-laminated sandstone (Src and Srw) intercalations in FA 5, (D) Conglomerate and sandstone facies of FA 7 representing proximal parts of the alluvial fan(s). Note the erosional bases, normal grading and transition to gravelly sandstone facies, (E) Gravelly sandstone facies (Smg) dominate the medial-distal parts of the alluvial fan(s). Note the pebble conglomerate lens (arrow) and scattered pebbles in poorly consolidated micaceous sandstone. Persons for scale in all photos are approximately 1.75 m in height, hammer is 30 cm long and pen is 14 cm long.

4.6. FA 6: alluvial fan-delta top deposits

This association consists predominantly of clast-rich crudely stratified conglomerate (Gmc), low-angle cross-stratified conglomerate (Gp), inversely and normally graded conglomerate (Gmin) and gravelly sandstone (Smg) (Figure 9(A)). The boundaries of the facies represent common erosional and sharp surfaces, and internal sedimentary features show irregular coarsening and fining upwards. The low-angle cross-stratification and non-uniform aggradation are thought to reflect at the channeled hyperconcentrated flows and channeled subaqueous flows in distal parts of the subaerial fan-delta top. Furthermore, in this facies, we recently discovered examples of Proboscidea indet. in the Burçaktepe locality (Figure 7(H)).

4.7. FA 7: upper alluvial fan deposits

This FA is attributed to the subaerial sediment dispersion on alluvial fan surfaces. FA 7 consist predominantly of Gm, Gmc and Smg facies (Tables 2 and 3, Figures 4, 5, 9(D) and (E)), and it is much thicker in proximal parts than it is in distal parts; cumulative thickness ranges between 10 and 75 m. The alternated gravelly sandstones (Smg) are commonly massive or crudely stratified, poorly consolidated, coarse-grained, scattered gravels and have thin conglomerate intercalates. The sandstone facies are abundantly micaceous. All included clasts were derived from the Cycladic Metamorphic Complex and the Menderes Massif. The distal parts of the alluvial fan deposit typically overlie the FA 6 deposits in the middle part of the basin; however, in some areas, FA5 are overlain directly by FA 7 with an intrabasinal unconformity (Figure 9(B)). The FA 7 facies features may indicate the occurrence of clast-rich fluidized debris flows and hyperconcentrated flood flows or flash deposition in the proximal to distal parts of these alluvial fans (e.g. Benvenuti, 2003; Blair, 1999a, 1999b; DeCelles et al., 1991; Smith, 1986; Sohn, Rhee & Kim, 1999).

5. The Plio–Quaternary geological evolution of the SMB

The Plio–Quaternary SMB is a superimposed basin formed on the Miocene Söke basin, which was characterized by kinematically linked low-angle normal and strike-slip faults at the western end of the BMG (Sümer et al. 2013). Stratigraphic and sedimentological relations and structural characteristics of the basin-fill deposits reveal that the SMB evolved in five different phases, which are summarized in the following (Figure 10).

Figure 10. The Plio–Quaternary geological evolution of the SMB (see text for facies code and detail, LASH, lower ash-fall deposits; UASH, upper ash-fall deposits; IBUNC, intrabasinal unconformity; ANUNC, angular unconformity).

