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Changing stress orientation in progressive intracontinental deformation as indicated by the neotectonics of the Ankara region (NW Central Anatolia)
... tarafından MTA (1989) Şekil 2.1 Tuz Gölü Havzası ve çevresinin neotektonik haritası Göncüoğlu vd. 1996;Koçyiğit 1991;Dirik 2001 (Rigo and Cortesini 1959;Schmidt 1960;Arıkan 1975;Ünalan vd. 1976;Dellaloğlu 1991;Ayyıldız 2000 İlk çalışmalar Şereflikoçhisar civarındaki kömür çalışmalarıyla ilgilidir (Romberg 1937, Wedding 1955, İlhan 1962. ...
... 1988, Gökten ve Kazancı 1988, Gökten vd. 1988, Koçyiğit 1991, Demirel ve Şahbaz 1994, Görür vd 1998. Bunlara ilaveten, Görür vd. ...
... Şekil 2.1 Tuz Gölü Havzası ve çevresinin neotektonik haritası Göncüoğlu vd. 1996;Koçyiğit 1991;Dirik 2001) 20 Şekil 2.2 Çalışma alanına ait genel jeoloji haritası (Sonel vd. 1996'dan değiştirilerek) ...
Master Thesis
DIAGENETIC AND RESERVOIR ROCK PROPERTIES OF THE LATE EOCENE AGED SILICICLASTICS IN THE TUZ GÖLÜ BASIN (AROUND ŞEREFLİKOÇHİSAR)
Yazgan KIRKAYAK
Ankara University
Graduate School of Natural and Applied Sciences
Department of Geological Engineering
Supervisor : Assoc. Prof. Dr. Turhan AYYILIDIZ
The study area is located in the east of the Tuz Gölü Basin, one of the sedimantary basins in the Central Anatolia, between Ş. Koçhisar and Karapınar districts. The objective of this research is siliciclastics of Boyalı Member (Middle-Upper(?) Eocene) of Karapınar formation. The Boyalı Member is composed of thick sandstones and massive conglomerate facies indicating alluvial fan – braided stream delta and submarine fan channel environment. Sandstones, by the petrographic classification, are composition of arkoses to lithic arkose and feldspathic litharenite. Carbonate and FeO2 cements in early diagenesis and dolomite and silica cement were observed in the late diagenesis. Otigenetic chlorit-smectite formation were also determined. Feldspar and carbonate dissolution by solution effect in underground were determined. According to laboratory analysis (33 samples) that porosity and permeability values constitute of this subject are between 1.40 – 19.40% (average 9.15%) and 0.01 – 43.95 mD (average 5.07 mD), respectively. After porosity measuring at laboratory, thin sections were analyzed that made from impregnated blue resin plug. Petrographic photos were taken from the thin sections and pore volumes were calculated from 3D computer program. By using total and pore volume, porosity values of the samples were determined and were averaged. Positive correlation is generally observed between laboratory analysis and visual porosity from thin sections. However, it was determined influence factors that increases differences between 3D visual analysis and laboratory which are grain size, sphericity and micro-porosity parameters and for reduce these difference to minimum some coefficient were determined.
According to laboratory and 3D visual data, it was identified that middle to upper(?) Eocene siliciclastics have fair to good reservoir quality. Early and Late diagenesis structures and textures have been demonstrated. Facies changing from massive sandstone and conglomerate to fine grain deposits along lateral direction and through the basin centre. In this case the Boyalı siliciclastics toward the basin center has shows target risk in the basin.
August 2014, 131 pages
Keywords: Diagenesis, 3D porosity modeling, Tuz Gölü Basin, Karapınar formation, Boyalı member
... (1988)'nin Ankara'nın kuzeybatısında Bağlum ve Kazan arasında gerçekleştirdikleri çalışmaya göre, Oligo-Miyosen ile Pliyosen aralığında daralmalı rejimin etkisindeki bölge, Pliyosen sonrasında graben oluşumu ile temsil olunan genişlemeli bir neotektonik rejimin etkisi altına girer. Bununla birlikte, Koçyiğit (1991) Ankara bölgesinin neotektoniğini incelediği çalışmasında bölgedeki yapıları KB-GD yönlü daralma etkisiyle gelişmiş Geç Pliyosen öncesi ve K-G yönlü daralmanın oluşturduğu Geç Pliyosen-Kuvaterner olarak iki gruba ayırır. Bu çalışmaya göre Geç Miyosen'den beri bölgeyi etkileyen KB-GD yönlü daralma rejimi Geç Pliyosen'de yerini K-G daralmaya bırakır ve günümüzde de etkin olan daralma yönü K-G'dir. ...
... Bu çalışmaya göre Geç Miyosen'den beri bölgeyi etkileyen KB-GD yönlü daralma rejimi Geç Pliyosen'de yerini K-G daralmaya bırakır ve günümüzde de etkin olan daralma yönü K-G'dir. Koçyiğit (1991)'in Ankara çevresinde Yuva Köyü civarı, Yakacık Köyü'nün kuzeydoğusu, Edige Köyü'nün 500 m güneydoğusu ve 2 km kuzeyinde incelediği bölgelerde Neojen öncesi temel birimler ile Neojen birimler arasında bindirme olarak gösterilen sınırlar, Seyitoğlu vd. (1997) tarafından yeniden gözden geçirilerek tartışılmıştır. ...
... Koçyiğit (1992)'in Ankara-Yuva Köyü'ndeki gözlemlerine göre, Ankara-Erzincan Kenet Zonu boyunca çarpışma sonrası daralmalı rejim Ponsiyen (Geç Miyosen)'de sonlanmış ve sonrasında doğrultu atımlı faylanmayla ilişkili Pliyo-Kuvaterner yaşlı neotektonik bir döneme girilmiştir. Yuva Köyü'ndeki fayın türü ile ilgili farklı iki görüş olması nedeniyle (Koçyiğit, 1991;1992;Seyitoğlu vd., 1997Seyitoğlu vd., ) Özsayın vd. (2005 Ankara-Yuva Köyü civarında gerçekleştirdikleri çalışmada, Koçyiğit (1992) tarafından K-G yönlü daralmanın kanıtı olarak gösterilen D-B doğrultulu bindirme faylarının varlığını arazi gözlemleriyle doğrulamıştır. ...
The Neogene and younger sedimentary units, which are located in the W of Ankara, NW central Anatolia, have been uplifted and deformed by the pre-Neogene basement rocks due to the crustal contraction. Thus, a tectonic wedge structure has been formed in cross-section view. This structure having coeval thrust and normal faults at its eastern and western boundaries, respectively, is called as Abdüsselam Pinched Crustal Wedge (APCW). The contraction related deformation structures in the Neogene and younger sedimentary units around the APCW and along its northern and southern continuation show that the NW-SE-directed contractional regime has been active in the region since Middle Pliocene. Therefore, the faults related to the APCW located in the west of Ankara city center should be taken into consideration for the earthquake risk when considering the dense settlement and the other important facilities in the region.
... Then, these geologic units were differentiated according to the physical properties; and maps of these properties were also prepared by site characterization studies obtained from boreholes and geophysical testing studies. Hence, the engineering geological and geotechnical site characterization studies have been compiled; and geophysical site characterization studies have been performed to enable the assessment of local site conditions along the sedimentary deposits of the Ankara basin (Koçkar, 2006). By using all of these studies, a seismic hazard assessment map was developed to summarize the potential for the respective hazards, and to indicate areas that require further detailed investigation within the study area. ...
... This seismic hazard assessment project was conducted as the first prototype study for Ankara (Koçkar, 2006). Ankara, the capital city of Turkey with a population of about 3.69 million and area of approximately 300 km 2 , is located at an intersection point of highways connecting east to west and north to south of Anatolia (Figure 1). ...
... The groundwater level varies within the alluvium and ranges between 2 to 6 m (DSİ, 1975). Generally, the thickness and width of the recent alluvial deposits observed along the Ankara River and its major tributaries relatively range between 5 m and 45 m and from 0.2 to 3 km, respectively (Erol, 1973;DSİ, 1975;Kasapoğlu, 1980;Koçkar, 2006). The study area that lies in the Ankara Region is a broad and structurally triangular area delineated by the right lateral strike-slip fault zone, namely, the Seyfe Fault Zone (SFZ) in the east, the oblique-slip normal fault zone, namely, the Salt Lake Fault Zone (SLFZ) in the southeast and the right lateral strike-slip fault system, namely, the North Anatolian Fault System (NAFS) in the north. ...
The purpose of this study is to assess the in-situ site characteristics and to perform seismic hazard studies of the Upper Pliocene to Pleistocene fluvial and Quaternary alluvial and terrace deposits located towards the west of Ankara. Based on a general engineering geological, geotechnical and seismic characterization of the site, site classification systems were assigned for seismic hazard evaluations. Then, short-period noise recordings of the microtremor measurements at the ground surface have been used to estimate the site response of the site. This research mainly focuses on the development of a methodology to integrate the various components necessary for a regional multi- hazard seismic risk assessment that includes consideration of hazards due to local site effects. These tasks have been fulfilled through the development of an engineering database that was obtained from invasive and non-invasive explorations at the study area. Hence, the engineering geological and geotechnical site characterization studies have been compiled; and geophysical site characterization studies have been performed, particularly in the Quaternary sediments of the Ankara basin. By using all of these studies, hazard assessment maps (i.e., site classification map and site period map) and a seismic zonation map of Ankara basin, Turkey were developed along with discussing the consequences of the seismic hazards.
... Paleosen'de çarpışma ile ilişkili magmatiklerden Orta Anadolu Granitoyidleri olarak adlandırılan plütonik kayalar, temele ait metamorfik birimler ile ofiyolitleri sıcak dokanaklarla kesmişlerdir. Neo-Tetis'in kapanmasına koşut olarak Geç Kretase'den itibaren Sakarya Kıtası ve Kırşehir Bloku olmak üzere iki kıtasal birim üzerinde [8], Orta Anadolu havzaları [9] oluşmaya başlamış ve Orta Miyosen'e kadar gelişimlerini sürdürmüşlerdir. Orta Miyosen'den itibaren ise neotektonik "Ova" rejimi [10] altında intrakratonik havzalar gelişmiş olup [11], bu rejim Geç Pliyosen'e kadar [9] devam etmiştir. ...
... Neo-Tetis'in kapanmasına koşut olarak Geç Kretase'den itibaren Sakarya Kıtası ve Kırşehir Bloku olmak üzere iki kıtasal birim üzerinde [8], Orta Anadolu havzaları [9] oluşmaya başlamış ve Orta Miyosen'e kadar gelişimlerini sürdürmüşlerdir. Orta Miyosen'den itibaren ise neotektonik "Ova" rejimi [10] altında intrakratonik havzalar gelişmiş olup [11], bu rejim Geç Pliyosen'e kadar [9] devam etmiştir. Şekil 1. İnceleme alanının jeoloji haritası ve örnek yerleri [12]. ...
