Sarıyer-Şile bindirmesi
Sariyer-Şile thrust
Yazar: HALİL CAN AYDIN
Danışman: PROF. DR. ARAL OKAY
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Jeoloji Mühendisliği Ana Bilim Dalı / Jeoloji Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2020
Konu: Jeoloji Mühendisliği = Geological Engineering

Özet:
Bu çalışma, İstanbul ilinin Sarıyer ve Beykoz ilçelerinde gözlemlenen Sarıyer-Şile Bindirmesi'nin yapısal özelliklerini anlamak için yapılmıştır. 2018 yılının Kasım ve 2019 yılının Eylül ayları arasında saha gözlemleri yapılmıştır. Sarıyer-Şile Bindirmesi İstanbul ilinin kuzey yarısında bulunan bindirme fayıdır. Fay, İstanbul ilinin iki yakasında da gözlemlenebilmektedir. Sarıyer-Şile Bindirmesi, İstanbul Paleozoyiği ve Triyas yaşlı birimleri temsil eden Gebze Grubu olarak tanımlanan birimler ile İstanbul ilinin kuzeyinde bulunan Kretase yaşlı volkanik birimlerin sınırını temsil etmektedir. Sarıyer-Şile Bindirmesi, bahsi geçen birimlerin dokanağını oluşturmaktadır ve bu özelliğinden dolayı birçok araştırmaya konu olmuştur.
Çalışma boyunca temel olarak saha gözlemlerine odaklanılmıştır. Arazi çalışmasında jeolojik birimler ve yapısal unsurlar, İstanbul iline ait topografik haritalara işlenmiştir. Necdet Özgül tarafından hazırlanan İstanbul ilinin jeolojik haritasından yararlanılmıştır. Bahsi geçen çalışma İstanbul ilinin jeolojik birimlerini, genel özellikleriyle sınıflandıran güncel bir örnek olduğu için formasyon isimlendirmelerinde bu çalışmadan yararlanılmıştır.
İstanbul ilinin kuzey bölgelerinde bulunan çalışma alanında, stratigrafik olarak temel birimleri temsil eden Paleozoyik yaşlı formasyonlar bulunmaktadır. Çalışma alanı boyunca gözlemlenen İstanbul Paleozoyiği'ne dahil olan birimler, yaşlıdan gence doğru Alt Ordovisiyen yaşlı Kurtköy Formasyonu, Üst Ordovisiyen-Alt Silüriyen yaşlı Aydos Formasyonu ve Yayalar Formasyonu, Üst Silüriyen-Alt Devoniyen yaşlı Pelitli Formasyonu, Alt-Orta Devoniyen yaşlı Pendik Formasyonu, Orta ve Üst Devoniyen-Alt Karbonifer yaşlı Denizli Köyü Formasyonu, Alt Karbonifer yaşlı Baltalimanı Formasyonu ve Alt Karbonifer yaşlı Trakya Formasyonu'nu içermektedir. İstanbul Paleozoyik istifinin üzerinde Gebze Grubu'na dahil Alt Triyas yaşlı Erikli Formasyonu, Alt-Orta Triyas yaşlı Demirciler Formasyonu, Alt-Orta Triyas yaşlı Ballıkaya Formasyonu, Üst Triyas yaşlı Tepecik Formasyonu bulunmaktadır. Sarıyer-Şile Bidirmesi boyunca, İstanbul Paleozoyiği'nin ve Gebze Grubu'nun üzerinde farklı özelliklere sahip olan Kretase yaşlı Garipçe Formasyonu bulunmaktadır. Üst Oligosen-Alt Miyosen yaşlı İstanbul Formasyonu, genellikle Garipçe Formasyonu'nun, yer yer İstanbul Paleozoyiği'nin üzerini örtmektedir. Son olarak güncel alüvyon birimi, bahsi geçen tüm formasyonların üzerinde bulunmaktadır.
