Quaternary Activity of the Cihanbeyli and Yeniceoba Fault Zones: ‹Nönü-Eskiﬂehir Fault System, Central Anatolia

Quaternary Activity of the Cihanbeyli and Yeniceoba Fault Zones: ‹nönü-Eskiﬂehir Fault System, Central Anatolia

ERMAN ÖZSAYIN & KAD‹R D‹R‹K

1Hacettepe University, Department of Geological Engineering, Tectonic Research Laboratory, TR-06800 Ankara, TURKEY (e-mail: [email protected])

Abstract: The ‹nönü-Eskiﬂehir fault system (‹EFS) is one of the most important fault systems in Central Anatolia and consists of a series of NW–SE- to WNW–ESE-trending fault zones extending from Uluda¤ (Bursa) in the northwest to Sultanhan› in the southeast. Between ‹nönü and Sivrihisar, the Eskiﬂehir fault zone of the ‹EFS trends WNW, but east of Sivrihisar the ‹EFS changes its direction to NW–SE and splays out into four fault zones, named the Il›ca, Yeniceoba, Cihanbeyli and Sultanhan› fault zones and extends to south of Tuzgölü in the east. The NW–SE- trending Yeniceoba fault zone (YFZ), exposed between Günyüzü in the west and Yeniceoba in the east, controls the northern margin of the Kelhasan horst and the southern margin of the Yeniceoba basin. Along this fault zone two sets of superimposed slickenlines indicate older pure right-lateral strike-slip faulting and younger normal faulting with a right-lateral component. The NW–SE-trending Cihanbeyli fault zone (CFZ) is well exposed between north of Sülüklü in the west and Cihanbeyli in the east. It controls the southern margin of the Kelhasan horst, and is marked by fault scarps, triangular facets, alluvial fans and alignment of springs. Recent detailed field mapping and kinematic analysis along the fault planes between Pliocene lacustrine carbonates and younger fluvial clastic rocks has shown that the CFZ consists of a series of parallel normal faults. However, kinematic analysis of the fault slip-plane data indicates that the fault planes cutting the Pleistocene–Holocene clastic sediments of the Cihanbeyli Graben at the southeastern tip of the CFZ are normal faults with a minor sinistral component. The kinematic analyses of fault-slip data clearly indicate that the area experienced NNE–SSW extension. Recent horizontal terrace deposits cut by a series of steeply-dipping normal faults with minor strike-slip component in ‹lhanyayla, Damlakuyu (Çorca) village and nearly 4 kilometres southeast of ‹nsuyu village, which are located on the YFZ and CFZ, indicate that the activity of both CFZ and YFZ continues, controlled by NNE–SSE-directed extension, in the Quaternary. The distribution of earthquake epicentres supports this view and suggests recent activity along the fault zones.

Key Words: Neotectonic, Quaternary activity, kinematic analysis, Tuzgölü, Central Anatolia, ‹nönü-Eskiﬂehir fault system, Cihanbeyli fault zone, Yeniceoba fault zone

Cihanbeyli ve Yeniceoba Fay Zonlar›’n›n Kuvaterner Aktivitesi: ‹nönü-Eskiﬂehir Fay Sistemi, Orta Anadolu

Özet: Bat›da (Uluda¤), güneybat›da Sultanhan› aras›nda yer alan, gidifli KB–GD ile BKB-–DGD aras›nda de¤iflen bir dizi fay zonundan oluflan ‹nönü-Eskiflehir fay sistemi (‹EFS), Orta Anadolu’daki en önemli fay sistemlerinden birisidir. ‹EFS’nin en bat› ucundaki kolu olan Eskiflehir fay zonu ‹nönü ile Sivrihisar aras›nda BKB–DGD gidifllidir. ‹EFS, Sivrihisar civar›nda do¤rultular› KB–GD olan dört fay zonuna ayr›larak Tuzgölü’nün güneyine kadar devam eder. Bunlar Il›ca, Yeniceoba, Cihanbeyli ve Sultanhan› fay zonlar›d›r. Bat›da Günyüzü, do¤uda Yeniceoba aras›nda yüzeyleyen KB–GD gidiflli Yeniceoba fay zonu (YFZ) Kelhasan yükselimi’nin kuzey kenar›n› ve Yeniceoba Ovas›’n›n güney kenar›n› kontrol eder. Fay düzlemleri üzerinde üst üste (süperimpoze) gözlenen iki fay çizi¤i seti daha eski sa¤ yanal do¤rultu at›ml› bir faylanmay›, ve daha genç olan sa¤ yanal bileflenli normal bir faylanman›n varl›¤›na iflaret eder. KB–GD gidiflli Cihanbeyli fay zonu (CFZ) bat›da Sülüklü kuzeyi, do¤uda ise Cihanbeyli aras›nda çok belirgin olarak yüzeylenir. Kelhasan yükselimi’nin güney kenar›n› kontrol eden fay zonu, fay diklikleri, üçgen yüzeyler, alüvyon yelpazeleri ve su kayna¤› dizilimleri ile karakterize olur. Pliyosen gölsel kireçtafllar› ile daha genç akarsu klastikleri aras›ndaki fay düzlemlerinde yap›lan güncel ayr›nt›l› saha çal›flmalar› ve kinematik analizler CFZ’nun birbirine paralel ve tamamen normal fay karakterli fay serilerinden olufltu¤unu göstermektedir. Halbuki, CFZ’nun güneydo¤u ucunda yer alan Cihanbeyli Grabeni içinde yer alan Pleyistosen–Holosen yafll› klastikleri kesen faylardaki kayma düzlemi verileri bu faylar›n çok az sol yanal at›m bileflenli normal faylar oldu¤unu göstermifltir. Tüm fay düzlemlerinin kinematik analizi ise, bölgenin tansiyonel rejimin etkisi alt›nda oldu¤unu ve genifllemenin KKB–GGD do¤rultusunda geliflti¤ini göstermifltir. YFZ ve CFZ üzerinde yer alan ‹lhanyayla, Damlakuyu köyü ve ‹nsuyu köyünün yaklafl›k 4 km do¤usunda yüzeyleyen, yatay konumdaki güncel taraça çökellerini kesen oldukça dik e¤imli, az miktarda do¤rultu at›m bileflenine sahip normal faylar, Cihanbeyli ve Yeniceoba fay zonlar›n›n her ikisinin de Kuvaterner’de aktif oldu¤unu ve KKD–GGB yönlü bir aç›lman›n etkisinde olduklar›n› belirtir. Aletsel dönemde meydana gelen ve deprem d›fl merkezleri fay zonu üzerinde yer alan depremlerin varl›¤› ise, aktivitenin günümüzde de devam etti¤ini kan›tlamaktad›r.