... Paleosen'de çarpışma ile ilişkili magmatiklerden Orta Anadolu Granitoyidleri olarak adlandırılan plütonik kayalar, temele ait metamorfik birimler ile ofiyolitleri sıcak dokanaklarla kesmişlerdir. Neo-Tetis'in kapanmasına koşut olarak Geç Kretase'den itibaren Sakarya Kıtası ve Kırşehir Bloku olmak üzere iki kıtasal birim üzerinde [8], Orta Anadolu havzaları [9] oluşmaya başlamış ve Orta Miyosen'e kadar gelişimlerini sürdürmüşlerdir. Orta Miyosen'den itibaren ise neotektonik "Ova" rejimi [10] altında intrakratonik havzalar gelişmiş olup [11], bu rejim Geç Pliyosen'e kadar [9] devam etmiştir. ...
... Neo-Tetis'in kapanmasına koşut olarak Geç Kretase'den itibaren Sakarya Kıtası ve Kırşehir Bloku olmak üzere iki kıtasal birim üzerinde [8], Orta Anadolu havzaları [9] oluşmaya başlamış ve Orta Miyosen'e kadar gelişimlerini sürdürmüşlerdir. Orta Miyosen'den itibaren ise neotektonik "Ova" rejimi [10] altında intrakratonik havzalar gelişmiş olup [11], bu rejim Geç Pliyosen'e kadar [9] devam etmiştir. Şekil 1. İnceleme alanının jeoloji haritası ve örnek yerleri [12]. ...
Within the scope of this study, it is aimed to determine the potential micronized calcite fields in the Kırşehir region and to bring these fields to industries such as paper, paint, ceramics, plastic, agriculture and livestock in the future. The mineralogical petrographic, geochemical and color analyzes were carried out on samples taken from 7 different regions in the study area. With geochemical analysis, the values of the samples such as CaCO3, SiO2 and Fe2O3, as well as the whiteness degrees were determined as a result of color analysis. According to the results obtained, MK-1, MK-2, MK-3, MK-4, MK-5, MK-6 regions have provided the necessary values for the paint, paper and plastic industry. However, considering the impurities of CaCO3, Fe2O3 and MgO, it has been determined that they are not in the required standards for the ceramic industry. MK-7 region, on the other hand, has been observed to meet the criteria of the agriculture and livestock sector. The MK-7 region, where the regions were evaluated in terms of whiteness values, was found to be suitable only for the agriculture and livestock sector, and it was determined that the other regions met the criteria of the paint, paper, plastic and ceramic sectors.
... The existing studies in Central Anatolia indicate a fairly uniform composition continental crustal structure (e.g., Cambaz and Karabulut, 2010) of some 35 km thickness (Ezen, 1994;Kuleli et al., 2001;Mutlu and Karabulut, 2011), which would have been surprising given its average surface elevation of 1000 m asl, had it not been for the observation that a mantle lithosphere seems missing under it (Gögüş et al., 2017, and the literature cited there). The neotectonic (i.e., since the Burdigalian to Serravallian interval: Ş engör, 1980) nature of the Tuz Gölü Fault has received much closer attention (Lahn, 1948(Lahn, , 1949Ketin, 1968;Koçyigit, 1991;Dirik and Göncüoglu, 1996;Emre et al., 2011aEmre et al., , 2011bAktug et al., 2013;Fernandez-Blanco et al., 2013;Ö zsaym et al., 2013;Ö zsayn et al., 2019;Gökten, 2014a, 2014b;Yıldırım, 2014;Melnick et al., 2017;Krystopowicz et al., 2020), although its general recognition by Kurt Leuchs was delayed as late as 1939. What Leuchs wrote (freely translated by Ş engör) then still stands intact: ...
... The fault is now almost a pure right-lateral strike-slip feature (Fig. 6). Therefore, the oft-repeated claim that the fault is now an extensional structure, an oblique-right-slip normal fault, is clearly erroneous; also erroneous is the shortening across segments of the fault mentioned by Ş engör et al. (1985), (Koçyigit, 1991, Fig. 1) and Aktug et al. (2013, p. 94) in an overall assessment of the strain in Central Anatolia. Yet the presence of numerous normal fault patches along the fault has been repeatedly confirmed by field work. ...
We use GPS and InSAR data to examine the present-day kinematics of the Tuz Gölü Fault Zone with a view to documenting an ‘intra-plate-like’ behaviour within a highly active plate boundary zone. In order to generate the strain rate field of the region, we utilize two different approaches. Both of the approaches reveal that the area has a shear-dominated deformation. Furthermore, we design a simple block model to understand better especially the slip on the Tuz Gölü Fault. The results indicate that the fault behaviour can be explained by right-lateral strike-slip motion. This is in contradiction with the previous interpretations of it displaying normal fault behaviour based on geomorphological observations of limited spatial extent. On the other hand, the present-day kinematics of the fault is not an agreement with the thrust features that are observed around it. We think that the propagation of the rupture of the North Anatolian Fault Zone may have put an end to the thrust regime along the Tuz Gölü Fault at the end of Pliocene. We think that this study may provide guidelines for understanding the origin and behaviour of slowly deforming ‘germanotype’ structures within zones of rapidly deforming ‘alpinotype’ regions.
... Bölgede Neotektonik dönem yapıları üzerinde gerçekleştirilen çalışmalar fazladır (örn. Pasquaré vd., 1988;Dirik & Göncüoğlu, 1996;Koçyiğit, 1991Koçyiğit, ve 2003Kaymakçı vd., 2003;Erturaç & Tüysüz, 2012). ...
... Bu alan içerisindeki en önemli yapısal unsurlar kuzeyde KAFZ'nin orta bölümünden ayrılıp güneye doğru at kuyruğu (horsetail structure) geometrisinde dallanarak gelişen Amasya Makaslama Zonu (AMZ) (Erturaç & Tüysüz, 2012), alanın batısında yaklaşık K-G uzanımlı ve ters bileşenli Çankırı Fayı (ÇaF) (Emre vd. 2011a) ve alanın güney uçundaki en bilinen yapısal süreksizlik olan Tuz Gölü Fayı'dır (TGF) (Koçyiğit, 1991). AMZ ise birbirine paralel/yarı paralel yaklaşık D-B ve KD-GB uzanımlı birçok fay ve fay zonundan oluşur. ...
Kula Volkanitleri (KV), Kula İlçesinin 12 km batısında, Simav ve Gediz Grabenleri’ni birbirinden ayıran D-B uzanımlı horstun üzerinde yer almaktadır. Kula Volkanitleri, Kuvaterner’den tarihsel dönem sonuna kadar aktif olan ve günümüzde inaktif niteliği ile Türkiye’nin en genç volkanik bölgelerinden birini oluşturmaktadır. Menderes Masifi’nin metamorfik temelini, İzmir-Ankara-Erzincan Zonu’nun ofiyolitik melanjına ait birimleri ve Selendi havzasının Miyosen yaşlı gölsel volkanosedimanter istifini uyumsuz üzerlemektedir. Petrografik ve petrokimyasal incelemelere göre Kula lavları; alkali olivinli bazalt, tefrit, az oranda mugearit, hawaiit, potasyumca zengin trakibazalt bileşenleri ile alkali bazalt niteliğindedir. Her ne kadar rift açılımlarında meydana gelen zenginleşmiş manto kökenli yükselmeye bağlı volkanizma olduğu kabul görmüş olsa da, yerleşme mekanizması iyi bilinmemektedir. Bu boşluğu doldur�mak için, Kula Volkanik alanına uzaktan algılama yöntemleri ile birlikte saha ve yapısal tabanlı
çalışmalar yapılmıştır. Araştırmalarımız, Kula volkanitlerinin ilk kez bu çalışmada Kula Fayı
ismi ile tanımlanan, KD-GB uzanımlı doğrultu atımlı fayın çek-ayır benzeri gelişen açılmalı
büklümüne yerleştiğini göstermektedir. Kula Fayı Kuvaterner boyunca K-G açılımına oblik
gelişen kabuksal ölçekli süreksizlik zonu olarak kabul edilmiştir. Bu da, Batı Anadolu Genişleme bölgesinde doğrultu-atımlı fayların düşünülenden daha yoğun olduğunu işaret etmektedir.
... Orta Anadolu bölgesinde genel tektonik rejim "Ova rejimi" olarak tanımlanmıştır [11]- [13]. Bölgedeki aktif faylar farklı araştırmacılar tarafından detaylı olarak incelenmiştir [12], [13], [15]. Bu çalışmada özellikle Ankara ve çevresini etkileyebilecek olan Tuzgölü Fay Zonu [13], [14], [15], [16]; İnönü-Eskişehir Fay Zonu [16], [17]; Kuzey Anadolu Fay Zonu-KAFZ ( [18]- [21] ve KAFZ ile Kırıkkale-Erbaa Fay Zonu arasında kalan kıtasal kama dikkate alınmıştır [22], [23]. ...
... Bölgedeki aktif faylar farklı araştırmacılar tarafından detaylı olarak incelenmiştir [12], [13], [15]. Bu çalışmada özellikle Ankara ve çevresini etkileyebilecek olan Tuzgölü Fay Zonu [13], [14], [15], [16]; İnönü-Eskişehir Fay Zonu [16], [17]; Kuzey Anadolu Fay Zonu-KAFZ ( [18]- [21] ve KAFZ ile Kırıkkale-Erbaa Fay Zonu arasında kalan kıtasal kama dikkate alınmıştır [22], [23]. ...
... The Eskişehir Fault Zone constitutes the western to central part (Altunel & Barka 1998;Ocakoğlu & Açıkalın 2009). The system branches into 3 fault zones at the eastern part, namely the Ilıca, Yeniceoba, and Cihanbeyli fault zones (Koçyiğit 1991;Çemen et al. 1999;Dirik & Erol 2003;Dirik et al. 2005;Koçyiğit 2003;Özsayın & Dirik 2007Özsayın & Dirik , 2011 (Figure 1b). The Sultanhanı Fault Zone constitutes the southeastern part of the İnönü-Eskişehir Fault System (Özsayın & Dirik , 2007(Özsayın & Dirik , 2011. ...
... The sedimentary succession in the Tuz Gölü Basin starts with Upper Cretaceous-Paleocene terrestrial clastics and Eocene marine sediments deposited over a crystalline basement composed of metamorphic rocks and ophiolitic mélange units (Ünalan et al. 1976;Görür & Derman 1978;Dellaloğlu & Aksu 1984;Görür et al. 1984;Duru & Gökçen 1985;Özcan et al. 1989, 1990a, 1990bGöncüoğlu et al. 1991Göncüoğlu et al. , 1992Göncüoğlu et al. , 1996Koçyiğit 1991Koçyiğit , 1992Çemen et al. 1999;Dirik & Erol 2003) (Figure 2 Göncüoğlu et al. 1996). sealed by thin-to medium-bedded evaporites of Oligocene age with an angular unconformity ( Figure 2). ...