8 farklı bölgede incelenen Sarıyer-Şile Bindirmesi yapılaşma ve sık bitki örtüsünden dolayı sürekli olarak takip edilememiştir. 5 noktada yüzlekler incelenmiş ve 19 noktada daha önce yapılmış olan 31 sondajın verisi sunulmuştur. Fay düzleminin üzerinde ve altında bulunan birimlerin deformasyona uğrayıp birbiri içerisinde yer alması ve birçoğunun fazlasıyla ayrışmış olması çalışmayı etkileyen bir başka faktördür. Deformasyona bağlı ayrışmanın ve arenalaşmanın fazlasıyla gözlemlendiği Kretase yaşlı volkanikler İstanbul Paleozoyiği'ne göre daha dirençsiz kalmıştır. İstanbul ilinin Anadolu Yakası'nda Anadolu Kavağı, Kaynarca Köyü ve Mahmut Şevket Paşa civarında inceleme yapılırken Avrupa Yakası'nda Sarıyer, Zekeriyaköy, Uskumruköy ve Gümüşdere Köyü civarında inceleme yapılmıştır. 
Çalışma sonucunda Sarıyer-Şile Bindirmesi'nin çalışma alanında kabaca KB-GD uzanımda olduğu ve Sarıyer-Şile Bindirmesi'nin, incelenen lokasyonlara göre bindirme özelliği taşıdığı anlaşılmıştır. Sarıyer-Şile Bindirmesi'nin, incelenen lokasyonlarda bindirme özelliği taşıdığı ancak genel olarak deformasyona uğramış birimlerden dolayı 3 inceleme noktası haricinde eğiminin net olarak gözlenemediği ortaya konmuştur. Yüzleklerde yapılan araştırmaya göre bindirmenin eğiminin Gümüşdere Köyü'nün güneyinde bulunan 3 lokasyonda 45 derece civarı olduğu saptanırken, Maden Mahallesi kuzeyinde bulunan lokasyonda 10-15 civarında olduğu gözlemlenmiştir. Bahsi geçen lokasyonlarda 50 cm ile 1 metre arasında değişen kalınlığa sahip fay kili gözlemlenmiştir. Sondaj verileri değerlendirilerek bindirme sınırının derinliği saptanmıştır. Sarıyer-Şile Bindirmesi'nin 100-200 metre aralığında bir deformasyon alanı oluşturduğu sonucuna ulaşılmıştır. İstanbul Paleozoyiği'nin, Triyas yaşlı Gebze Grubu ile Kretase yaşlı Garipçe Formasyonu'nun üzerine bindirdiği, sondaj çalışmaları ile desteklenmiştir.

Abstract:
This study was carried out to understand the structural features of Sarıyer-Şile Thrust observed in Sarıyer and Beykoz districts of İstanbul. Field observations were made between November 2018 and September 2019. Sarıyer-Şile Thrust is the thrust fault located in the northern half of İstanbul. The fault can be observed on both sides of İstanbul. The Sarıyer-Şile Thrust represents the boundary of units defined as the Triassic Gebze Group, Paleozoic units of İstanbul, and the Cretaceous volcanic units located in the north of İstanbul. Sarıyer-Şile Thrust is the contact of the mentioned units and has been the subject of many studies due to this feature.
Throughout the study, the main focus was on field observations. In the field study, geological units and structural elements are embedded in topographic maps of İstanbul. Geological map of İstanbul province prepared by Necdet Özgül was used. Since this study is an up-to-date example that classifies the geological units of İstanbul province with its general characteristics, this study was used in formation naming.
Paleozoic formations representing stratigraphically basic units are found in the study area located in the northern regions of İstanbul province. Units included in the İstanbul Paleozoic observed throughout the study area, from the old to young, Lower Ordovician Kurtköy Formation, Upper Ordovician-Lower Silurian Pelitli Formation, Lower-Middle Devonian Pendik Formation, Middle and Upper Devonian-Lower Carboniferous Denizli Köyü Formation include Lower Carboniferous Baltalimanı Formation and Lower Carboniferous Trakya Formation. On the Paleozoic sequence of İstanbul, there are Lower Triassic Erikli Formation, Lower-Middle Triassic Demirciler Formation, Lower-Middle Triassic Ballıkaya Formation, Upper Triassic Tepecik Formation. Throughout Sarıyer-Şile Thrust, there is a Cretaceous Garipçe Formation which has different features on İstanbul Paleozoic and Gebze Group. The Upper Oligocene-Lower Miocene aged İstanbul Formation generally overlies the Garipçe Formation, and the Paleozoic of İstanbul in places. Finally, the current alluvium unit is above all the formations mentioned.