Anahtar Sözcükler: güncel tektonik, Kuvaterner aktivite, kinematik analiz, Tuzgölü, Orta Anadolu, ‹nönü-Eskiﬂehir fay sistemi, Cihanbeyli fay zonu, Yeniceoba fay zonu

471 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA

Introduction Konya-Eskiflehir neotectonic district west of Tuzgölü is Four major neotectonic structures shape Turkey and the eastern continuation of extension in west-southwest adjacent areas. These are the right-lateral North Anatolia. The ‹nönü-Eskiflehir fault system is the most important shear zone in this district. Numerous previous Anatolian Fault System, the left-lateral East Anatolian and studies pointed out the importance of this system (Ünalan Dead Sea fault systems, and the Aegean-Cyprus active & Yüksel 1978; fiaro¤lu et al. 1987; Koçyi¤it 1991; subduction zone. Besides these major structures, there Koçyi¤it et al. 1991; Dirik & Göncüo¤lu 1995; Koçyi¤it & are some second order structures which divide the Beyhan 1998; Altunel & Barka 1998; Bozkurt 2001; Anatolian plate into smaller blocks. These second order Koçyi¤it & Erol 2001; Dirik & Erol 2003; Koçyi¤it 2003, structures are the left-lateral Central Anatolian Fault 2005). The WNW–ESE-trending western part of the System, the right-lateral Tuzgölü Fault Zone, the ‹nönü- system is exposed between Uluda¤ and NW of Sivrihisar. Eskiflehir fault system (‹EFS) and the Akflehir oblique-slip Northwest of Sivrihisar, the system changes its trend to normal fault zones (Dirik & Göncüo¤lu 1996; Koçyi¤it & NW and splays into three branches, namely the Ilıca, Beyhan 1988; Koçyi¤it et al. 2000; Dirik 2001; Koçyi¤it Yeniceoba and Cihanbeyli fault zones (Koçyi¤it 1991; 2003, 2005; Koçyi¤it & Özacar 2003; Dirik & Erol Çemen et al. 1999; Dirik & Erol 2000, 2003; Koçyi¤it & 2003). The North Anatolian and the East Anatolian fault Özacar 2003; Koçyi¤it 2005). The shear zone merges systems are the intracontinental plate boundaries, active with the Altınekin fault zone southeast of Cihanbeyli. This since the Late Pliocene, along which the Anatolian plate is fault zone was first called the ‘Zıvarık Fault System’ by escaping to the WSW onto the oceanic lithosphere of the Erol (1969), but with the name change from Zıvarık to African plate along the Aegean-Cyprus subduction zone Altınekin, it has been renamed the ‘Altınekin fault zone’ (e.g., Koçyi¤it & Beyhan 1998; Koçyi¤it & Özacar 2003; by Dirik & Erol (2003, Figure 1). However, at the same Yaltırak et al. 2005; Kaymakcı et al. 2006; Aksoy et al. time the fault zone was also named the ‘Konya-Bulok 2007; Bektafl et al. 2007). fault zone’ by Koçyi¤it (2003). In this study, we prefer to Within these major structures four Neotectonic utilize the name ‘Altınekin fault zone’, as the type locality provinces can be defined, namely: East Anatolian of this fault zone is in ‘Altınekin County’ where it is contractional province, North Anatolian province, Central characterized by seismically active grabens, hence the Anatolian province and West Anatolian province (fiengör priority of this terminology. The southeastern extension et al. 1985; Bozkurt 2001). The East Anatolian of the ‹EFS is the Sultanhanı fault zone (Figure 1). Altunel contractional province is characterized by an N–S & Barka (1998) stated that the western part of this zone compressional tectonic regime. The North Anatolian consists of sinistral oblique faults with a normal Province, located north of the North Anatolian Fault component and separates the Aegean/Western Anatolian System (NAFS), is characterized by numerous strike-slip block from the Central Anatolian block. Koçyi¤it (2003) faults with a strong E–W thrust component (fiengör et al. named the fault zone the ‹nönü-Eskiflehir fault zone and 1985). The West Anatolian Province is characterized by based on more recent studies (Koçyi¤it 2005) concluded NNW–SSE continental extension; E–W-trending grabens that it is the north-northeast boundary of the southwest and intervening horsts are its most prominent features Turkey extensional province. Although the existence of (e.g., Bozkurt & Mittwede 2005; Erkül et al. 2005; the ‹EFS has been known for years and its western part Tokcaer et al. 2005; Yücel-Öztürk et al. 2005; Ersoy & is well defined, few kinematic studies have been made in Helvacı 2007 and references therein). The Central the eastern part of this mega shear zone, and they cannot Anatolian Province, located between the NAFS in the represent the whole character of, and deformation stages north, the East Anatolian Fault System (EAFS) in the east, within the southeastern part of the fault system. and a transition zone in the west, extends nearly N–S The main objective of this paper is therefore to along the 37°30´ east meridian (Dirik & Göncüo¤lu 1996; present new kinematic field data from different locations Koçyi¤it & Beyhan 1998; Dirik 2001; Koçyi¤it & Erol along the southern branches of the shear zone, namely 2001; Dirik & Erol 2003; Koçyi¤it & Özacar 2003; the Cihanbeyli and Yeniceoba fault zones (Figure 2), to Koçyi¤it 2005). East of Tuzgölü it is mostly characterized determine their initiation times and to show the by a contractional-extensional tectonic regime, and mainly Quaternary–Recent tectonic activity of both the strike-slip faults. Koçyi¤it & Erol (2001) stated that the Cihanbeyli and Yeniceoba fault zones.

472 E. ÖZSAYIN & K. D‹R‹K

0 310 00’ 320 00’ ANKARA 33 00’ 340 00’

İnönü ESKİŞEHİR KIRIKKALE

ESKİŞEHİR FAULT ZONE Keskin Polatlı

FAULT Sivrihisar Bala 0 Haymana 39 30’ ZONE Akpınar Günyüzü Kaman ILICA FAULT ZONE N Ilıca ZONE 0 60 km YENİCEOBA FAULT ZONE KIRŞEHİR Akgöl CİHANBEYLİ FAULT ZONE Kulu Ş.Koçhisar Yeniceoba TUZ GÖLÜ FAULT ZONE AFYON Yunak Lake Çay Eber TUZ GÖLÜ Ortaköy Sultandağı Cihanbeyli SULTANHANI FAULT ZONE AKŞEHİR FAULTLake ZONE Sandıklı Akşehir 380 30’ Akşehir AKSARAY ZONE Ilgın Altınekin FAULT ZONESultanhanı

Hoyran FAULT HASANDAĞ Quaternary alluvial fan 3268 deposits and talus 0 Pleistocene-Quaternary 38 00’ basin deposits ALTINEKİN FAULT ZONE KONYA Miocene-Quaternary volcanics study area Karapınar KARACADAĞ lake oblique-slip strike-slip fault fault Ereğli 370 30’ normal fault with burried fault shown hanging wall 320 00’ 330 00’ 340 00’

Figure 1. Tectonic map of the study area and surrounding regions (modified from Dirik & Göncüo¤lu 1996; Göncüo¤lu et al. 1996; Dirik 2001; Dirik & Erol 2003; Koçyi¤it & Özacar 2003).