The Tuz Gölü Basin is the largest sedimentary depression located at the center of the Central Anatolian Plateau, an extensive, low-relief region with elevations of ca. 1 km located between the Pontide and Tauride mountains. Presently, the basin morphology and sedimentation processes are mainly controlled by the extensional Tuz Gölü Fault Zone in the east and the transtensional İnönü–Eskişehir Fault System in the west. The purpose of this study is to contribute to the understanding of the Plio-Quaternary deformation history and to refine the timing of the latest extensional phase of the Tuz Gölü Basin. Field observations, kinematic analyses, interpretations of seismic reflection lines, and 40Ar/39Ar dating of a key ignimbrite layer suggest that a regional phase of NNW–SSE to NE–SW contraction ended by 6.81 ± 0.24 Ma and was followed by N–S to NE–SW extension during the Pliocene–Quaternary periods.Based on sedimentological and chronostratigraphic markers, the average vertical displacement rates over the past 5 or 3 Ma with respect to the central part of Tuz Gölü Lake are 0.03 to 0.05 mm/year for the fault system at the western flank of the basin and 0.08 to 0.13 mm/year at the eastern flank. Paleo-shorelines of the Tuz Gölü Lake, vestiges of higher lake levels related to Quaternary climate change, are important strain markers and were formed during Last Glacial Maximum conditions as indicated by a radiocarbon age of 21.8 ± 0.4 ka BP obtained from a stromatolitic crust. Geomorphic observations and deformed lacustrine shorelines suggest that the main strand of the Tuz Gölü Fault Zone straddling the foothills of the Şereflikoçhisar–Aksaray range has not been active during the Holocene. Instead, deformation appears to have migrated towards the interior of the basin along an offshore fault that runs immediatelywest of Şereflikoçhisar Peninsula. This basinward migration of deformation is probably associated with various processes acting at the lithospheric scale, such as plateau uplift and/or microplate extrusion.
... Önceki çalışmalarda çarpışma sonra-Levent KARADENiZLi; Gürol SEYİTOĞLU; Gerçek SARAÇ; Nizamettin KAZANCI; Şevket ŞEN; Yavuz HAKYEMEZ ve Didem SAVAŞÇI sı dönemde sıkışmalı veya genişlemeli tektonik rejimin hakim olduğu konusunda farklı iki görüş bulunmaktadır. Bunlardan birincisi; Neotetis kapanması ile ilgili kıtalararası sıkışmanın Geç Pliyosen'e kadar devam ettiğini ve bu dönemi "Ankara Orojenik Fazı" diye adlandırılan görüştür (Koçyiğit, 1991;Koçyiğit ve diğerleri, 1995). Bununla beraber Görür ve diğerleri (1998) Çankırı havzasındaki neotektonik rejimin Orta-Geç Miyosen'de kraton içi havza gelişimi ile başladığını belirtir. ...
... Daha öncede değinildiği gibi Neotektonik döneme ait iki farklı görüş vardır. Bunlardan ilki kıtalarası sıkışmanın Geç Pliyosen'e kadar devam ettiği görüşüdür (Akyürek ve diğerleri, 1980(Akyürek ve diğerleri, ,1982Hakyemez ve diğerleri, 1986;Koçyiğit, 1991;Koçyiğit ve diğerleri, 1995). Diğer görüş ise kıtalarası sıkışmanın, Miyosen başında olasılıkla orojenik çökme nedeni ile genişlemen tektonik rejime döndüğü görüşüdür (Seyitoğlu ve diğerleri, 1997;Görür ve diğerleri, 1998;Kaymakçı, 2000). ...
... Buna göre Yeniceoba kolu sağ yanal doğrultu atımdan normal faya değişen karakterdeyken, Cihanbeyli kolu normal fay karakterindedir (Özsayın ve Dirik, 2007(Özsayın ve Dirik, , 2011. Kuzeyde yer alan Ilıca kolu derelerdeki sağ yönlü ötelenmelerin yardımıyla belirlenmiş ve haritalarda gösterilmiştir (Koçyiğit, 1991b;Dirik ve Erol, 2003). Bununla birlikte yapısal ve jeomorfolojik özellikleri detaylı olarak çalışılmamıştır. ...
... Uydu görüntülerinde belirgin olan bu makaslama kırıkları sağ yönlü makaslama hareketi ile uyumludur (Şekil 2). Bölgede sıcak su kaynaklarının bulunuşu (Şekil 1b), Koçyiğit (1991b) Şekil 4-Eş-rezistivite kesitleri. Kesitlerin yerleri için şekil 1b'ye bakınız. ...
Eskişehir Fay Zonu Türkiye’nin önemli neotektonik
yapılarından biridir. Anadolu bloğunda yer alan Batı Anadolu genişleme bölgesi
ile doğrultu atımlı fay etkisi altındaki kuzeybatı Orta Anadolu daralma
bölgesini birbirinden ayırır. Eskişehir Fay Zonu’nun güneydoğu bölümü genel
olarak kuzeyden güneye sırasıyla Ilıca, Yeniceoba ve Cihanbeyli ismini taşıyan
üç bölüme ayrılır. Sağ yanal doğrultu atımlı Ilıca kolu yaklaşık 100 km
uzunluğundadır ve kuzeybatı-güneydoğu doğrultusunda birçok parçadan oluşur. Fay
yüzeyleri, ikincil kırıklar, kataklastik zon, kırık kontrollü drenaj yapısı,
sağ yanal dere ötelenmeleri, Kuvaterner birim içinde sismik yansıma
kesitlerinde gözlenen deformasyon ve bölgenin depremselliği Ilıca kolunun sağ
yanal doğrultu atımlı aktif bir fay olduğunu göstermektedir. Ilıca kolunun
Ankara’nın batı-güneybatısındaki daralmayla ilişkili yapıları güneyden
sınırlandırdığı düşünüldüğünde, Orta Anadolu’daki daralmalı ve genişlemeli
bölgeler arasında bir sınır fayı olarak ayrıca bölgesel tektonik anlamda bir
önemi vardır.
... Orta Anadolu "ova" bölgesi, bu sistemlerin ortasındaki geçiş zonunu oluşturmaktadır (Dirik ve Göncüoğlu, 1996;Koçyiğit ve Beyhan, 1998;Dirik, 2001;Koçyiğit ve Erol, 2001;Dirik ve Erol, 2003;Koçyiğit ve Özacar, 2003;Koçyiğit, 2005 (Koçyiğit, 1991b(Koçyiğit, , 2005Çemen vd., 1999;Dirik ve Erol, 2003;Dirik vd., 2005) Şekil 3.3. Orta Anadolu ve çevresinin tektonik haritası (Dirik ve Erol, 2003;Dirik, 2001;Dirik ve Göncüoğlu, 1996;Göncüoğlu vd., 1996; Özacar, 2003'ten değiştirilerek alınmıştır). ...
... Ilıca fay zonu sistemin bu bölümünün en kuzeyinde kalan bölümüdür. İlk olarak Koçyiğit (1991b) ...
The İnönü-Eskişehir Fault System is one of the most important fault systems in
Central Anatolia and composed of series of NW–SE-to WNW–ESE trending fault
zones, extending from Uludağ (Bursa) in the northwest to Sultanhanı in the
southeast. Eskişehir fault zone is the western branch of this system where Ilıca,
Yeniceoba, Cihanbeyli and Sultanhanı fault zones are the eastern branches from
Sivrihisar to the east. Neotectonic characteristics, evolution and seismicity of the
Cihanbeyli and eastern part of Yeniceoba fault zones form the main subject of this
research.
Rock units experiencing in the study area are divided into two main groups:
basement and cover rocks. Kütahya-Bolkardağı Metamorphics and Central
Anatolian Ophiolitic Melánge form the basement rocks. They are unconformably
overlain by Upper Cretaceous–Middle Paleocene terrestrial Kartal and Paleocene–
Lower Eocene shallow marine Çaldağ formations. Oligo–Miocene terrestrial
Gökdağ Formation overlies the other basement rocks with an angular
unconformity. Cover units commence with Pliocene lacustrine Cihanbeyli and
Pleistocene terrestrial Tuzgölü formations that covers older basement rocks with
an angular unconformity. These units are overlain by recent deposits. Alluvial fans,
talus, alluvium, sodium sulphate deposits around Bolluk Lake and travertine cones
are examples of recent deposits.
NW–SE-trending Cihanbeyli fault zone comprises south-dipping fault planes and is
well exposed between Sülüklü in the west and Cihanbeyli in the east. Different
segments of the Cihanbeyli fault zone affects the sediments of Gökdağ and
Cihanbeyli formations, as well as the alluvial deposits, attesting their activity. The
detailed fault plane data and their kinematic analysis are consistent with normal
faulting.
vii
Yeniceoba fault zone lies between Günyüzü in the west and Yeniceoba in the
east. It is composed of NW–SE-trending and north-dipping fault segments which
cut both the basement and the cover rocks. Along this fault zone, two
superimposed sets of slickenlines indicate an early phase of pure right-lateral
strike-slip faulting and a normal faulting with minor right lateral component.
The NW–SE-trending ridge between the two fault zones is named as Kelhasan
horst; Kuşça half graben, bounded by a fault which branches off the Yeniceoba
fault zone, is also located along the fault zone. Cihanbeyli graben bounded by the
Kelhasan horst lies at the eastern part of the Cihanbeyli fault zone.
The kinematic analyses of fault-slip data clearly indicate that the area has been
experiencing an extensional deformation in NNE–SSW direction. The recent
horizontal terrace deposits cut by series of steeply-dipping normal faults with minor
strike-slip component, which are located on Yeniceoba and Cihanbeyli fault zones,
indicate the activity of both fault zones during the Quaternary under the control of
NNE–SSW directed extension.
Extension direction obtained from kinematic analysis, presence of recent faulting
located only at the eastern and sourtheastern part of the study area which are the
indicators of active extension, trends and geometry of the faults clearly show that
the southeastern part of the study area is more widen than nortwestern. This
situation is the reason of the Isparta Angle and results with counter-clockwise
rotation of the northeastern area. Eastern extensions of Yeniceoba and Cihanbeyli
fault zones are controlled by Altınekin fault zone which is considered to be an
accomodation fault.
The distribution of the earthquake epicenters along various segments attest the
recent activity of the fault zone.
... The Yeniceoba and Cihanbeyli branches (Çemen et al., 1999) have been investigated in detail by Özsayin and Dirik (2007), who concluded that the characteristics of the Yeniceoba branch vary from the right lateral strikeslip to the normal fault, while the Cihanbeyli branch has a normal fault character Dirik, 2007, 2011). The northern Ilica branch appears on the maps (Koçyiğit, 1991b;Dirik and Erol, 2003) and has been drawn with the help of the right lateral displacements of the streams. However, its structural and geomorphological features have not been studied in detail. ...