The Sarıyer-Şile Thrust, which is examined in 8 different location, could not be followed continuously due to the construction and frequent vegetation. Outcrops were examined at 5 points and data from 31 drillings previously made at 19 points were presented. Another factor affecting the study is that the units located above and below the fault plane undergo deformation and are located within one another, and many of them are highly decomposed. The Cretaceous volcanics, where deformation is highly observed, remained less resistant than the Paleozoic of İstanbul. In the Anatolian Side of the province of İstanbul, Anadolu Kavağı, Kaynarca Village and Mahmut Şevket Paşa were investigated, while in the European side, Sarıyer, Zekeriyaköy, Uskumruköy and Gümüşdere Village were examined.
The first location is located in Sarıyer's Gümüşdere Village. In this study area, the points 31, 33 and 34 are the closest observation sites to the fault boundary. Location 1 is located approximately 1 km southwest of the Gümüşdere District of Sarıyer. This location is located at the intersection of Bahçeköy-Gümüşdere Road and North Marmara Motorway. The slope angle of the southwest slope fault is 45-50 degrees and contains a light brown-colored fault clay with varying thickness in the range of 10-50 cm. In addition to the deformation zones, which are the most important factor in distinguishing the fault at the mentioned location, the fault includes the gray and light gray sandstone units of the Erikli Formation in the north, while the Trakya Formation in the south contains brown sandstone units.
The second location is located at Özsoylar Quarry, 1,5 km southwest of Arıköy Site in Uskumruköy. An investigation was carried out in the west and south of the quarry. Examination points 28, 29 and 32 are located in this region. Location 2 is one of the points where Sarıyer-Şile Thrust can be observed most clearly due to the cuts in the quarry. Points 28, 29 and 32 are the closest points to the fault boundary to be examined. The boundary between the Trakya Formation and the Triassic Erikli Formation is clearly visible in the observation area around the pond of the Sarıyer-Şile Thrust. The fault with a slope direction of SW has a slope of approximately 45 degrees. In addition, in the fault zone, there is a dark gray and partly black fault clay with a thickness of approximately 1 meter. As we go north, units belonging to Cretaceous Garipçe Formation are observed. The units belonging to the Trakya Formation are located on the andesites of the Garipçe Formation at the examination point 32, located approximately 350 m northeast of the pond. There are approximately 40-50 cm thick black and dark gray colored fault clays between the two formations. The slope of the fault with SW slope direction is 45 degrees.
The third location is located about 1 km south of Zekeriyaköy District. The study area is located on the south of Cansit Villas on the 2nd Street. Drills numbered S17, S18, S19, S20 and S21 were made at location 3 and fault was observed at examination point 24. At point 24, the mudstone units of the Trakya Formation are located above the tuff units of the Cretaceous Aged Garipçe Formation. Location 3 is one of the points where Sarıyer-Şile Thrust fault can not be observed clearly due to the residences. For this reason, the drillings studied in the region have been researched and drilling logs and core photographs have been presented. The geological cross-section was formed by combining the fault boundaries obtained from the drillings at location 5. It is understood from the drills used in section A-A' that the fault passes 3-10 m deep from the surface.
The fourth location is located in the Kasapçayırı District of Sarıyer. There are S13, S14, S15 and S16 drillings in this study area. Location 4 is located within the North İstanbul site in Kasapçayırı District of Sarıyer. There are no outcrop due to the construction around the Location 4. Two different geological sections were created by combining the boundaries of the faults obtained from the drillings in Location 4. It is understood from the sections positioned to cross each other, the drills used in the A-A' section, while the fault passes 4-15 m deep from the surface, in the B-B' section, the fault is located 5-15 m deep.