Stratigraphy basement and are covered by Paleocene red terrestrial clastic rocks. This unit grades up and laterally into Upper The units exposed in the study area are subdivided into Paleocene–Lower Eocene shallow marine rocks. The latter two main categories. The Oligo–Miocene and younger sequence starts with sandy-clayey limestone at the base, units are considered as cover units while older rocks are overlain in turn by a marl-sandstone alternation and regarded as the basement units (Figure 3). fossiliferous limestone. These carbonates are unconformably overlain by Eocene yellow nummulitic Basement Units limestone and a greenish grey sandstone-shale alternation. The oldest basement units exposed in the south of the area are the Kütahya-Bolkarda¤ı metamorphics (KBM) Cover Units (Özcan et al. 1990), composed mainly of The Gökda¤ Formation (Göncüo¤lu et al. 1996), Palaeozoic–Mesozoic platform carbonates. In the north comprising the oldest cover rocks, consists entirely of and west of the study area, ophiolitic rocks form the terrestrial sediments and overlies basement rocks with

473 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA

b N Kuşça CİHANBEYLİ half-graben (Çorca) Damlakuyu Ova Yeniceoba İlhanyayla YENİCEOBA İnsuyu Çıngırık Kütükuşağı Kuşça Pınarbaşı Büyükbeşkavak Perspective relief map of the study area. (b) Tuğtepe Küçükbeşkavak Kelhasan Böğrüdelik Yeniceoba Fault Zone Kelhasan Horst Kandil Tüfekçipınarı Harabe Zaferiye Cihanbeyli Fault Zone Hatırlı Ortakışla SÜLÜKLÜ Simplified map showing major neotectonic structures shaping Turkey. Hacıömeroğlu a Figure 2. (a)

474 E. ÖZSAYIN & K. D‹R‹K

LITHOLOGY DESCRIPTION

AGE

UNIT

C: Recent alluvium B C B: Recent alluvial fan deposits

Holocene A A: terrace deposits disconformity e e: carbonate, gypsum and sulphate facies d: sand-clay facies d c: lime-clay facies c

Tuzgölü b: silt-clay facies

b tilted slightly

Pleistocene

a a: grey gravel-sand facies towards Tuzgölü

n: white-cream, porous, thick-bedded lacustrine

limestone and thin- to medium-bedded claystone neotectonic period alternation (extensional regime) n m: light brown-red, unsorted, carbonate cemented, z polygenic conglomete-sandstone alternation

z: light brown-cream, mudstone-tuffite alternation

Pliocene y y: light brown, sandy claystone-mudstone alternation with conglomerate intercalations Cihanbeyli x: light brown-cream, unsorted, thick-bedded xmpolygenetic conglomerate-coarse sandstone

Kuşça member alternation angular unconformity ? greyish white Triassic crystalline limestone blocks and ophiolitic mélange

yellow to green claystone-mudstone-sandstone alternation

Gökdağ brick red, thick- to thin-bedded conglomerate-sandstone alternation

Oligo-Miocene angular unconformity Paleocene-Eocene shallow-marine carbonates Paleocene terrestrial clastics

palaeotectonic period

(contractional regime)

rocks ophiolitic mélange

basement Kütahya-Bolkardağı metamorphics

Figure 3. Generalized tectono-stratigraphic columnar section of the study area.

475 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA

angular unconformity (Figure 3). A basal alternation of Fault System by Dirik & Erol (2003) and the ‹nönü- grey conglomerate and sandstone is overlain by a red Eskiflehir Fault Zone by Koçyi¤it (2003). The type conglomerate-mudstone alternation. Gypsum occurs in locality of this shear zone is ‹nönü County (Koçyi¤it the upper levels of the formation occasionally. 2003), and it has therefore been named the ‘‹nönü- The Pliocene Cihanbeyli Formation overlies the Eskiflehir fault zone’. Detailed field studies have shown Gökda¤ Formation and older units with angular that this mega shear zone includes four fault zones, unconformity (Figure 4) and is composed of very thick- namely the Ilıca, Yeniceoba, Cihanbeyli and Sultanhanı bedded white to cream, porous limestone and claystone. fault zones (Çemen et al. 1999; Dirik & Erol 2003; In the southern part of Yeniceoba, the formation is Özsayın & Dirik 2005). Therefore, the rank of ‹nönü- characterized by grey, well-sorted, polygenetic Eskiflehir fault zone is shifted up to ‘system’ and conglomerate and a light grey, coarse- to medium- renamed as ‘‹nönü-Eskiflehir fault system’ (‹EFS) in this grained sandstone alternation at the base, overlain by a paper. The WNW–ESE-trending western part of the grey-red mudstone-tuffite alternation, named here the system, the Eskiflehir fault zone, is exposed between Kuflça member. The most diagnostic character of the Uluda¤ and NW of Sivrihisar, where it controls the Kuflça member is its tuffite content. The following southern margins of the incipient Eskiflehir graben Ostracoda fauna were found in this formation by Tuno¤lu (Koçyi¤it 2003). According to Koçyi¤it (2003), two sets et al. (1995): Cyprideis torosa Jones, 1850; Candona of superimposed slickensides indicate older dextral (Candona) neglecta Sars, 1888; Candona (Candona) strike-slip faulting (contractional phase) and younger paralella pannonica Zalanyi; Candona (Candona) altoides normal faulting (extensional phase). Northwest of Petkovski, 1961; Candona (Pseudocandona) compressa Sivrihisar, the system changes its trend to SE and splays Koch 1837; Heterocypris ponticus Krstic, 1973. Based into three branches, namely the Ilıca, Yeniceoba and on these fauna present in limestone levels of the Cihanbeyli fault zones. The southeastern extension of sequence, a Pliocene age was assigned to the Cihanbeyli the ‹EFS is the Sultanhanı fault zone (Figure 1). The Formation by Tuno¤lu et al. (1995) and Beker (2002). present study is concerned with the Cihanbeyli fault zone and the eastern part of the Yeniceoba fault zone. The Cihanbeyli Formation grades up into the Pleistocene Tuzgölü Formation (Ulu et al. 1994), comprising poorly consolidated conglomerates and Cihanbeyli Fault Zone sandstones with carbonate, gypsum and sulphate deposits The Sivrihisar-Cihanbeyli branch of the fault system was in the upper levels. The unit dips gently to the E/ESE first named the Sivrihisar-Cihanbeyli fault zone by Dirik & towards Tuzgölü; cross bedding in sandy beds is the most Göncüo¤lu (1995). But, as it is well exposed between important syn-sedimentary structure. Sülüklü and Cihanbeyli, and the type locality is west of Quaternary alluvial fans adjacent to fault scarps of the Cihanbeyli county, it was renamed the Cihanbeyli fault Cihanbeyli fault zone, terrace deposits, slope debris, zone by Çemen et al. (1999). The Cihanbeyli fault zone sodium sulphate deposits around Bolluk Lake, and recent (CFZ) is about 80 km long and well exposed between alluvial deposits of the ‹nsuyu stream are the youngest Cihanbeyli in the east and northwest of Sülüklü in the lithologies in the study area. They all unconformably west (Figures 1, 2 & 5). It is the southern branch of the overlie the older rocks (Figure 3). ‹EFS and consists of a set of parallel faults. The fault zone trends approximately N50°W between Cihanbeyli and Sülüklü, then changes its direction to N25°W. The central ‹nönü-Eskiflehir Fault System and western faults of this zone have south dipping fault An approximately 470-km-long and WNW–ESE- to planes whereas the eastern faults have both north- and NW–SE-trending active mega shear zone is exposed south-dipping planes which form a very characteristic between Uluda¤ in the west and Sultanhanı in the east. extensional structure first described by (Erol 1969, This mega shear zone forms a transitional boundary figures 8 & 9) as the ‘Cihanbeyli-‹nsuyu fault valley’ between continental extension in the south and strike- (Figure 6). This extensional structure, later described as slip faulting in the north (Koçyi¤it 2003). This structure a graben and named the ‘Cihanbeyli graben’ by Koçyi¤it was simultaneously named the Eskiflehir-Sultanhanı (2005), is an approximately 0.4-km-wide and 15-km-