... Mesozoic limestone in this area is highly fractured; these shear fractures are concurrent with the right lateral sense of shear that is apparent in the satellite images ( Figure 2). The hot spring occurrences ( Figure 1b) are one of the indicators of the fault activity in the area as also mentioned by Koçyiğit (1991b). ...
Eskişehir Fay Zonu Türkiye’nin önemli neotektonik yapılarından biridir. Anadolu bloğunda yer alan Batı Anadolu genişleme bölgesi ile doğrultu atımlı fay etkisi altındaki kuzeybatı Orta Anadolu daralma bölgesini birbirinden ayırır. Eskişehir Fay Zonu’nun güneydoğu bölümü genel olarak kuzeyden güneye sırasıyla Ilıca, Yeniceoba ve Cihanbeyli ismini taşıyan üç bölüme ayrılır. Sağ yanal doğrultu atımlı Ilıca kolu yaklaşık 100 km uzunluğundadır ve kuzeybatı-güneydoğu doğrultusunda birçok parçadan oluşur. Fay yüzeyleri, ikincil kırıklar, kataklastik zon, kırık kontrollü drenaj yapısı, sağ yanal dere ötelenmeleri, Kuvaterner birim içinde sismik yansıma kesitlerinde gözlenen deformasyon ve bölgenin depremselliği Ilıca kolunun sağ yanal doğrultu atımlı aktif bir fay olduğunu göstermektedir. Ilıca kolunun Ankara’nın batı-güneybatısındaki daralmayla ilişkili yapıları güneyden sınırlandırdığı düşünüldüğünde, Orta Anadolu’daki daralmalı ve genişlemeli bölgeler arasında bir sınır fayı olarak ayrıca bölgesel tektonik anlamda bir önemi vardır.
The Eskişehir Fault Zone is one of the prominent neotectonic structures of Turkey. It separates the west Anatolian extensional province and the strike-slip induced northwest central Anatolian contractional area in the Anatolian Block. Its southeastern part is generally divided into three branches, namely the Ilıca, Yeniceoba, and Cihanbeyli from north to south, respectively. The right lateral strike-slip Ilıca branch (IB) is an approximately 100-km-long fault and it is composed of several segments in a northwest-southeast direction. The slickensides, subsidiary fractures, cataclastic zone, fracture-controlled drainage pattern, right lateral stream deflections, deformation in the Quaternary unit observing in the seismic reflection sections, and seismicity of the region all indicate that the IB is an active right lateral strike-slip fault. The IB has also a regional tectonic importance as a boundary fault between the contractional and the extensional regions in central Anatolia considering that it is the southern limit of the contraction-related structures in the west-southwest of Ankara.
... 4. The cumulative rotations determined from paleomagnetism are in any case unlikely to have resulted from a uniform stress regime of long continuity, because progressive clockwise rotation of the regional stress field appears to have occurred across Anatolia since Pliocene times. This is evident, for example, in the Ankara area, where regional compression moved from northwest-southeast before late Pliocene times to north-south during Pleistocene times (Koçyigit, 1991), and in western Anatolia, where regional extension moved from north-south to northeast-southwest over broadly the same period (Glover and Robertson, 1998). 5. Magnetic directions have rotated across the area of Anatolia in the way predicted from westward extrusion of an upper brittle crust to the west and south by the indentation of Arabia in the east (Fig.7). While the limitations of modeling mean that the character of this distributed deformation is not well reproduced in small-scale experiments (Hubert-Ferrari et al., 2003), it is expected from the temporal changes in the tectonic regimes (Koçyigit, 1991;Westaway, 2003) and from the presence of numerous crustal dislocations, such as terrane boundaries inherited from the paleotectonic collisional history. ...
... This is evident, for example, in the Ankara area, where regional compression moved from northwest-southeast before late Pliocene times to north-south during Pleistocene times (Koçyigit, 1991), and in western Anatolia, where regional extension moved from north-south to northeast-southwest over broadly the same period (Glover and Robertson, 1998). 5. Magnetic directions have rotated across the area of Anatolia in the way predicted from westward extrusion of an upper brittle crust to the west and south by the indentation of Arabia in the east (Fig.7). While the limitations of modeling mean that the character of this distributed deformation is not well reproduced in small-scale experiments (Hubert-Ferrari et al., 2003), it is expected from the temporal changes in the tectonic regimes (Koçyigit, 1991;Westaway, 2003) and from the presence of numerous crustal dislocations, such as terrane boundaries inherited from the paleotectonic collisional history. ...
Closure of the Neo-Tethyan Ocean in the Turkish sector of the Alpine-Himalayan orogen by ca. 12 Ma was succeeded by deformation of a domain between the Eurasia plate, presently bounded by the North Anatolian fault, and the Arabian indenter. Facets of this deformation comprise the crustal thickening and uplift that produced the Anatolian plateau, the establishment of transform faults, and tectonic escape as Arabia has continued to impinge into the collage of Anatolian terranes accreted by closure of the Neo-Tethys. We have compiled a database of neotectonic paleomagnetic results from Anatolia to analyze this deformation. Large rotations (up to 5 degrees/10,000 yr) of small fault blocks along the intracontinental transform faults but do not extend away from these zones and show that seismogenic upper crust is decoupled from lower continental lithosphere undergoing continuum deformation. Between the transforms, large fault blocks exhibit slower rotation rates (mostly < 1 degrees/100,000 yr), varying systematically across Anatolia. Large counterclockwise rotations near the Arabian indenter diminish westward, becoming zero, and then move clockwise near the limit of tectonic escape. The view that the collage has rotated counterclockwise as a single plate, either uniformly or episodically, during the Neotectonic era is refuted. Instead, deformation has been distributed and differential as the collage adapted to changing tectonic regimes. Crustal extrusion to the west and south has expanded the curvature of the Tauride arc and combined with back-roll on the Hellenic arc to produce the extensional horst and graben province in western Turkey. The latitudinal motions are close to confidence limits but consistent with similar to 800 km of northward motion of Anatolian terranes over 40 m.y., a figure including up to a few hundred kilometers of closure linked to crustal thickening since the demise of the Neo-Tethys.
... Southeast of the Çift eler-Mahmudiye-Emirdağ basin, the Yeniceoba and Cihanbeyli fault zones run parallel to the general trend of the İnönü-Eskişehir Fault System. In general, on earlier neotectonic maps of the region, the Yeniceoba and Cihanbeyli fault zones are shown to be the eastward continuation of the İnönü-Eskişehir Fault Zone (Koçyiğit 1991;Koçyiğit et al. 1995;Dirik & Göncüoğlu 1996;Dirik 2001;Dirik & Erol 2003;Koçyiğit & Özacar 2003). However, we observed that the Yeniceoba and the Cihanbeyli fault zones are located further south and are connected to the İnonü-Eskişehir Fault Zone by an intervening transfer fault trending NNW-SSE along the Çıralıözü creek to the east of the study area, as seen in the Ankara sheet of the 1/500,000 scale geological map of Turkey (Erentöz 1963). ...
... In general, the long axis of this parallelogram-shaped basin extends NE-SW. Th e Yeniceoba and the Cihanbeyli fault zones are shown to be the southeastern continuation of the İEFS on the previous neotectonic map of the region (Dirik 1991;Koçyiğit 1991;Koçyiğit et al. 1995;Dirik & Göncüoğlu 1996;Dirik & Erol 2003;Koçyiğit & Özacar 2003). However, these two fault zones are connected to the EFZ by an intervening and NNW-SSE-trending transverse structure in the far east of the study area, and thus they only indirectly aff ect the southeast section of the Mahmudiye-Çift eler-Emirdağ basin ( Figure 20). ...
The İnönü-Eskişehir Fault System (İEFS) is a NW- to WNW-trending zone of active deformation about 15-25 km wide, 400 km long and characterized predominatly by strike-slip faulting. In this study, the Yörükkaracaören (SE of Eskişehir)-Sivrihisar section of the İEFS was investigated. The system consists of three fault zones, namely the Alpu Fault Zone (AFZ), the Eskişehir Fault Zone (EFZ) and the Orhaniye Fault Zone (OFZ) in the study area. The EFZ is made up mostly of N30°W-trending right-lateral strike-slip fault segments with normal components. However, the AFZ and OFZ are composed of E-W-trending normal and NE- to NW-trending strike-slip fault segments. The Mahmudiye-Çift eler-Emirdaǧ basin is one of several strike-slip pull-apart basins along the İnönü-Eskişehir Fault System. It is an actively-subsiding NW-trending depression about 25 km wide, 85 km long located between Yörükkaracaören and Emirdaǧ. It contains two infillls. The older and deformed (tilted and folded) infilll, which rests with angular unconformity on the erosional surfaces of pre-Miocene metamorphic and non-metamorphic rocks, consists predominatly of lacustrine carbonates. The younger and undeformed basin infilll (neotectonic infilll) is composed of upper Pliocene-Holocene terrace deposits, alternations of sandstones, lacustrine mudstone to thin limestones and alluvial fans. The two basin infillls separated by an angular unconformity, the deformation pattern of the older basin infilll and the active bounding strike-slip faults all indicate the superimposed character of the Mahmudiye-Çift eler-Emirdaǧ pull-apart basin.
... Sakarya Nehri drenaj sisteminin yaşına ilişkin veriler (Doğan vd., 2019;Altıparmak, 2022) ve diğer bölgesel çalışmalar (Tekin vd. 2008;Şentürk vd (Seyitoğlu vd., 1997;Gökten vd., 1988Gökten vd., , 1996Koçyiğit, 1991Koçyiğit, , 1992Kavuşan 1993;Koçyiğit vd., 1995;Kaymakçı vd., 2001;Yürür vd., 2002;Rojay ve Karaca, 2008;Esat, 2011;Esat vd., 2017;Şahin vd., 2019). Bu çalışmaların bir kısmında Neotektonik dönemde Pliyo-Kuvaterner'de sıkışma rejiminin etkili olduğu, bu dönem öncesinde, zamanları kısmen değişmekle birlikte, bir genişleme rejiminin etkili olduğu belirtilmiştir (Seyitoğlu vd., 1997;Kaymakçı vd., 2001;Yürür vd., 2002;Esat vd., 2017). ...