During the first stage, the Miocene Söke basin was disrupted and broken up by the Yamaçköy Fault to form the northern margin of the SMB during the Late Pliocene. In front of the fault, the lower alluvial fan(s) (FA 1) and fresh water lacustrine carbonate deposits (FA2) were laid down. The final product of the first stage was the LASH deposit, which probably occurred due to an acidic volcanic eruption of the South Aegean Volcanic Province within a radius of approximately 250 km. After the first eruptive volcanic activity, Söke and the surroundings were influenced by the Aegean Sea during the early Early Pleistocene–late Early Pleistocene. This period created the marine incursion and caused the deposition of the shallow marine fan-deltaic sediments (FA 3, FA 4, FA 5 and FA 6) of the Fevzipaşa Formation. During this stage, the alluvial fan-delta top sediments (FA 6) were deposited in a subaerial alluvial fan-delta top environment, while decreasing progressive subsidence provided the deposition of the sand- and fine-grained sedimentary facies (FA 3, FA 4 and FA 5) in a subaqueous fan-delta front environment (Phase 2 in Figure 10). In the late Early Pleistocene (Phase 3), the Yamaçköy Fault caused back-tilting of the hanging wall block under the control of extensional tectonics, and then, alluvial fan deposition dominated the region during the second period of volcanic activity. The UASH layer probably occurred in a similar manner to the LASH layer, following an acidic volcanic eruption of the South Aegean Volcanic Province. At the end of the Late Pleistocene, the northern margin of the SMB was broken up by the NNW–SSE extension of the related high-angle active PSF due to the basin-ward migration of the faults. This final phase led to the formation of numerous alluvial fans of different sizes in front of the PSF, which formed the northern margin of the modern SMB, oriented obliquely to the BMG during the Holocene.

6. Discussion

Despite the absence of the geological record of the Holocene marine sequence in the SMB, global sea-level changes in the eastern Aegean Sea (Flemming, 1972; Flemming et al., 1998; Kayan, 1988; Lambeck, 1995; Lambeck & Chappell, 2001; Perissoratis & Conispoliatis, 2003) and the active tectonics of western Turkey have turned marine incursions or transgressions into the grabens of western Turkey. The Holocene marine beds observed from drill cores in the SMB, which may be related to one of these transgressions, have been discussed by Kazancı et al. (2009). Geoarchaeological studies indicate that during the peak incursion of 6000–5000 yr BP, the Holocene shoreline of the eastern Aegean Sea was shifted by more than 30–65 km inland along the BMG SMB and a marine embayment evolved, which is known as the ‘Latmian Gulf’ (Brückner, 1997; Schröder & Bay, 1996). When the sea level reached its present position in the Holocene, the deltaic sedimentation of the BMR infilled this marine embayment rapidly, the consequence of which was that the historic or prehistoric harbor cities of Priene, Miletos and Myus in the SMB became landlocked (Brückner, 1997; Brückner et al., 2002, 2004; Müllenhoff et al. 2004; Schröder & Bay, 1996). However, the Pleistocene marine effect has not been reported prior to this study, which is based on paleontological, geochronological and sedimentological field data.

The Plio–Quaternary SMB activated as an asymmetric extension-dominated transtensional or oblique extensional basin, probably related to the reactivation of the Miocene structures of the NE-trending supradetachment Söke basin (Sümer et al. 2013). The sedimentation of the Fevzipaşa Formation, along the northwestern margin of the basin, was characterized by an Early Pleistocene shallow marine fan-delta deposit, indicating the transgression of the Aegean Sea into the area.