476 E. ÖZSAYIN & K. D‹R‹K

SW Cihanbeyli Formation NE Kuşça member Paleocene-Eocene ophiolitic mélange shallow-marine carbonates

Gökdağ Formation

Paleocene terrestrial clastics

Recent alluvion

S450 W

150 NE 33 cm 3300

a b

Figure 4. (a) General view showing the compressional low-angle tectonic boundary (thrust) between the basement rocks and Gökda¤ Formation, and Pliocene Kuﬂça member of Cihanbeyli Formation sealing this compressional regime. (b) Close-up view of the tectonic boundary between ophiolitic mélange and Gökda¤ Formation. long and NW–SE-trending Quaternary depression located NW–SE-trending faults. Fault planes of this zone are between the Cihanbeyli and Çıngırık fault zones (Figures steeper than those of the CFZ and have both NE and SW 5 & 6). The graben affects the Pliocene Cihanbeyli dip directions. The YFZ controls both the northern margin formation and is filled by Pleistocene–Holocene fluvial of Kelhasan horst and the southern margin of Yeniceoba sediments. Beyond Çıngırık, the fault zone controls the basin (Figure 2). This fault zone is characterized by linear southern margin of the Kelhasan horst, and is valleys, fault scarps in the middle and northwestern and characterized by fault scarps, triangular facets, alluvial alignment of alluvial fans in the southeastern parts. In the fans and alignment of springs (Figure 2). southeast of this zone, there is a suspended basin named the Kuﬂça half-graben (Figure 2).

Yeniceoba Fault Zone A fault plane, seen west of Kütükuﬂa¤ı village, displays two different sets of slickenlines (Figure 7). The first set The Yeniceoba fault zone (YFZ) (Çemen et al. 1999), of slickenlines are horizontal and give right-lateral exposed between the southeastern part of Yeniceoba in the movement, while the second set show normal fault east and Günyüzü town in the west, is about 130 km long movement with right-lateral component. The oblique (Figures 1 & 5). Like the CFZ, this zone consists of slickenlines cut the horizontal ones (Figure 7). This

477 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA

Hacıömeroğlu

Figure 9 Ortakışla Kandil

Hatırlı Figure 6 Kütükuşağı CİHANBEYLİCİHAN FAULT ZONE Kelhasan YENİCEOBAYE FAULT ZONE Sülüklü NİC B Yeniceoba EYLİ FAU E Zaferiye O Harabe BA FAUFigure 8 Kuşça LT LT Figure 7 Z Z N Böğrüdelik O Figure 11 O N N 010km E E Figure 12 Tuğtepe Damlakuyu

sites of stations where Pınarbaşı Figure 13 slip data were measured Çıngırık Figure 15 sites of stations where İnsuyu Figure 5 photos were taken İlhanyayla Cihanbeyli graben normal fault with shown hanging wall Figure 16 Cihanbeyli

Figure 5. The map of Cihanbeyli and Yeniceoba fault zones illustrating their segments and sites of observations where slip-data were measured.

situation represents a two-stage deformation on this fault Kinematic Analysis zone. A stereographic plot of the first set of fault slip-plane During field work in the summers of 2004, 2005, 2006 data indicates that they are right-lateral strikeslip fault and 2007 we mapped the fault zone in detail. Special with N–S-directed compression on them (Figure 7). attention was given to fault planes with slip lines. The Besides, some fault slip-plane data are measured from a data was acquired from 10 stations, namely road cut near Damlakuyu village (north of Cihanbeyli). The Hacıömero¤lu, Kuflça, Tu¤tepe, Pınarbaflı, Çıngırık, host unit is the fluvial clastics of the Tuzgölü Formation ‹nsuyu, 4 km east of ‹nsuyu, ‹lhanyayla (2 stations) and and Quaternary deposits. These sediments are cut by Damlakuyu (Figures 5; Table 1). NW–SE-trending and steeply north-dipping normal faults. A stereographic plot of these fault slip-plane data indicates a NNE–SSW-directed extension (Figures 8 & 10j). Hacıömero¤lu Deformation on the Yeniceoba fault zone around Hacıömero¤lu is at the northwestern end of the Kuflça village was also carefully investigated. Basement Cihanbeyli fault zone (Figure 9a). 28 fault- slip data were rocks are thrust onto the Gökda¤ Formation and the taken from this location. Slickenlines are the main Kuflça member of Cihanbeyli Formation overlies this indicators (Figure 9b, c). The host unit is the Gökda¤ σ thrust belt with angular unconformity (Figure 4). Beds of Formation. The principal stress distribution is 1= σ σ the Kuflça member are horizontal and show no evidence 013°/75°, 2= 105°/01° and 3=195°/15° (Figure 10a, of N–S compression. Hence, this is important evidence for b). showing that the compressional-contractional regime (palaeotectonic period) ended at the end of Miocene.

478 E. ÖZSAYIN & K. D‹R‹K

NE SW

1050 m Ortakale Kale CİHANBEYLİ

NE SW

Figure 6. Close-up (a) and general (b) views of the Cihanbeyli graben.