Kirmir Çayı orojenik İç Anadolu Platosu’nun batı kısmının sularını toplayan Sakarya Nehri’nin bir koludur. Kaynağını Kızılcahamam yakınlarından alan Kirmir Çayı, Beypazarı’nın güneybatısında Sakarya Nehri’ne dahil olur. Kırbaşı Platosunun kuzeyinde yaklaşık olarak D-B uzanışlı olan Kirmir vadisi faylar tarafından kontrol edilmektedir. Bu faylar vadinin asimetrik olmasında ve bazı seki basamaklarının morfolojisi üzerinde önemli bir pay sahibidir. Kirmir Çayı vadisinde yaptığımız araştırmada eski alüvyon deposu korunmuş olan 23 seki basamağı saptanmıştır. Bu sekiler vadi yamaçlarında güncel nehir seviyesinden 5 m (T1) ile 187 m (T23) arasında değişen seviyelerde dağılış gösterir. Sekiler henüz tarihlendirilmemiş olmakla birlikte Kirmir Çayı’nın, Sakarya Nehri ile eş zamanlı olarak vadisini son 4 My’da yaklaşık 700 m kazdığı ve bu sekilerin orta-geç Pleyistosen yaşında oldukları söylenebilir. Bu veri aynı zamanda çalışma alanının İç Anadolu Platosunun orta ve güney kesimlerine göre hızlı bir bölgesel yükselmenin etkisinde kaldığını gösterir
... Koçkar (2006)'a göre Üst Pliyosen-Pleyistosen akarsu tortulları çalışma alanında çok yaygındır ve Sincan, Etimesgut, Batıkent, Demetevler, Yenimahalle, Atatürk Orman Çiftliği, Bahçelievler, Anıttepe, Emek, Yenişehir, ODTÜ, Balgat ve Beytepe'yi kapsayan bölgedeki gibi fay kontrollü havzada çökelmiştir. 'Ankara Kili Formasyonu' da denilen Üst Pliyosen-Pleyistosen akarsu tortulları daha yaşlı, yüksek eğimli ve fazla deforme olmuş temel kayaların düzensiz erozyonlu yüzeyi üzerinde uyumsuz olarak yer alırken; Kuvaterner yaşlı alüvyon veya taraça tortullarınca örtülmekte veya nadiren, daha yaşlı birimlerce bindirilmektedir (Koçyiğit, 1991). Üst Pliyosen-Pleyistosen yaşlı gölsel kireçtaşı üzerinde, eski taraça özelliğinde, konglomera, kumtaşı ve silttaşından oluşan, çapraz tabakalı tortullar da görülmektedir. ...
Günümüzde doğal kaynaklı sismik yer araştırma yöntemleri kolay ölçü alımı ve veri-analizi nedeniyle, mikro bölgeleme çalışmalarında tercih edilen bir yöntemdir. Ankara Kentinin batısında yapılaşma için yoğun olarak tercih edilen Yenimahalle, Etimesgut ve Sincan ilçelerini kapsayan bölgede Ankara Çayı’nın yatağını oluşturan Kuvaterner yaşlı tortulun kalınlığını, makaslama dalgası hızının derinliğe bağlı değişimini ve rezonans frekansını belirlemek üzere 18 farklı noktada Genişletilmiş Uzamsal Öz İlişki yöntemi ile veri toplanmıştır. Elde edilen sonuçlar; Ankara Çayı tortullarının oluşturduğu Kuvaterner birimin sanılandan daha kalın ve değişken geometrili olduğuna, uluslararası yapı kodlarında ve yönetmeliklerde yer alan ve jeoteknik mühendisliğinde yaygın kullanılan Vs30 değerinin bu tür bölgeler için yeterli olamayacağına işaret etmektedir.
... 1984, Ercan 1986, Pasquare vd. 1988, Koçyiğit 1991, Toprak ve Göncüoğlu 1993, Dirik ve Göncüoğlu 1996, Koçyiğit ve Beyhan 1998Gürsoy vd. 1998Gürsoy vd. ...
The Tuz Gölü Fault Zone (TGFZ) is one of the most important active fault zones in Central Anatolia, Turkey. TGFZ is an approximately 200 km-long, 2-25-km wide, NW trending, active, blique normal fault zone. It is located between north of Tuzgölü to the northwest and Kemerhisar (Niğde) town to the southeast. The aim of this study was to investigate the neotectonic and paleoseismological features of TGFZ.
As a result of geological mapping studies, the beginning of neotectonic period for TGFZ region was determined as Pliocene. The amount of cumulative normal dip-slip of TGFZ was measured as 230-290 m since Pliocene. According to the geological age and amount of normal dip-slip, geological slip rate is 0,052 mm-year. The kinematic analyses of fault-slip data clearly indicate that the extensional tectonic regime in the direction of NE-SW was effective on the region since Pliocene. TGFZ was determined to be consisted of nine fault segments according to the structural observations and active fault mapping studies. The length of these fault segments differ from 9 to 30 km. Tuz Gölü and Akhisar-Kılıç segments are the most important segments of TGFZ with their lengths of 30 and 27 km respectivetely, in terms of geological fault length and morphotectonic features. Four paleoseismic events were described on Tuz Gölü segment by
14-
C datings during in the last 31000 years. The earthquake reccurrence interval of Tuz Gölü segment was estimated as 8980 years and elapse time was found as 4010 years. The slip rate of Tuz Gölü segment was estimated as 0,050 mm-year and this value was found to be in consistent with geological slip rate. Three paleoseismic events were described on Akhisar-Kılıç segment by 14-C datings during in the last 23000 years. The earthquake reccurrence interval of this segment was estimated 10390 years and elapse time was found as 2340 years. In this thesis, a new photographic method is suggested to be used for paleoseismological trench studies and this method is named “Paleoseismological Three Dimensional Virtual Photography Method”. This method has been applied for the first time in the paleoseismological study conducted on the TGFZ (Central Anatolia, Turkey).
2012, 289 pages
Key words: Tuz Gölü Fault Zone, Paleoseismology, Neotectonic, Central Anatolia, Paleoseismological Trenching, Radiocarbon (14C), Paleoseismological Three-Dimensional Virtual Photography Method
... The northern section of the basin is underlain by Upper Miocene-Lower Pliocene volcanics and fluvial-lacustrine clastic rocks and the western section is underlain by the Jurassic-Cretaceous carbonates (Koçyigȋt & Türkmenoglu, 1991). The clay-bearing fluvial clastic rocks of the Ankara basin are referred to as the Yalıncak formation (Koçyigȋt, 1991). The generalized geology and the stratigraphy of the region are presented in Figs 2 and 3, respectively. ...
Because of the current need for new landfill sites in Ankara, the suitability of Ankara
Clay as a liner material for landfill sites was investigated. A mineralogical and geotechnical database was
created by compiling the results of previous tests by the present authors as well as those of tests performed
in the present study. The mineralogical properties of the samples were investigated by X-ray diffraction,
scanning electron microscopy and methylene blue adsorption. The cation exchange capacities (CEC) of
the samples vary from 12 to 35 meq/100 g soil and the dominant clay minerals are illite, smectite and
kaolinite. The geotechnical properties of the Ankara Clay samples that were assessed included specific
gravity, the Atterberg limits ( plastic limit, liquid limit, plasticity index), particle-size distribution,
compaction properties (i.e. maximum dry density and optimum water content) and hydraulic
conductivity. Because the hydraulic conductivity of the samples was lower than the acceptable limit of
1 × 10−9 m/s, it follows that, from a geotechnical perspective, Ankara Clay is a suitable material for use as
a compacted clay landfill liner. The relationships between the mineralogical and geotechnical parameters
that were investigated by regression analysis indicated that the hydraulic conductivity of the compacted
soil samples decreased with increasing plasticity index, clay content, CEC, smectite content, smectite to
illite ratio and decreasing illite content. According to the specifications for field construction of
compacted clay liners, Ankara Clay is suitable for compaction in the field.
... A dextral strike-slip fault was observed along the granite-marble contact close to the study area around 10 km southeast (Kaymaz, north of Karakaya village). This fault is named as the Eskisehir fault zone [22] (Figure 1). The analysis of fault slip data shows a NW-SE compression and NE-SW extension in the region. ...
... A dextral strike-slip fault was observed along the granite-marble contact close to the study area around 10 km southeast (Kaymaz, north of Karakaya village). This fault is named as the Eskisehir fault zone [22] (Figure 1). The analysis of fault slip data shows a NW-SE compression and NE-SW extension in the region. ...
The thermal fluids vented over Eskisehir province have been investigated for their origin and to estimate the geothermal potential of the area. Thermal waters as well as bubbling and dissolved gases were collected and analysed for their chemical and isotopic features. Their isotopic composition varies in the range from −11.5 to −7.7 ‰ for δ 18 O, −84 and −57 ‰ for δ 2 H, and 0–7.2 TU for tritium. The gases (bubbling and dissolved) are mostly N 2-dominated with a significant amount of CO 2. The helium isotopic ratios are in the range of 0.2–0.66 R/Rac, indicate remarkable mantle-He contribution ranging between 2 and 10 % in the whole study area. Considering the estimated geothermal gradient about three times higher than the normal gradient, and the reservoir temperatures estimated to be between 50 and 100 °C using quartz and chalcedony geothermometers, a circulation model was built where possible mixing with shallow waters cool down the uprising geothermal fluids. ARTICLE HISTORY
... The N-S trending, approximately 150 km wide and 250 km long Ankara region includes various earthquake centers related to the northern and southern Anatolian ranges and faults (Koçyigit 1991;Fig. 3). ...
Engineering geological and geotechnical sitecharacteristics were assessed and seismic hazard studies performed for the Upper Pliocene to Pleistocene fluvial and Quaternary alluvial and terrace deposits for a site west of Ankara, Turkey. Sediment conditions were determined anda soil profile was characterized by surface geophysical methods. These studies were integrated with existing in-situ characterization studies to create a seismic and geo-technical database for the site. A seismic zonation map of the site was then prepared. Site classification systems were assigned to account for site effects in relation to seismic hazard assessments. The consequences of the seismic hazards were investigated and recommendations were presented.
... Although our findings and observations in the Ecemiş Fault Zone are very local, taken together with other observations of first-order tectonic structures in Central Anatolia [Erol, 1969;Görür et al., 1984;Yetiş and Demirkol, 1984;Koçyiğit, 1991;Dirik and Göncüoğlu, 1996;Koçyiğit and Beyhan, 1998;Çemen et al., 1999; Koçyiğit et al., , 2001Jaffey and Robertson, 2001;Dirik and Erol, 2003;Koçyiğit, 2003;Özsayın and Dirik, 2007;Ocakoğlu and Açıkalın, 2009;Özsayın and Dirik, 2011;Doğan, 2011;Fernández-Blanco et al., 2013;Genç and Yürür, 2010;Kürçer and Gökten, 2012;Yildirim, 2014;Çiner et al., 2015;Gürbüz and Kazancı, 2015] and the Taurides, [Cosentino et al., 2012;Schildgen et al., 2012aSchildgen et al., , 2012bSchildgen et al., , 2014, they contribute to some regional implications. In the interior of Central Anatolia, structural and GPS data reveal predominantly extension with localized strike-slip faulting during the Quaternary [Şengör et al., 1985;Çemen et al., 1999;Jaffey and Robertson, 2001;Özsayın and Dirik, 2007;Ocakoğlu and Açıkalın, 2009;Genç and Yürür, 2010;Doğan, 2011;Kürçer and Gökten, 2012;Özsayın et al., 2013;Aktuğ et al., 2013;Gürbüz and Kazancı, 2015], in agreement with our observations. ...