Location 5 is on Kilyos Road, 300 m southwest of Acarlar Site in Zekeriyaköy. An investigation was carried out along a 400 m line on Kilyos Road. Examination points 10 to 20 and S12 are located in this region. Points 10-20 are for outcrop, point S12 is the drilling point. Location 5 is one of the points where Sarıyer-Şile Thrust is not clearly observed on Kilyos Avenue due to vegetation and construction. The existence of the sites made it difficult to investigate. Point 13 is the closest point to the fault boundary to be examined. The deformed levels of the Trakya Formation, which we will define as the thrusting unit, can be distinguished when advancing in the northeast direction along Kilyos Road, which is considered to be the place of the fault plane due to the increase in the magnitude of the deformation. The burgundy, white and yellow tuff units of the Garipçe Formation in the north are below the dark gray shale and micaceous sandstone levels of the Trakya Formation in the south.
The sixth location is located 750 m south of Maden District. Examination points 4, 7, 36, S3-S11 are located in this location. Points 4, 7 and 36 are road tracks, points S3, S4, S6, S7, S8, S9, S10 and S11 are drilling points. Location 6 is one of the points where Sarıyer-Şile Thrust can not be observed clearly due to the residences. For this reason, the drillings studied in the region have been researched and drilling logs and core photographs have been presented. The Sarıyer-Şile Thrust was cut in the selected drills. There are a total of 8 boreholes in the region named as Location 6. The unit mentioned in the boring logs with the name of Sarıyer Formation corresponds to Garipçe Formation. In all of the drillings presented, the units belonging to the Lower Carboniferous Trakya Formation are located on the units belonging to the Cretaceous Garipçe Formation. Due to the very low core efficiency, the fault limit can not be clearly observed. The core drilling efficiency is thought to be low due to the drilling on the fault zone. 2 different geological sections were created by combining the fault boundaries obtained from the drillings in Location 6. It is understood from the sections located parallel to each other, the drills used in the A-A' section, while the fault passes 3-10 m deep from the surface, in the B-B' section, the fault is located 3-7 m deep.
The seventh location is located in the Yenimahalle District of Sarıyer. There are examination points named 1, S1 and S2 in the region. Point number 1 is located on Eski Sular Road, south of Yusuf Ziya Öniş Stadium. The borehole named S1 was against the State Hospital, while positioned near Şh. Mithat Yılmaz Road, the borehole named S2 is opposite the Yusuf Ziya Öniş Stadium and on Nalbant Çeşme Street. Location 7 is one of the points that Sarıyer-Şile Thrust does not face due to residences. As it is understood from the examination point numbered 1 and drill named S1, the Denizli Köyü Formation, where the Upper Devonian-Lower Carboniferous aged limestone and clayey limestone units are observed, is located above the Cretaceous volcanics.
The eighth location is located about 2 km southeast of Kaynarca Village. The study area is on Yunus Street, which is connected to Dereboyu Street. An investigation was carried out along a line of approximately 350 m on Yunus Street. Examination points 62 and 63 are located in this region. Location 8 is one of the points where Sarıyer-Şile Thrust is not clearly observed due to frequent vegetation. Point 62 is the closest point to the fault boundary to be examined. The fault observed on Yunus Street, located in the location 8 observation zone of Sarıyer-Şile Thrust, is not very clear due to the units that are completely decomposed and pushed into each other.
It has been demonstrated that Sarıyer-Şile Thrust has a thrust feature in the studied locations, but its inclination can be clearly observed except for 2 outcrop due to the units deformed in general. According to the survey conducted in the outcrops, the slope of the thrust was found to be around 45 degrees in 3 locations south of Gümüşdere Village, while it was observed to be around 10-15 in the north of Maden District. Fault clay with a thickness varying between 50 cm and 1 meter was observed at the mentioned locations. The depth of the thrust limit was determined by evaluating the drilling data and it was concluded that the Sarıyer-Şile Thrust formed a deformation area in the range of 100-200 meters. It was understood that the Paleozoic of İstanbul overlaid the Triassic Gebze Group and the Cretaceous Garipçe Formation as well as drilling results.