Kuflça Pınarbaflı Kuflça village is southwest of Yeniceoba. 4 fault- slip data 22 measurements of fault slip data were taken from were taken, and slickenlines were the main indicators. Pınarbaflı village. The dominant fault type is pure dip slip The host unit is the Kuflça member of Cihanbeyli (Figure 11a). Slickenlines, fault breccia are the main σ Formation. The principal stress distribution is 1= indicators (Figure 11b) and a big spring supplying water σ σ 098°/77°, 2= 323°/09° and 3= 232°/09° (Figure 10a, to the ‹nsuyu Stream exists at this location (Figure 11c). σ σ c). The principal stress distribution is 1= 031°/71°, 2= σ 293°/03° and 3= 202°/19° (Figure 10a, e). Tu¤tepe Tu¤tepe is located approximately 5 km SE of Bö¤rüdelik Çıngırık village (Figure 6), at the point where the normal fault 23 measurements of fault- slip data were taken from the stepped right. Fault breccia is the dominant indicator but fault scarps north of Çıngırık village (Figure 5). The host only 4 slickenlines could be determined at this location. unit is the Pliocene Cihanbeyli Formation. Slickenlines and σ σ The principal stresses are 1= 036°/73°, 2= 300°/02° fault breccia are the dominant indicators of the fault σ and 3= 209°/17° (Figure 10a, d). (Figure 12a, b). 21 slip data are pure dip slip and the

479 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA

first phase (right-lateral) second phase (normalwith right-lateral comp.)

s horizontal 1 s 55 mm component of 3

s2 horizontal s s component of 1 b 3

Figure 7. General (a) and close-up (b) views of the fault plane which have two superimposed slickenlines observed at the west of Kütükuﬂa¤ı σ σ σ village; (c) stereographic plots of fault slip plane data on Schmidt lower hemisphere, 1, 2, 3 are principal, intermediate and least stress axes, respectively. other two are normal with a sinistral component. The 4 km East of ‹nsuyu σ σ principal stresses are 1= 017°/75°, 2= 110°/01° and At this location, nearly 4 km east of ‹nsuyu village, the σ 3= 200°/15° (Figure 10a, f). Cihanbeyli graben is located (Koçyi¤it 2005). A set of faults cuts Quaternary alluvium and the dominant fault ‹nsuyu type is normal with a minor sinistral component. The main indicators are the slickenlines. The strikes of the 13 measurements of fault- slip data taken from north of faults change between N30°W and N65°W. The ‹nsuyu village are shown in Figure 5. The host unit is the displacements of the blocks are 30 cm to 60 cm (Figures Cihanbeyli Formation. At this location most faults are 12 & 13). The principal stress distribution of the normal faults with a dextral component (Figure 10). The σ σ Quaternary faults are 1= 202°/72°, 2= 296°/01° and main faulting and a splay fault intersect and form a fault σ = 026°/18°, respectively (Figure 10a, h). wedge at ‹nsuyu (Figure 13). This wedge is a releasing 3 wedge and the faults form a little graben structure. Slickenlines, fault breccia and flat iron faces are the σ indicators. The principal stress distribution is 1= 001°/69°, σ σ 2= 153°/18° and 3= 246°/09° (Figure 10a, g).

480 E. ÖZSAYIN & K. D‹R‹K

26 mm

45 cm

Figure 8. General (a) and close-up (b) views of the fault observed at Damlakuyu village near the road-cut.

W N

Hacıömeroğlu

28 cm c + _ ~N25W 33 cmcm

b a

Figure 9. General and close-up views of Hacıömero¤lu station and fault planes.

481 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA are 3 n=8 σ n=28 , 2 σ , 1 σ (j) (h) (i) 1 2 3 a s s s on Schmidt lower hemisphere, 3 s CİHANBEYLİ Damlakuyu Büyükkartal horizontal component of (g) YENİCEOBA İnsuyu Kütükuşağı Çıngırık n=21 n=12 n=4 Kuşça Pınarbaşı Böğrüdelik (f) Harabe n=22 N Zaferiye Hatırlı Hacıömeroğlu 010km sites of stations where slip-data were measured residentials Ortakışla Ortakışla SÜLÜKLÜ (e) n=4 n=5 n=28 principal, intermediate and least stress axes, respectively. Shaded relief map showing the sites of stations where slip-data were measured and stereographic plots of fault- slip plane data (b) (d) (c) Figure 10.

482 E. ÖZSAYIN & K. D‹R‹K

Table 1. Measurements of slickensides and slickenlines on Hacıömero¤lu, Kuﬂça, Tu¤tepe, Pınarbaﬂı, Çıngırık, ‹nsuyu, 4 km east of ‹nsuyu, ‹lhanyayla (2 stations) and Damlakuyu stations.

Location No Dip direction Dip amount Rake Sense Principal φ (ºN) (º) (º) stress axes

1 115 34S 89S Normal 2 120 65S 89S Normal 3 160 58S 60S Normal 4 150 57S 20S Dextral 5 118 40S 89S Normal 6 122 69S 89S Normal 7 117 43S 89E Normal 8 143 89S 89S Normal 9 130 80S 89S Normal 10 118 73S 89S Normal 11 117 40S 89S Normal 12 132 80S 89S Normal σ 13 130 67S 89S Normal 1 = 013º / 75º σ Hac›ömero¤lu 14 120 69S 89S Normal 2 = 105º / 1º 0.315 σ 15 235 73N 30W Dextral 3 = 195º / 15º 16 140 79S 89S Normal 17 256 66N 40W Dextral 18 135 89S 89S Normal 19 120 15S 89S Normal 20 112 87S 50W Sinistral 21 124 70S 89S Normal 22 122 54S 60E Normal 23 110 64S 89S Normal 24 95 37S 89E Normal 25 85 75S 89W Normal 26 120 88S 89S Normal 27 135 88S 89S Normal 28 112 70S 89S Normal

1 330 67S 89S Normal σ Tu¤tepe 2 320 60S 89S Normal 1 = 036º / 73º 0.185 σ 3 310 78S 89S Normal 2 = 300º / 2º σ 4 295 72S 89S Normal 3 = 209º / 17º

1 100 80S 89E Normal 2 95 78S 89E Normal 3 125 72S 89E Normal 4 100 70S 89E Normal 5 110 70S 89E Normal 6 115 82S 89E Normal 7 120 54S 89E Normal 8 100 89S 89E Normal 9 100 61S 89E Normal σ 10 135 89S 89E Normal 1 = 031º / 71º σ P›narbaﬂ› 11 140 70S 89E Normal 2 = 293º / 3º 0.167 σ 12 135 65S 89E Normal 3 = 202º / 19º 13 130 89S 89E Normal 14 130 61S 89E Normal 15 140 60S 89E Normal 16 150 65S 89E Normal 17 130 68S 89E Normal 18 150 60S 89E Normal 19 115 65S 89E Normal 20 120 65S 89E Normal 21 122 66S 89E Normal 22 145 55S 89E Normal

483 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA

Table 1. (Continued).