Here we documented the vertical displacement, slip rate, extension rate, and geochronology of normal faults within a narrow strip along the main strand of the Ecemiş Fault Zone. The Kartal, Cevizlik, and Lorut Faults are normal faults that have evident surface expression within the strip. Terrestrial cosmogenic nuclide geochronology revealed that the Kartal Fault deformed the 104.2±16.5ka aged alluvial fan surface and the Cevizlik Fault deformed the 21.9±1.8ka old moraine and talus fan surfaces. Our topographic surveys indicated 120±10m and 13.1±1.4m surface-breaking vertical displacements along the Kartal and Cevizlik Faults, respectively. Accordingly, we suggest a 1.15±0.21mm a-1 slip rate and 0.66±0.12mm a-1 extension rate for the last 104.2±16.5ka on the Kartal Fault, and a 0.60±0.08mm a-1 slip rate and 0.35±0.05mm a-1 extension rate for the last 21.9±1.8ka on the Cevizlik Fault. We believe that these structures are an integral part of intraplate crustal deformation in the Central Anatolia. They imply that intraplate structures such as the Ecemiş Fault Zone may change their mode through time; presently, the Ecemiş Fault Zone has been deformed predominantly by normal faults. The presence of steep preserved fault scarps along the Kartal, Cevizlik, and Lorut Faults point to surface-breaking normal faulting away from the main strand and particularly signify that these structures need to be taken into account for regional seismic hazard assessments.
... Further studies on the Tertiary geology and stratigraphy were conducted by Birgili et al. (1975), Akyürek et al. (1982), Yoldaş (1982), and Hakyemez et al. (1986). Koçyigit (1991) explained that compressive regime continued until the Late Pliocene in the basin. Tüysüz and Dellaloglu (1994) asserted that in Central Anatolia, the paleogeographic evolution of Ç ankırı Basin and its surrounding during Tertiary was controlled by a compressive regime which gave rise to the closure of the Neotethys Ocean and continued after this closure as well. ...
Bloedite (Na2Mg(SO4)2·4H2O), which is a sodium-magnesium sulfate mineral, has been determined for the first time in Turkey, in the İshaklı Lake within the Çankırı-Çorum Basin. The İshaklı Lake is a seasonal playa lake which is an east–west extending lake with an area of 0.22 km2. Geochemical analyses (XRD, XRF, SEM) of the mineral crust samples indicate that they are composed chiefly of bloedite and thenardite (Na2SO4) minerals and lesser amounts of halite (NaCl) and gypsum (CaSO4·2H2O). In the blodite-thenardite association, thenardite mineral grows on bloedite crystals and it is crystallized after bloedite. The well and the spring (and fountain) waters in the vicinity of the lake are saturated with respect to calcite, dolomite, aragonite and talc minerals. In the waters of the İshaklı Lake, however, the degree of saturation of these minerals gradually increases and they become saturated with respect to anhydrite and gypsum as well. Lake waters represent a hydrochemical facies of Na–Mg–SO4–Cl (type I). Tritium data (3H) indicate that lake waters have higher tritium content (7.55 TU) than the springs and fountains (5.45–6.15 TU), and although there is a thick rock-salt drilled at the bottom of lake (to a depth of 220 m), no recent halite precipitation is observed in the lake bottom. This is attributed to recent recharge and the absence of deep groundwater circulation. The δ18O–δ2H data show that spring and fountain waters are in shallow circulation and have undergone a slight evaporation while waters of İshaklı Lake experienced an intense evaporation. According to Mineral Formation Model proposed herein, a portion of the rainfall reaches directly the lake. Additionally, there is recharge from springs, which travel through the Bozkır Formation and reach the lake. During hot periods, evaporation process begins with carbonate and gypsum precipitation as a white-colored crust on the mud flat along the shore of the lake. Therefore, calcium deficit occurs in the lake water. Further evaporation and possible cation exchange process in clay and muds at the lake bottom might be responsible for the formation of Na-sulfate (bloedite + thenardite) mineralization.
... The N-S trending, approximately 150 km wide and 250 km long Ankara region includes various earthquake centers related to the northern and southern Anatolian ranges and faults (Koçyigit 1991;Fig. 3). ...
... These structures first trend E-W for about 40 km distance, and then bend SW, and run in this direction for several hundreds kilometres by traversing and deforming internally the Anatolian microplate (Koçyiğit & Beyhan 1998, Koçyiğit et al. 2001b). Well-defined examples of splay structures are theOvacık-Malatya, Yakapınar-Yazyurdu, CentralAnatolian, Almus, Yağmurlu-Ezinepazarı or " Sungurlu " and the Laçin fault zones or splay fault zones (Koçyiğit 1998Koçyiğit , 1990Koçyiğit ,1991aKoçyiğit , 1991bKoçyiğit , 1996Şengör & Barka 1992, Özçelik 1994, Kaymakçı & Koçyiğit 1995, Bozkurt & Koçyiğit 1996, Koçyiğit & Beyhan 1998, Kaymakçı 2000, Koçyiğit et al. 2001b). In the second pattern or geometry of the NAFS, the master strand first bifurcates into several fault zones, sub-fault zones, fault sets and isolated faults of varying sizes, and they rejoin and re-bifurcate several times leaving behind a series of lensoidal highlands (pressure ridges or push-ups) such as the Armutlu, Almacık, Sakarya, Hendek, Boludağları, Arkotdağ, Ilgazdağ and Karadağ blocks, and lowlands or depressions (sag-ponds and strike-slip basins) with long axes paralleling to the general trend of the NAFS (Koçyiğit 1989, Koçyiğit et al. 2001c). ...
... As in other central Anatolian basins, the basin principally developed under the control of the north branch of Neo-Tethys since the early Tertiary. Central Anatolian Basins including the Sivas Basin (Koçyiğit 1991;Görür et al. 1998) were formed by the convergence of the northern branch of Neo-Tethys between two continental units: the Sakarya Continent and the Kırşehir Block (Şengör and Yılmaz 1981). Sivas Basin is a typical foreland basin related to the collision (Görür et al. 1998). ...
This study is based around Karayün which is in the Sivas Tertiary Basin, one of the important sedimentary basins in Turkey. The units observed in the study area and nearby are Oligocene Hafik, Lower Miocene Karayün and Lower-Middle Miocene Karacaören Formations and Quaternary alluvium. This study focused on samples from the Karayün Formation due to the presence of alternations of bituminous shale levels in the formation. The studied bituminous shales are characterized by relatively high total organic carbon values up to 10.44 % and S2 values ranging from 0.01 to 89.02 HC/g rock, indicating fair to excellent source rock. Most of the bituminous shales are at the immature to early mature stage for hydrocarbon generation. Generally, genetic potential values are over 2 mg HC/g rock. The hydrogen index value of samples are between 9 and 887 mg HC/g total organic carbon (TOC) (on average 333.62 mg HC/g TOC). Oxygen index values vary between 17 and 557 mg CO2/g TOC (on average 135.35 mg CO2/g TOC). On the basis of Rock-Eval pyrolysis analysis, kerogens are type I/II and type II/III mixed. Dominant organic matter observed in this formation is algal amorphous organic matter. Thermal alteration index (TAI), Spore colour index (SCI), vitrinite reflectance values (R
o) and T
max evaluations indicate that maturity of the unit is between diagenesis and the early mature zone, and at the beginning of the hydrocarbon-producing stage. As a result of a series of analyses, it was found that the Karayün Formation has organic facies of B, BC and C and limited hydrocarbon generation potential in the basin.
... The research area is defined as 38°N to 42°N and 30°E to 35°E with the effect of the NAF to the north, the İnönü-Eskişehir and Akşehir Fault Zones to the west, Tuzgölü Fault to the south-east, and Ezinepazarı Fault to the east ( Figure 3). The active faults in this area were studied by Şaroğlu et al. (1987, 1992), Pampal and Kozlu (2000), Seyitoğlu (2007), Koçyiğit (1991Koçyiğit ( , 2000Koçyiğit ( , 2008aKoçyiğit ( , 2008bKoçyiğit ( , 2009), Koçyiğit and Deveci (2008), Dirik and Göncüoğlu (1996), Dirik et al. (1998), Çemen et al. (1999), Eren (2000), Dirik (2001), Bozkurt (2001), Koçyiğit et al. (2001), Özsayın and Dirik (2007), and Gökten and Varol (2010). A new active fault map of Ankara is prepared by using existing research results and by combining available information to close any gaps in previous studies (see Figure 3). ...
The capital and the second largest city of Turkey, Ankara, is generally considered to be safe in terms of seismic activities and earthquake hazard. However, recent studies and earthquakes experienced in the region showed that Ankara is not indeed seismically safe. As the number of studies on Ankara's seismic hazard increases, the number of scientists who claim that the earthquake hazard in Ankara is higher than expected also increases. However, to date no detailed analysis has been undertaken as to the earthquake hazard facing Ankara. This study has compiled data from the earthquake catalogues available in Turkey and employed the latest knowledge available to produce an Ankara-specific earthquake catalogue. Probabilistic seismic hazard analysis of the unified data was then used to produced peak ground acceleration (PGA) values for 5%, 10%, 20%, and 40% probability of exceedance over a 50-year return period. The PGA values at main rock sites were determined using the most appropriate attenuation relationship. These show an exceedance probability of 10% over a 50-year return period to range from 0.20 g to 0.25 g for the Ankara provincial districts of Ayas, Cankaya, Etimesgut, Sincan, and Yenimahalle; from 0.25 g to 0.30 g for Altindag, Golbasi, Kecioren, and Mamak; and from 0.30 g to 0.35 g for Akyurt, Cubuk, Elmadag, and Kazan.
... On a small scale, based on the type and nature of the active tectonic regimes and related structures such as faults and basins, an intracontinental tensional neotectonic regime and oblique slip normal faulting characterize the Çubuk district (Koçyiğit, 2003). In the area (Fig. 2), the tectonic unit is the Çubuk Fault Zone (ÇuFZ) which is a normal fault with an approximate trend of NE20°-30° (Kupan, 1977;Koçyiğit, 1991). It defines the margins of the NE-SW trending Çubuk basin. ...