Most fan deltas that form on the margins of marine or lake systems commonly exhibit nearshore or steep, large-scale delta foresets of Gilbert-type deltas, as has been reported in many studies (e.g. Colella, 1988; Dorsey, Umhoefer & Renne, 1995; Ethridge & Wescott, 1984; Gawthorpe & Colella, 1990; Hwang, Chough, Hong & Choe, 1995; Kleinspehn, Steel, Johansen & Netland, 1984; Leeder, Ord & Collier, 1988; McPherson, Shanmugan & Moiola, 1987; Nemec, 1990; Postma, 1990; Rohais, Eschard & Guillocheau, 2008; Sohn & Son, 2004; Soh, Tanaka & Taira, 1995; Tanaka & Maejima, 1995; Ulicny, 2001; Wescott & Ethridge, 1990; Wood & Ethridge, 1988; Young, Gawthorpe & Sharp, 2000). However, the fan-deltaic succession of the Fevzipaşa Formation generally has much steeper slopes with much shorter delta top to basin distances. The steeper slope may also have triggered substantial slope failures of the foreset deposits. The combination of these factors is likely to have produced poorly developed foresets compared with Gilbert-type deltas. Therefore, the Gilbert-type delta facies are apparently absent in the shallow marine fan-deltaic sequence of the Fevzipaşa Formation. The fining upward non-marine alluvial to carbonate sequence of the Fevzipaşa Formation was subsequently inundated by a marine transgression, which suggests an abrupt tectonic subsidence at the basin margin. The withdrawal of the shoreline from the margin was probably followed by a short-distance progradation of the upper alluvial fans. According to the sedimentary facies analysis, sand and fine sediments were carried by hyperconcentrated flows, which originated from subaerial footwall-sourced coalescing alluvial fans, into standing shallow marine water. Here, they were reworked by waves and currents as nearshore deposits and continued to move down the gentle delta slope under the influence of sediment gravity currents or flows and wave-generated flows. Sedimentation on the coalesced alluvial fans was dominated by confined and/or unconfined hyperconcentrated flood flow processes. The predominantly sand-laden hyperconcentrated flood flows, derived from the alluvial fans, entered the shallow marine waters and subaqueous coarse-grained sandy mouth bars were deposited. The lateral extension of the mouth-bar deposits and paleocurrent data indicates that the marine coastline had an approximately ENE–WSW orientation. Further basin-ward, there was probably a southerly directed shallow marine fan-delta slope dominated by fine-grained sandstones deposited as subaqueous density flows and reworked by waves and current activities. Very fine-grained sands intermittently transported by subaqueous gravity flows into the prodelta region were deposited with the prodelta muds.

There have been several worldwide studies on Pliocene–Pleistocene fan-delta progradation with respect to related sea-level changes. Field & Gardner (1990) defined Pliocene–Pleistocene marine deposits with seismic facies on the east coast of Spain. They specified that the shelf component comprising overlapping and stacked delta lobes and a sequence initiated and controlled by the influx of terrigenous sediment during the Pleistocene indicate a region characterized by a low stand of sea level. Dorsey, Umhoefer and Renne (1995) and Falk and Dorsey (1998) indicated that Gilbert-type fan deltas developed and overlapped non-marine alluvial fans at Lorento basin, Baja California west of the Mexico, between 2.61 and 2.46 Ma (Late Pliocene–Early Pleistocene), which were controlled by repeated variations in fault-slip rates. Furthermore, Stow, Braakenburg and Xenophontos (1995) reported a Pliocene–Pleistocene sedimentary fill representing a fan-delta complex, which shows a broad progradational sequence influenced both by sea-level fluctuation and tectonic activity at Pissouri basin, southwest of Cyprus. Tamura and Masuda (2003) detailed the Plio–Pleistocene marine to fluvial deposits of the northwest Japanese islands. The initial deposition of the fan-delta system may have been preceded by a fall in relative sea level; however, before the deposition of the formation (delta complex with a braided dominated system), the environment was calmer with conditions typical of shelf (e.g. outer) at the end of the Pliocene. Benvenuti (2003) reported that Early Pleistocene sedimentation was characterized by periodic sea-level rises, alternating with periods of alluvial fan progradation and fan-delta development at Mugello basin, on the northwest coast of Italy. Ritchie, Gawthorpe and Hardy (2004) outlined a three-dimensional numerical model of coarse-grained delta deposition and applied it to investigate the response of deltaic depositional systems to different rates and magnitudes of sea-level rise and fall. In addition, there have been many scientific works using benthic and planktonic foraminiferal oxygen isotope records to adapt the global eustatic short-term sea-level changes from the entire Pliocene to Holocene (Abreu & Anderson, 1998; Haq & Al-Qahtani, 2005; Haq, Hardenbol & Vail, 1987; Kominz et al., 2008; Lisiecki & Raymo, 2005; Miller, Fairbanks & Mountain, 1987; Miller et al., 2005; Miller, Mountain, Wright & Browning, 2011; Shackleton, Hall & Pate, 1995; Vail, Mitchum & Thompson III, 1977).