Location No Dip direction Dip amount Rake Sense Principal φ (ºN) (º) (º) stress axes

1 125 63S 89E Normal 2 110 64S 89E Normal 3 115 88S 89E Normal 4 140 42S 89E Normal 5 112 38S 89E Normal 6 125 62S 89E Normal 7 116 62S 89E Normal 8 113 64S 89E Normal 9 147 51S 89E Normal σ 10 145 75S 89E Normal 1 = 017º / 75º σ Ç›ng›r›k 11 175 75E 89S Normal 2 = 110º / 1º 0.233 σ 12 150 51S 89E Normal 3 = 200º / 15º 13 140 66S 89E Normal 14 128 45S 89E Normal 15 135 66S 89E Normal 16 125 70S 89E Normal 17 150 59S 89E Normal 18 135 68S 89E Normal 19 155 60S 89E Normal 20 120 75S 89E Normal 21 125 85S 89E Normal

1 110 80S 55W Normal 2 115 73S 57W Normal 3 114 85S 35W Normal 4 125 86S 50W Normal σ 5 125 89S 89S Normal 1 = 001º / 69º σ ‹nsuyu 6 135 60S 55W Normal 2 = 153º / 18º 0.390 σ 7 140 70S 71W Normal 3 = 246º / 9º 8 145 65S 89S Normal 9 140 61S 55W Normal 10 141 56S 70W Normal 11 179 62W 78S Normal 12 145 46S 58W Normal

1 300 80N 70W Normal 2 295 78N 68W Normal 4 km east 3 330 67N 70W Normal σ of ‹nsuyu 4 325 76N 70W Normal 1 = 242º / 68º σ 5 328 68N 75W Normal 2 = 099º / 18º 0.273 σ 6 310 70N 72W Normal 3 = 005º / 12º 7 308 80N 70W Normal 8 070 60N 75W Normal

1 25 71B 89N Normal σ ‹lhanyayla 2 35 75B 89N Normal 1 = 140º / 69º σ 3 45 81B 80N Normal 2 = 256º / 10º 0.206 σ 4 50 80B 80N Normal 3 = 349º / 18º

1 345 10D 89N Normal σ Kuﬂça 2 325 30D 89N Normal 1 = 098º / 77º σ 3 335 15D 89N Normal 2 = 323º / 9º 0.498 σ 4 310 30G 89N Normal 3 = 232º / 9º

484 E. ÖZSAYIN & K. D‹R‹K

Table 1. (Continued).

Location No Dip direction Dip amount Rake Sense Principal φ (ºN) (º) (º) stress axes

1 310 89K 2N Sinistral 2 320 89K 2N Sinistral 3 38 84G 10S Dextral 4 328 59G 89N Normal 5 313 75K 89N Normal 6 345 68D 89N Normal 7 280 56K 89E Normal 8 60 35G 80W Normal 9 50 30G 80W Normal 10 305 80G 2S Sinistral 11 280 79K 89E Normal σ 12 40 89K 1E Dextral 1 = 151º / 77º σ 13 100 71K 89E Normal 2 = 272º / 0º 0.425 σ Damlakuyu 14 85 33G 89E Normal 3 = 003º / 11º 15 315 60K 89E Normal 16 115 46K 70S Normal 17 125 44K 89E Normal 18 60 44G 80W Normal 19 70 30G 89E Normal 20 320 56K 89E Normal 21 345 43D 89N Normal 22 310 49K 89E Normal 23 80 45G 89E Normal 24 122 55G 60E Normal 25 110 35K 89E Normal 26 135 35K 89E Normal 27 90 82K 80E Normal 28 20 25G 45S Normal

1 320 80N 1W Dextral σ Kütükuﬂa¤› 2 322 80N 1W Dextral 1 = 182º / 11º σ bat›s› 3 315 80N 1W Dextral 2 = 068º / 65º 0.302 σ 4 318 80N 1W Dextral 3 = 277º / 23º

‹lhanyayla Damlakuyu At this location two different faults, approximately 400 m Damlakuyu is north of Cihanbeyli. Field work in 2006 apart, cut the Quaternary units. Additionally, four included observation of a new road cut in which Tuzgölü measurements of fault-slip data could be taken from both Formation, Quaternary units and the NW–SE-trending locations (Figure 16), so the slip data are evaluated faults can be seen clearly. The fault planes dip both NE together. Slickenlines are the main indicators at two and SW. There are also some second order conjugate locations. The displacements of the blocks range from 10 faults. Slickenlines are the main indicators. The cm to 120 cm. The principal stresses distribution of the displacements on fault planes range from 5 cm to 40 cm σ σ ‹lhanyayla faults are 1= 140°/69°, 2= 256°/10° and (Figure 8). The principal stresses distribution the faults σ σ σ σ 3= 349°/18°, respectively (Figure 10a, i). are 1= 151°/77°, 2= 272°/07° and 3= 003°/11°, respectively (Figure 10a, j).

485 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA

b N S

85 mmmm

Pınarbaşı

250 cmcm

c a

Figure 11. General (a) and close-up (b) views of Pınarbaﬂı station; (c) fault plane and artificial pool in front of the Pınarbaﬂı spring.

S N

Çıngırık

175 175 cm

6cm b a

Figure 12. General and close-up views of slickensides at Çıngırık station.

486 E. ÖZSAYIN & K. D‹R‹K

N50W İnsuyu

S N NW SE

175175 cm cm

b c

Figure 13. General (a) and close-up views of ‹nsuyu station and fault planes forming the fault wedge (b, c).

SW Quaternary NE faults

İnsuyu Stream

Not to scale B AB İnsuyu A (b)

alluvium

talus

Cihanbeyli Formation

location of Quaternary faults a normal fault with shown hanging wall

Figure 14. (a) Shaded relief map of ‹nsuyu village and surroundings. (b) Sketched geological cross section showing the relationship between main fault and Quaternary faults.

487 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA

N S N S

176 cm

a b

S N N S

c d

66cmcm

e f 26 mm Figure 15. General view of fault planes cutting Holocene deposits at 4 km east of ‹nsuyu village (a-d) and close-up view of fault seen on (d). Slickenlines indicate normal faulting with a minor amount of sinistral strike-slip component.

488 E. ÖZSAYIN & K. D‹R‹K

E W

175 cm

E W

c b

Figure 16. Three photographs illustrating general (a, b) and close-up views (c) of the faulting in Quaternary alluvium at ‹lhanyayla village.

489 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA

0 0 0 0 0 34 00’ 32 30’ earthquake0 epicentres 33 30’ 31 30’ 32 00’ 33 00’ ESKİŞEHİR and magnitudesANKARA lake KIRIKKALE 2>M>=3.9 strike-slip fault 5>M>=4 normalKeskin fault with Polatlı shown hanging wall 6>M>=5Bala 0 normal fault with 39 30’ Sivrihisar strike-slip component Haymana 0 M>=6 39 30’ İNÖNÜ- ESKİŞEHİR burried fault Akpınar Kaman

TUZGÖLÜ FAULT ZONE Kulu

390 00’ 390 00’ Ş.Koçhisar AFYON Yunak FAULT SYSTEM

Bolvadin Tuzgölü

AKŞEHİRSultandağı Cihanbeyli 380 30’ 380 30’ Akşehir FAULT ZONE AKSARAY N Ilgın Altınekin Sultanhanı 0 50 km

0 0 31 00’ 31 30’ 320 00’ 320 30’ 330 00’ 330 30’ 340 00’

Figure 17. Seismotectonic map of the Cihanbeyli and neighboring fault zones (modified from Dirik & Erol 2003).