This study mainly concentrates on the determination of site effects for the Plio-Quaternary and especially alluvial soils of the Çubuk district and its close vicinity in Ankara, Turkey. In the study area, particularly in the vicinity of the asymmetric graben that has formed due to the tectonic activities along the NE-SW trending normal faults, a microtremor survey was implemented to identify the local site response under a possible seismic event. The results were compared and correlated by using passive and active surface wave measurements, engineering geological and geotechnical deep borehole logs along with local geology and geological tectonic setting. Regarding the microtremor results, larger fundamental periods were acquired than expected over the area and the effect of the tectonic deformation on the stiffness of the soils was also observed at either the H/V curves or the shear wave velocity profiles. The results have demonstrated that geotechnical information down to a depth of 30 m may not be compared with the H/V parameters. The H/V amplitudes were not always accompanied with the higher periods in the Quaternary sediments. This could be due to the basin and basin edge effects observed particularly at the center and boundary of the basin, respectively. Additionally, the microtremor survey showed that the spectral ratio amplitudes derived by the H/V ratio is debatable and it is not a direct indicator of local soil behavior under a seismic excitation.
... Ankara'nın KKB'sında bulunan Yuvaköy çevresi, İç Anadolu'da bölgesel tektonik modellerde önemli rol oynayan anahtar yerlerden biri olarak Gökten vd. (1988) ve Koçyiğit (1991Koçyiğit ( ve 1992 tarafından incelenmiştir (Şekil 1). Koçyiğit (1992), Yuvaköy çevresinde Üst Kretase ofiyolitik melanjı ile Neojen sedimanter birimler arasındaki dokanağı yaklaşık D-B doğrultulu ve kuzeye eğimli bindirme fayı olarak haritalamıştır. ...
In the NNW of Ankara around Yuvaköy, the north dipping thrust faults between ophiolitic mélange and Neogene sedimentary rocks have been shown as field evidence of the “Ankara Orogenic Phase”, suggesting the continuation of intracontinental convergence until the Pliocene, as recently re-reported by scientists. To test this recent report, the tectonic contact between ophiolitic mélange and Neogene sedimentary rocks was re-mapped and geophysical methods were used to determine the dip direction of the tectonic contact. This study shows that the tectonic contact is a south dipping normal fault and there is no field evidence of post-Miocene N-S contraction in the region.
... The faults in the Ankara Basin are seismically active but are only capable of producing smaller earthquakes (Mo5). Recent seismic activity (Fig. 2) within about 50 to 75 km of Ankara includes the June 6, 2000 Orta earthquake and its aftershocks (M D ¼ 5.9, 5.2 and 5.0; [14]; and M W ¼ 6.1, 4.8 and 4.6; [15]), the July 31–August 9, 2005 Bala earthquake series (M L ¼ 5.3, 4.8 and 4.6; [14]) and the December 12–27, 2007 Bala earthquake series (M L ¼ 5.7 and 5.5; [14]). These local earthquakes are relatively moderate seismic events that can affect Ankara. ...
Regional site conditions relevant for seismic hazard studies can be derived from various geologic, seismologic, and geotechnical sources. In this study, site conditions are derived for the Ankara Basin in
Turkey by merging in situ seismic measurements of dynamic properties, geologic information, and some geotechnical boring information. Field seismic refraction surveys were performed at 259 sites in the project area to classify and characterize Plio-Pleistocene fluvial deposits and Quaternary alluvial and terrace deposits.The shear-wave velocity profiles of the near-surface geologic units are used to characterize site classes according to the International Building Code [International Code Council, ICC. International Building Code. Structural and fire-and life safety provisions (seismic, wind, accessibility, egress, occupancy and roof codes), 2006. Whittier, CA.] and theTurkish Seismic Code [Ministry of Public
Works and Settlement, 1998. Turkish Seismic Code, Specification for Structures to be Built in Disaster Areas, Ankara, Turkey], and to develop a regional model for the average shear-wave velocity in the top 30m. The resulting maps of site class indicate that the classification system for the Turkish Seismic Code results in a significant portion of the Ankara Basin being classified as Z4, the softest site class.The International Building Code site classification system results in most of the Ankara Basin being classified
as D, stiff soil. These differences are caused by the Turkish Seismic Code incorporating information from only the surface layer, while the International Building Code incorporates information from the top
30m.
... Based on the type and nature of the active tectonic regimes and related structures such as faults and basins as given in Fig. 3.2, an intracontinental tensional neotectonic regime and oblique slip normal faulting characterize the Çubuk district (Koçyiğit, 2003). In the area, the tectonic unit is the Çubuk Fault Zone which is a normal fault with an approximate trend of NE20º-30º (Kupan, 1977 andKoçyiğit, 1991). It defines the margins of the NE-SW trending Çubuk basin (Fig. 3.2). ...
... There are many faults having a capability to produce frequently small to moderate seismic events present in the Çubuk Region and the surrounding area. In the area, the main tectonic unit is the Çubuk Fault Zone which is a normal fault with an approximate trend of N20º-30º (Kupan, 1977, Koçyiğit, 1991. It defines the margins of the NE-SW trending Çubuk basin. ...
... These earthquakes are relatively moderate seismic events that might affect Ankara. On a regional scale, the Ankara region can be affected by the surrounding large-scale fault systems, particularly the North Anatolian Fault System (NAFS), Salt Lake Fault Zone (SLFZ) and Seyfe Fault Zone (SFZ), which are capable of producing large destructive earthquakes (M > 7.0; Koçyiğit, 1991;Koçkar, 2006). Some of the prominent examples of major events that have occurred along these systems around the Ankara region are the November 26, 1943 Kastamonu earthquake (M L =7.3), the February 1, 1944 Gerede earthquake (M L =7.3), and the August 13, 1951 Çankırı earthquake (M L =6.9) along the NAFS, and the March 19, 1938 Taşkovan-Akpınar earthquake along the SFZ (M L =6.6). ...
... These local earthquakes are relatively moderate seismic events that may affect Ankara. On a regional scale, the Ankara region may be affected by the surrounding large-scale fault systems, particularly the North Anatolian Fault System (NAFS), the Salt Lake Fault Zone (SLFZ) and the Seyfe Fault Zone (SFZ), which are capable of producing large destructive earthquakes (M > 7.0; Koçyiğit, 1991;Koçkar, 2006 place along these large-scale Fault Systems and Fault Zones might affect Ankara and its surroundings and thus have to be considered seriously in regards to seismic hazard assessment. ...
... The Triassic basement is composed of dark brown greywacke, black shale and diverse sized carbonate blocks (Kocyigit and Turkmenoglu, 1991). Yalincak formation, consisting of three main lithofacies from bottom to top, namely, debris flow conglomerate, braid plain conglomerate and sandstone and clay bearing finer clastics of floodplain origins, basin fill of Ankara city (Kocyigit, 1991). Detailed and recent information about Ankara city can be found in Yal and Akgun (2013) and Kockar and Akgun (2012). ...
... The research area has been studied by Şaroğlu et al. (1987, 1992), Pampal and Kozlu (2000), Seyitoğlu (2007), Koçyiğit (1991Koçyiğit ( , 2000Koçyiğit ( , 2008aKoçyiğit ( , b, c, d, 2009), Dirik and Göncüoğlu (1996), Dirik et al. (1998), Dirik (2001, Çemen et al. (1999), Eren (2000), Bozkurt (2001), Özsayın and Dirik (2007), and Gökten and Varol (2010) in order to specify active faults. The new active fault map of Central Anatolia was prepared by using all available research results and combining the available information to close any gaps from previous studies (Fig. 2). ...
The aim of this study is to investigate the seismicity of Central Anatolia, within the area restricted to coordinates 30–35° longitude and 38–41° latitude, by determining the “a” and “b” parameters in a Gutenberg–Richter magnitude–frequency relationship using data from earthquakes of moment magnitude (Mw) ≥ 4.0 that occurred between 1900 and 2010. Based on these parameters and a Poisson model, we aim to predict the probability of other earthquakes of different magnitudes and return periods (recurrence intervals). To achieve this, the study area is divided into six seismogenic zones, using spatial distributions of earthquakes greater than Mw ≥ 4.0 with active faults. For each seismogenic zone, the a and b parameters in the Gutenberg–Richter magnitude–frequency relationship were calculated by the least squares method. The probability of occurrence and return periods of various magnitude earthquakes were calculated from these statistics using the Poisson method.
Çalışmanın amacı, 1900 – 2020 yılları arasında meydana gelmiş Mw ≥ 4.0 olan deprem verilerinden yararlanarak ve Gumbel Uç Değerler Yöntemi’ni kullanarak Türkiye’nin başkenti olan Ankara ilini depremsellik ve deprem tehlikesi açısından incelemek ve deprem tehlike parametrelerini belirlemektir. Ankara ilinin deprem tehlike analizi 380 – 420 K enlem ve 300 – 350 D boylam koordinatları ile sınırlandırılmış alan içinde yer alan sekiz kaynak bölge içine düşen depremlerden yararlanarak yapılmıştır. Her kaynak bölgede hasara neden olabilecek büyüklükteki depremlerin yinelenme aralıkları, olası maksimum deprem büyüklükleri ve farklı büyüklükteki depremlerin oluşma olasılıkları saptanmıştır. Ankara ili ve yakın civarı içinde gelecek 100 yıl içinde Mw ≥ 7.0 büyüklüğündeki bir depremin meydana gelme ihtimalinin Kuzey Anadolu Fay Zonu kaynak bölgesinde (Bölge 1) en yüksek olduğu (%90) ve bunun dönüş periyodunun 43 yıl olduğu bulunmuştur.
The Ereğli‐Ulukışla Basin which is the focus of this study is situated at the south‐eastern edge of the Central Anatolian Cenozoic basins (Tuzgölü, Haymana, Çankırı‐Çorum, and Sivas), and is divided into two sub‐basins, the Aktoprak (AT) and Hacıbekirli‐Tepeköy (HT). These sub‐basins mainly comprise a stratigraphically discontinuous and laterally variable series, represented by ‘fluvio‐lacustrine’ siliciclastic and carbonate sediments deposited over a wide range of environments, including meandering and braided rivers, coastal fluvial and fan deltas, mixed carbonate‐siliciclastic shores, dry lake flats, and coal‐bearing swamps. In the Ereğli‐Ulukışla Basin, higher palaeotopographic conditions existed in the AT because of the uplift of the Central Anatolian Plateau during late Middle Miocene (Serravallian)‐early Late Miocene (Tortonian) and the subsequent uplift of the Taurus Mountains in the latest Miocene (Messinian) as deduced in the Tepeköy region (northeast) of the HT sub‐basin. Diversity and abundance of archaic pollen (Normapolles) in the pollen biostratigraphy decreased from the Eocene to Oligocene, while forms with advanced angiosperm morphology (post‐Normapolles), were observed with the increase in post‐Normapolles during the Miocene. The dominance of woody angiosperms in the pollen assemblages, and increasing variety and abundance of ‘open herbs’ and shrub pollen from the Early Miocene to Late Miocene defines an important change in flora. Furthermore, the palaeoclimatic conditions changed from humid‐subtropical to warm‐temperate during the sediment deposition in the Ereğli‐Ulukışla Basin. Recurrent arid phases during the Late Miocene are indicated by the deposition of reddish caliche conglomerates in broad dry lake flats (HT), and evaporites in local playa lakes (AT), respectively.