The geochronologically dated shallow marine fan-deltaic succession in the Fevzipaşa Formation (between 2.4 Ma and 0.95 Ma) has also been reported by different workers in different regions: Haq et al. (1987) and Haq and Al-Qahtani (2005) reported a single main sea-level rise; Abreu and Anderson (1998) documented six sea-level rises separated by five sea-level falls; Lisiecki and Raymo (2005) and Miller, et al. (2011) revealed four major sea-level changes rising up to present sea level on their eustatic curves. Thus, during the deposition of the marine fan-deltaic successions of the Fevzipaşa Formation, the region may have been affected by at least one of the sea-level changes mentioned in the literature.

Fan deltas could be developed from a combination of high topography and active tectonics, not only in extensional but also in contractional basins, which could provide substantial amounts of gravity driven coarse clastics for deposition in a stagnant body of water. In the literature, there are two contrasting and acceptable models for fault-controlled extensional basin subsidence and the evolution of a fan-deltaic succession: (1) asymmetric subsidence along a high-angle oblique-slip normal fault showing a listric nature, producing a classic half-graben basin geometry (Umhoefer, Dorsey & Renne, 1994) and (2) lateral displacement of syntectonic strata away from a relatively fixed depocentre by fault movement in the releasing bend of a strike-slip fault (May, Ehmen, Gray & Crowell, 1993). Kinematic and structural features of the Yamaçköy Fault, the geometric shape of the basin and stratigraphic, sedimentological properties of Fevzipaşa Formation support the first model.

7. Conclusions

1. We are the first to document the Early Pleistocene sediments (roughly between 2 and 1 Ma) in the SMB, which comprise a shallow marine fan-deltaic and an alluvial fan to freshwater carbonate depositional packages, separated by intrabasinal unconformities marked by two volcanic ash-fall layers (LASH and UASH).

2. Seven different FA have been distinguished in the Fevzipaşa Formation: (FA 1) hyperconcentrated flow-generated lower alluvial fan deposits, (FA 2) freshwater lacustrine carbonate deposits, (FA 3) prodelta deposits, (FA 4) shallow marine fan-delta slope deposits, (FA 5) nearshore sandy mouth-bar-type fan-delta front deposits, (FA 6) alluvial fan-delta top deposits and (FA 7) hyperconcentrated flow-generated upper alluvial fan deposits.

3. The Fevzipaşa Formation was deposited in front of the Yamaçköy Fault, which was developed on the Miocene supradetachment Söke basin. Owing to the basin-ward progradation of the active faults during the late Pleistocene–Holocene, the PSF was reactivated as an oblique-slip normal fault and formed the northern margin of the SMB.

4. The lateral and vertical relations and environmental interpretations of the Fevzipaşa Formation FAs suggest a shallow marine fan-deltaic progradation in the middle part of the formation. A volcanic ash-fall layer between the non-marine and shallow marine fan-deltaic depositional packages may indicate that the marine transgression occurred after a period of explosive volcanism during the early Early Pleistocene in the Aegean islands. Regional evidence shows that another eruptive event coincided with the regression following the deposition of the shallow marine facies of the Fevzipaşa Formation. Thus, the shallow marine fan-deltaic facies of the Fevzipaşa Formation may have developed between two eruptive phases of Aegean Island volcanism in the Early Pleistocene.

Acknowledgements

This study was supported financially by Dokuz Eylül University Research Projects ‘BAP- 2007. KB. FEN. 047 and 2012. KB. FEN. 017’ and also TÜBİTAK National Science Foundation Grant No. 111Y177. We would like to thank Dr Cemal Tunoğlu, Dr Ayşegül Yıldız, Dr Güler Taner, Dr. Şevket Şen and Alaettin Tuncer for describing our paleontological samples. We also thank Özgür Öztürk, H. Burak Göktaş, İsmet Evsel and Gülin Özkan for their assistance and help during the fieldwork. The paper was edited by International Science Editing, the English language editing service (editage).