There are no reported damaging historical Yeniceoba basin. Recent field observations and kinematic earthquakes on the Cihanbeyli fault zone. But the analyses show the YFZ to have two stages of epicentres of earthquakes with magnitudes ranging from deformation. The first stage has right-lateral strike-slip 2 to 5 show the seismic activity of the zone in recent time faulting which must be evaluated by N–S compressional (Figure 17). regime due to pure shearing. The second stage was normal faulting with right-lateral component. The latest faulting observed on the road-cut near Damlakuyu gives Discussion and Conclusions us the NNE–SSW-directed extension. This result reveals The mega shear zone extending from Uluda¤ in the west that the YFZ and EFZ were formed and evolved at similar to Sultanhanı in the east is composed of a series of times with similar character and consistent with NW–SE- to WNW–ESE-trending fault zones, namely the Koçyi¤it’s results (2005). Eskiflehir (EFZ), Ilıca (previously named the ‘Ilıca fault set’ The southern branch of the ‹EFS, the Cihanbeyli fault by Koçyi¤it 1991), Yeniceoba (YFZ), Cihanbeyli (CFZ) and zone, between Sülüklü in the northwest and Cihanbeyli in Sultanhanı (SFZ) fault zones. Since this mega shear zone the southeast, controls the southern margin of Kelhasan is not a single fault zone, but composed of different fault horst. Stereographic plots of the fault slip-plane data zones, the rank of the ‹nönü-Eskiflehir fault zone was obtained from the southern margin-faults of Kelhasan shifted up to ‘system’ and renamed the ‘‹nönü-Eskiflehir horst, show that the CFZ movement was purely normal fault system’ (‹EFS). The YFZ controls both the northern faulting. The zone trends N50°W, dips to the south, and margin of Kelhasan horst and the southern margin of its active extension direction is approximately NE–SW.

490 E. ÖZSAYIN & K. D‹R‹K

The Cihanbeyli graben, at the southeastern tip of the CFZ, final stage (NNE–SSW extension) of the YFZ and the is an important structure of this zone. Formed on the whole character of the CFZ shows that the formation of Pliocene Cihanbeyli formation, it was filled by CFZ is later than the formation of the YFZ. Fault trends Pleistocene–Holocene fluvial sediments. Kinematic in the Oligo–Miocene Gökda¤ Formation and Pliocene analysis of the fault slip-plane data indicates that they are Cihanbeyli Formation are nearly parallel to Quaternary normal faults with a minor sinistral component with fault trends, and the kinematic results are similar. This NNE–SSW-directed extension on them. However, based indicates that the earliest initiation of motion along the on his stereographic plot of fault slip-plane data, Koçyi¤it CFZ is Late Pliocene and both the Cihanbeyli and (2005, figure 40a) indicated the presence of NNW–SSE Yeniceoba fault zones are active in the Quaternary. This extension on margin-bounding faults of the graben and result is also consistent with the results of Koçyi¤it faults cutting Holocene graben fill. But, our results (2003). remain consistent with the regional results of Koçyi¤it (1991, 2005). Acknowledgements The above- mentioned situations reveal that the YFZ The field work was supported by Hacettepe University was initiated as a right-lateral strike-slip fault before the Scientific Research Fund project no 02 02 602 012. Pliocene and continues to move with dextral strike-slip Special thanks are due to Bülent Akıl for help during field deformation with N–S-directed compression. This studies. The authors also wish to express their thanks to compressional phase was followed by extensional two reviewers, for valuable and constructive comments faulting. However, only the CFZ shows NNE–SSW and contributions. John A. Winchester helped with the extension on every part of it. Comparison between the English of the final text.

References

AKSOY, E., ‹NCEÖZ, M. & KOÇY‹⁄‹T, A. 2007. Lake Hazar Basin: a negative D‹R‹K, K. 2001. Neotectonic evolution of the northwestward arched flower structure on the East Anatolian Fault System (NAFS), SE segment of the Central Anatolian Fault Zone, central Anatolia, Türkiye. Turkish Journal of Earth Sciences 16, 319–338. Turkey. Geodinamica Acta 14, 147–158.

ALTUNEL, E. & BARKA, A. 1998. Neotectonic activity of Eskiflehir fault D‹R‹K, K. & EROL, O. 2000. Tuzgölü ve civarının tektonomorfolojik zone between ‹nönü and Sultandere. Geological Bulletin of Turkey evrimi [Tectonomorphologic evolution of Tuzgölü and 41, 41–52 [in Turkish with English abstract]. surrounding area]. Haymana-Tuzgölü-Ulukıflla Basenleri Uygulamalı Çalıflması, Aksaray, Abstracts, p. 7–8. BEKER, K. 2002. ‹nsuyu Kireçtaflları (Karapınar/Konya) Ostrakod Toplulu¤unun Biyostratigrafik ve Kronostratigrafik ‹ncelenmesi D‹R‹K, K. & EROL, O. 2003. Tectonomorphologic evolution of Tuzgölü [Biostratigraphic and Chronostratigraphic Investigation of and surrounding area, central Anatolia-Turkey. Turkish Ostracoda Assemblage of ‹nsuyu Limestone (Karapınar/Konya)]. Association of Petroleum Geologists, Special Publications 5, MSc Thesis, Hacettepe University [in Turkish with English 27–46 [in Turkish with English abstract]. abstract, unpublished]. D‹R‹K, K. & GÖNCÜO⁄LU, M.C. 1995. Neogene structural features of the BEKTAfl, O., EYÜBO⁄LU, Y. & MADEN, M. 2007. Different modes of stress western part of Tuzgölü, Central Turkey. International Earth transfer in a strike-slip fault zone: an example from the North Sciences Colloquium on the Aegean Region, Abstracts, p. 3. Anatolian Fault System in Turkey. Turkish Journal of Earth D‹R‹K, K. & GÖNCÜO⁄LU, M.C. 1996. Neotectonic characteristics of central Sciences 16, 1–12. Anatolia. International Geology Review 38, 807–817. BOZKURT, E. 2001. Neotectonics of Turkey – a synthesis. Geodinamica ERKÜL, F., HELVACı, C. & SÖZB‹L‹R, H. 2005. Stratigraphy and Acta 14, 3–30. geochronology of the Early Miocene volcanic units in the Bigadiç BOZKURT, E. & MITTWEDE, K.S. 2005. Introduction: Evolution of Neogene borate basin, Western Turkey. Turkish Journal of Earth Sciences extensional tectonics of western Turkey. Geodinamica Acta 18, 14, 227–253. 153–165. EROL, O. 1969. Tuzgölü Havzasının Jeolojisi ve Jeomorfolojisi [Geology ÇEMEN, ‹., GÖNCÜO⁄LU, M.C. & D‹R‹K. 1999. Structural evolution of the and Geomorphology of Tuzgölü Basin]. TÜB‹TAK-MTA Report Tuzgölü basin in Central Anatolia, Turkey. Journal of Geology no. 4220 [in Turkish, unpublished]. 107, 693–706.