Mostly, The province of Ankara is known as a safe place in terms of seismicity and earthquake hazard. However, the earthquakes that have occurred in the recent years, and the studies have begun to show that it may not be such. Therefore, the seismicity and the seismic hazard of the region should be revised on the basis of current data and studies. The aim of this study is to determine the seismic hazard and to prepare an earthquake hazard map of Ankara by using the deterministic method. Deterministic seismic hazard analysis is applied for the province of Ankara and peak ground acceleration values at rock sites are determined by using two different the attenuation relationships and fourteen seismic source areas. In this study, peak ground acceleration values at rock sites is estimated to range from 0.1 to 0.6 g for Ankara province.
ZET Ankara ili genel olarak depremsellik ve deprem tehlikesi açısından güvenli bir yer olarak bilinir. Fakat son yıllarda meydana gelmiş olan depremler ve yapılan çalışmalar bunun böyle olmayabileceğini göstermeye başlamıştır. Bu nedenle güncel verilerin ve çalışmaların ışığı altında bölgenin depremselliğinin ve deprem tehlikesinin yeniden gözden geçirilmesi gerekmektedir. Çalışmanın amacı, deterministik (tanımsal) yöntemle Ankara ilinin deprem tehlikesini belirlemek ve deprem tehlike haritasını hazırlamaktır. Bu çalışma ile deterministik yöntem kullanarak, on dört kaynak bölge ve iki farklı azalım ilişkisinden yararlanarak ana kayada oluşabilecek maksimum yer ivmeleri hesaplanmış ve Ankara il sınırları içinde oluşabilecek maksimum yer ivme değerlerinin 0,1 g ile 0,6 g arasında değişebileceği bulunmuştur. ABSTRACT Mostly, The province of Ankara is known as a safe place in terms of seismicity and earthquake hazard. However, the earthquakes that have occurred in the recent years, and the studies have begun to show that it may not be such. Therefore, the seismicity and the seismic hazard of the region should be revised on the basis of current data and studies. The aim of this study is to determine the seismic hazard and to prepare an earthquake hazard map of Ankara by using the deterministic method. Deterministic seismic hazard analysis is applied for the province of Ankara and peak ground acceleration values at rock sites are determined by using two different the attenuation relationships and fourteen seismic source areas. In this study, peak ground acceleration values at rock sites is estimated to range from 0.1 to 0.6 g for Ankara province.
Tertiary Çankiri - Çorum Basin is one of the biggest basin covering evaporitic formations in the Central Anatolia. During borehole drills carried out in Bozkir Formation which contain Pliocene aged evaporites in the basin, a thick rocksalt (halite, NaCl) deposit was detected that consisting of glauberite (Na2Ca(SO4)2) interlayers (sabhka) synchronous with sedimentation. Rocksalt bearing layers in Bozkir formation which was deposited in playalake - sabhka environment, where seasonal changes are effective, were first defined as Tuz member in this study. Bozkir formation was divided into three zones in drillings carried out in sabhka - playa - lake transitional environment. From bottom to top, these are ordered as claystone-less anhydrite zone, rock salt-claystone-anhydrite-glauberite zone (Tuz member) and claystone-gypsum-less anhydrite zone. Rocksalt was cut in thicknesses reaching 115 meters within Tuz member. Rocksalt (playa-lake) which is mostly bedded and white, pale/dark gray colored is conformable with sedimentation and is low dipping. The level at which glauberite deposition within Tuz member is observed the thickest was defined as glauberite-mudstone zone. Glauberite mineral which is observed as disc and rosette shaped individual forms within mudstone dominant matrix was formed as a diagenetic mineral in saline mudşat environment (sabhka). In geochemical analyses carried out (XRD, XRF, SEM) it was detected that glauberite mineral had been crystallized following anhydrite mineral within matrix that includes complex crystal forms in sabhka environment, halite mineral had grown on glauberite mineral and it was sometimes observed in the form of fracture and crack infill. The glauberite mineral deposition which does not have an economical thickness is of great importance in terms of the existence of fossil Na-sulfate deposition scientifically in Çankiri-Çorum Basin.
Tectonic escape is frequently considered to result from compression in a collisional belt, a free boundary opening the way to lateral extrusion of rigid blocks. However, in Anatolia the complex tectonic history provides an opportunity to better understand why a widespread late Cenozoic extension occurs instead of generalized compression. In contrast to common opinion, we argue in this article that the major thickening of the Anatolian plateau did not occur during late Cenozoic times as a consequence of the Africa-Arabia collision with Eurasia and related compression. When examining the distribution of the late Cenozoic deformation in eastern Anatolia, the main argument is that the region was subjected largely to extension and strike-slip tectonics. Compression was limited to the narrow eastern Taurus belt and to a north-south strip comprising the Afsin and Gurun arcs and the Sivas basin. This is shown by a review of the literature and by complementary examination of radar and regional-scale Digital Elevation Model imagery. A second argument is that a major crustal thickening occurred prior to the late Cenozoic during a major collisional event that took place in the Eocene. Crustal thickening was followed by extensional collapse of Anatolia during the Neogene-Quaternary after the opening of the Aegean basin free border during the Oligocene. Consequently, the escape of Anatolia largely implies body forces previously stored in the lithosphere, inducing extensional collapse over crustal-scale detachments, triggered by the onset of a free boundary in the west. This tectonic evolution is related to the progressive propagation of the extension from west to east, which induced eastward propagation of the North Anatolian fault forming the northern boundary of the area submitted to tension.
The main goal of this study is to assess the organic geochemical properties and hydrocarbon generation potential of the Tertiary units in the Sivas Basin which is one of the largest sedimantery basins in the Central Anatolia, Turkey. In this investigation, 200 representative samples were collected from the Tertiary sedimentary rock outcrops. In addition, 15 scaled columnar sections were measured and 187 samples were also collected from these sections. Hydrocarbon generating potential and the maturity levels of the Tertiary units along with the geological history in this basin were determined by means of the total organic carbon (TOC) analysis, Rock-Eval pyrolysis, vitrinite reflectance (Ro) and the organic petrographical observations. Kerogen slides of 96 samples containing high TOCs were prepared to determine the organic matter types. Information about maturity degrees were also obtained using the spore fluorescence colours and the vitrinite reflection (Ro).
The aim of this study is to evaluate the Central Anatolia region of Turkey with regard to seismicity and earthquake hazard using available data on Mw ≥ 4.0 earthquakes that occurred between 1900 and 2011 and the Gumbel Extreme Values method. Additionally, the study also aimed to determine the parameters associated with earthquake hazards. The seismicity analysis for the Central Anatolia region was performed by evaluating past earthquakes in six source regions located within the area falling within 38–41° N latitude and 30–35° E longitude. For each region, the researcher determined the occurrence probability and the return period for earthquakes strong enough to cause material damage and the possible maximum magnitudes for earthquakes that might occur in the future within a certain time period. Based on the study results, the researcher determined that the North Anatolian fault zone (zone 1) in Central Anatolia is the region characterized by the highest probability (89 %) than an Mw ≥ 7.0 magnitude earthquake will occur within the next 100 years and that the return period in this zone for such an earthquake is 50 years.
: Early Miocene (ca. 21–18 Ma) volcanism in the Karacadaǧ area comprises three groups of volcanic rocks: (1) calcalkaline suite (andesitic to rhyolitic lavas and their pyroclastics), (2) mildly-alkaline suite (alkali basalt, hawaiite, mugearite, benmoreite and trachydacite), and (3) a single trachyandesitic flow unit. Field observations, 40Ar/39Ar ages and geochemical data show that there was a progressive temporal transition from group 1 to 3 in a post-collisional tectonic setting. The calcalkaline suite rocks with medium-K in composition resemble those of subduction-related lavas, whereas the mildly-alkaline suite rocks having a sodic tendency (Na2O/K2O=1.5–3.2) resemble those of within-plate lavas. Incompatible element and Sr-Nd isotopic characteristics of the suites suggest that the lithospheric mantle beneath the Karacadaǧ area was heterogeneously enriched by two processes before collision: (1) enrichment by subduction-related processes, which is important in the genesis of the calcalkaline volcanism, (2) enrichment by small degree melts from the astenosphere, which dominates the mildly alkaline volcanism. Perturbation of the enriched lithosphere by either delamination following collision and uplift or removal of the subducted slab following subduction and collision (i.e., slab breakoff) is the likely mechanism for the initiation of the post-collision volcanism.
Considering the high population growth rate of Ankara, it is inevitable that landfill(s) will be required in the area in the near future to sustain the sanitary waste disposal needs of the city. The main scope of this study is to select alternative landfill sites for Ankara based on the growing trends of Ankara toward the northwest, particularly toward the Sincan municipality, and to eventually select the best alternative through utilizing multi-criteria decision making. Landfill site selection was carried out utilizing Geographic Information System (GIS) and Multi-Criteria Decision Analysis. A number of criteria, namely, settlement, slope, proximity to roads, geology, availability and proximity of landfill containment material (i.e., clay for composite lining system), suitability for agriculture, erosion, vegetation cover and lineament system were gathered in a GIS environment. Each criterion was assigned a weight value by applying the Pairwise Comparison Method and the Analytical Hierarchy Method. In order to choose the best alternative, the Technique for Order Preference by Similarity to the Ideal Solution, which is regarded as an ideal point method, was applied and a landfill site was selected. The geotechnical properties of the so-called "Ankara clay" that shows widespread distribution in Ankara were reviewed and assessed for its suitability as a compacted clay liner.
The purpose of this study was to select alternative landfill sites for Ankara based on the growing trends of Ankara toward the GolbaAYA +/- municipality, and to eventually select the best alternative through the use of decision-making tools. Geographic information systems (GIS) and multi-criteria decision analyses were employed to perform landfill site selection. Several criteria, including geology, slope, proximity to roads, availability and proximity of landfill containment material, settlement, suitability for agriculture, vegetation cover, erosion, and lineament system were gathered in a GIS environment. A weight value was assigned to each criterion by applying the pairwise comparison method and the analytical hierarchy method. An ideal point method, namely, the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) was applied to choose the best alternative landfill site. The geotechnical properties of "Ankara clay", which shows widespread distribution in Ankara, were reviewed and assessed for the clay's suitability as a single, compacted clay liner and as a component of a geomembrane-compacted clay composite liner for the alternative landfill site selected. The HELP model was employed in order to determine the cumulative, mean leachate head and cumulative, unitized expected leakage rate amounts through the landfill. Four different profiles, from the least conservative to the most conservative, were created and analyzed.
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