491 ‹NÖNÜ-ESK‹ﬁEH‹R FAULT SYSTEM, CENTRAL ANATOLIA

ERSOY, Y. & HELVACı, C. 2007. Stratigraphy and geochemical features of ÖZCAN, A., GÖNCÜO⁄LU, M.C., TURHAN, N., UYSAL, fi. & fiENTÜRK, K. 1990. the Early Miocene bimodal (ultrapotassic and calc-alkaline) Paleozoic evolution of the Kütahya-Bolkarda¤ı Belt. METU volcanic Activity within the NE-trending Selendi Basin, Western Journal of Pure and Applied Sciences 21, 211220. Anatolia, Turkey. Turkish Journal of Earth Sciences 16, ÖZSAYıN, E. & D‹R‹K, K. 2005. Quaternary activity of Cihanbeyli Fault 117–139. Zone (Southern segment of Eskiflehir-Sultanhanı Fault System). th GÖNCÜO⁄LU, M.C., DIRIK, K., ERLER, A., YALıNıZ, K., ÖZGÜL, L. & ÇEMEN, ‹. ATAG-9 Active Tectonic Research Group 9 Meeting. 22-24 1996. Tuzgölü Havzası Batı Kısmının Temel Jeolojik Sorunları September 2005, Abstracts Book, 41. [in Turkish]. [Basic Geologic Problems of Western Part of Tuzgölü Basin] fiARO⁄LU, F., EMRE, Ö. & BORAY, A. 1987. Türkiye’nin Diri Fayları ve Turkish Petroleum Corporation (TPAO) Report no. 3753 [in Depremsellikleri [Seismicity and Active Faults of Turkey]. Mineral Turkish, unpublished]. Research and Exploration Institute (MTA) of Turkey Report no. KAYMAKCı, N., ‹NCEÖZ, M. & ERTEPıNAR, P. 2006. 3D-architecture and 8174 [in Turkish, unpublished]. Neogene evolution of the Malatya basin: inferences for the fiENGÖR, A.M.C., GÖRÜR, N. & fiARO⁄LU, F. 1985. Strike-slip faulting and kinematics of the Malatya and Ovacık fault zones. Turkish Journal related basin formation in zones of tectonic escape: Turkey as a of Earth Sciences 15, 123–154. case study. In: BIDDLE K.T. & CHRISTIE-BLICK, N. (eds), Strike-slip KOÇY‹⁄‹T, A. 1991. Changing stress orientation in progressive Faulting and Basin Formation. The Society of Economic intracontinental deformation as indicated by the neotectonics of Paleontologists and Mineralogists, Special Publications, 37, the Ankara region (NW of Central Anatolia). Association of 227–264. Turkish Petroleum Geologists Bulletin 3, 48–55. TOKCAER, M., AGOSTINI, S. & SAVAfiÇıN, M.Y. 2005. Geotectonic Setting KOÇY‹⁄‹T, A. 2003. General neotectonic characteristics and seismicity of and origin of the youngest Kula volcanics (Western Anatolia), with central Anatolia. Turkish Association of Petroleum Geologist a new emplacement model. Turkish Journal of Earth Sciences 14, Special Publication 5, 1–26 [in Turkish with English abstract]. 143–166.

KOÇY‹⁄‹T, A. 2005. The Denizli graben-horst system and the eastern TUNO⁄LU, C., TEMEL, A. & GENÇO⁄LU, H. 1995, Pliocene ostracoda limit of western Anatolian continental extension: basin fill, association and environmental characteristics of Sivrihisar structure, deformational mode, throw amount and episodic (Eskiﬂehir)-Central Anatolia. In: RIHA, J. (ed), 12th International evolutionary history, SW Turkey. Geodinamica Acta 18, Ostracoda Symposium, Ostracoda and Biostratigraphy. Belkama, 167–208. Rotterdam, 265–275.

KOÇY‹⁄‹T, A. & BEYHAN, A. 1998. A new intracontinental transcurrent ULU, Ü., OCAL, H., BULDUK, A.K., KARAKAfi, M., ARBAS, A., SAÇLı, L, structure: the Central Anatolian fault zone, Turkey. TAfiKıRAN, A., EKMEKÇi, E., ADıR, M., SÖZERi, fi. & KARABıYıKO⁄LU, M. Tectonophysics 284, 317–336. 1994. Late Cenozoic depositional system of the Cihanbeyli – Karapınar region, southern inner Anatolia: tectonic and climatic KOÇY‹⁄‹T, A. & EROL, O. 2001. A tectonic escape structure: Erciyes pull- implications. 9th Geological Congress of Turkey, Abstracts Book, apart basin, Kayseri, central Anatolia, Turkey. Geodinamica Acta 149–163 [in Turkish with English abstract]. 14, 133–145. ÜNALAN, G. & YÜKSEL, V. 1978. Example of an ancient graben: The KOÇY‹⁄‹T, A. & ÖZACAR, A.A. 2003. Extensional neotectonic regime Haymana-Polatlı basin. Bulletin of the Geological Society of through the NE edge of the outer Isparta angle, SW Turkey: new Turkey 21, 165–169. field and seismic data. Turkish Journal of Earth Sciences 12, 67–90. YALTıRAK, C., YALÇıN, T., BOZKURTO⁄LU, E. & YÜCE, G. 2005. Water-Level changes in shallow wells before and after the 1999 ‹zmit and KOÇY‹⁄‹T, A., KAYMAKCı, N., ROJAY, B., ÖZCAN, E., D‹R‹K, K. & ÖZÇEL‹K, Y. Düzce earthquakes and comparison with long-term water-level 1991. ‹negöl-Bozüyük Arasında Kalan Alanın Jeolojik Etüdü observations (1999–2004), NW Turkey. Turkish Journal of Earth [Geologic Investigation of an Area Between ‹negöl-Bozüyük]. Sciences 14, 281–309. Turkish Petroleum Corporation (TPAO) Report no. 3049 [in Turkish, unpublished]. YÜCEL-ÖZTÜRK, Y., HELVACı, C. & SATıR, M. 2005. Genetic relations between skarn mineralization and petrogenesis of the Evciler KOÇY‹⁄‹T, A., ÜNAY, E., SARAÇ, G. 2000. Episodic graben formation and Granitoid, Kazda¤, Çanakkale, Turkey and comparison with world extensional neotectonic regime in west central Anatolia and the skarn granitoids. Turkish Journal of Earth Sciences 14, 255–280. Isparta Angle: a key study in the Akflehir-Afyon graben, Turkey, In: BOZKURT, E., W‹NCHESTER, J.A. & P‹PER, J.D.A. (eds), Tectonics and Magmatism in Turkey and the Surrounding Area. Geological Society of London, Special Publication, 173, 405–421.

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