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1 Introduction Contents 1.1 Scope 1.1.1 1.1.2 1.1.3 1.1.4 of the Thesis . . . . . . . . . . . . . . Models of orogenic plateaus . . . . . Generalities of orogenic plateaus . . Central Anatolian Orogenic Plateau Aims of the Thesis . . . . . . . . . . 1.2 Tectonic setting of Turkey . . . . . 1.2.1 Tectonic plates arrangement 1.2.2 Tectonic slabs . . . . . . . . 1.2.3 Temporal evolution . . . . . 1.3 . . . . . 3 3 4 5 8 . . . . 9 9 10 12 Structure of the Thesis . . . . . . . . . . . . . . . . . . . . . . 14 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . Geologic setup . . . . . . . . . . . . . . . . . and motions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “Doubt is not a pleasant condition, but certainty is absurd.” Voltaire 3 Introduction 1.1 Scope of the Thesis Research on the mechanics and time-span of the processes behind orogenic plateau growth currently foments an intense discussion between erodibility-climate and tectonic schools [e.g. Molnar and England, 1990; Sobel and Strecker, 2003; Sobolev and Babeyko, 2005; Cloetingh and Willett, 2013]. The accurate quantification of the competing tectonic and climatic processes is key to understanding the main governing forces and the nature of feedback shaping the Earth’s surface [e.g. Garcı́aCastellanos and Cloetingh, 2011]. Some open questions in this debate are: • Is the surface uplift, and thus the plateau topography, a consequence of primarily tectonic, geomorphic, or climatic processes? • What are the time scales of plateau topography development? • How does the surface morphology and the lithosphere of the plateau evolve in time and what feedback processes are involved? 1.1.1 Models of orogenic plateaus While the climatic-erodibility models relate the tectonic activity to climate, rock erodibility, and precipitation power during incipient relief development [e.g. Sobel, 2003; Garcı́a-Castellanos, 2007], the tectono-structural and thermo-mechanical models understand the plateau buildup in relation to accretion/removal of crustal or lithospheric material, magmatic/tectonic underplating or rheological changes [e.g. Molnar, 1984; Allmendinger et al., 1997; Clark, 2012] (Fig. 1.1). Tectono-structural and thermo-mechanical models are divided into crustal and/or lithospheric shortening, tectonic or magmatic underplating, lower crustal flow, mantle delamination or detachment, slab break-off, and lithospheric thinning by extrusion. However, these models are not always able to entirely explain certain features of orogenic plateau development. Erodibility models Tectonic models Orographic precipitation Effective orographic barrier Dry intramountain climate Lower crustal flow Intracontinental subduction Delamination / Detachment / Break-off Extrusion Shortening Tectonic uplift Endorheism Sediment trapping, high plateau Understrusting / Tectonic doubling Deformation propagates forelandwards Higher pressure under orogen axis Figure 1.1: Summary of mechanisms of plateau formation. Slightly modified after Garcı́aCastellanos [2007] and http://www.geo.arizona.edu/. 4 Chapter 1 The evolution of the plateau morphology over time may be due to: Tectonic uplift and outward orogenic propagation. Leading to the transferral of foreland terrains into intramountane regions and the transformation of former foreland basins into younger interior basins. This tectonic process modifies the sedimentary dynamics of these basins, now internally drained by river networks that are incapable of ejecting sediments out of the system. This decrease in erosional capacities, caused by margin growth, forces internal aridification, overfill, and amalgamation of the intramountane basins that eventually flatten the orogen interior. Climatic contrast caused by relief initiation. Leading to a protracted contrast in precipitation and run-off, and therefore, in erosional power. This climatic effect, caused by long-lasting wind and rain shadows, leads to progressive aridification, hydrologic isolation and sediment trapping in the leeward side of the orogen, and high-discharge river networks with strong erosional capacity in the windward areas. The sedimentary basins shift from exo- to endorheic and their sedimentary accumulations create loads in the interior of the plateau that eventually force the propagation of the deformation forelandwards, orogen outward growth, and consequently tectonic uplift [e.g. Strecker et al., 2009a]. The determination of the causation relationship between these obviously interconnected cycles remains elusive. Orogenic plateaus are great “natural laboratories” to unravel the feedbacks amongst surface and deep-seated processes, and the relative relevance of each individual factor. 1.1.2 Generalities of orogenic plateaus Orogenic plateaus are tectonomorphic features characterized by elevated yet subdued semi-arid interiors, flanked by steep humid margins up to several kilometers high. Despite the broad range of scales and possible forming mechanisms shown by orogenic plateaus around the globe, they share some unifying characteristics (Fig. 1.2); (i) they can be described morphologically as a broad, roughly-flat, high surface, bounded by elevated steep margins; (ii) they display a high climatic precipitationerosion contrast between the arid, mainly endorheic basins in the interior with limited sediment circulation, and the humid, rainy flanks with exorheic rivers of high discharge; (iii) they have a thick crust, in excess of 40 km, and often a thin mantle lithosphere of ∼40−50 km. Thus, they have an anomalously high heat flow. Orogenic plateaus develop in a variety of contractional settings as integral parts of the largest modern mountain ranges on Earth. Some outstanding examples are the Colorado Plateau in the North America Cordillera, the Tibetan Plateau in the Himalayas, the Puna-Altiplano Plateau in the Central Andes, and the Iranian Plateau [e.g. Bird, 1979; Nelson et al., 1996; Allmendinger et al., 1997; Şengör et al., 2003]. This Thesis’ case study, the Central Anatolian Plateau [Strecker et al., 2009b], is not an exception, and is developing in the complex convergence zone between the Eurasian, African, and Arabian plates. 5 Introduction 100’s Km Endorheism 2-8 Km 40-80 Km Km 10 Endorheism S.L. 40-50 Km 35-50 Km Crust Mantle Lithosphere 0 50 100 Asthenosphere 150 Figure 1.2: Conceptual sketch of orogenic plateaus seen in cross section (not to scale). 1.1.3 Central Anatolian Orogenic Plateau - Geologic setup The Vertical Anatolian Movements Project (VAMP), a multidisciplinary effort built within the TOPO-EUROPE large-scale collaborative research program (EUROCORES) of the European Science Foundation (ESF) [Cloetingh et al., 2009], first identified the Central Anatolian Orogenic Plateau (CAP) as a young, but fully representative, continental plateau [Strecker et al., 2009b]. The CAP, located in Central Turkey, is a more accessible (smaller size and lower relief) orogenic plateau when compared with other more notorious orogenic plateaus (such as the Tibetan Orogenic Plateau), which therefore makes it ideal to deepen our understanding of orogenic plateau formation. However, until recently, the CAP has been disregarded, while many studies have centered their attention around bigger orogenic plateau systems [e.g. Powell, 1986; Yin and Harrison, 2000; Clark et al., 2006; Rowley and Currie, 2006]. The CAP covers a ∼350 km wide area between the Aegean extensional province and the Bitlis-Zagros contractional domain. It extends, in the N−S direction, from the Black Sea to the Mediterranean (see Fig. 1.3). The Pontides and Taurus mountain ranges, in the north and south, represent the flanks of the plateau and reach elevations of more than 3000 m. The roughly flat CAP interior, represented by Central Anatolia, is located at elevations of 1000 − 1300 m. Two major rivers dissect the higher elevations of the flanking mountain ranges. In the north, the Pontide Mountains are incised by the Kızılırmak River, which discharges in its delta after a journey of ∼1350 km in the plateau interior. In the south, the Göksu River, which feeds the homonym delta, transects the Taurus Mountains and enters the Mediterranean at Silifke. Based on Pn tomography and receiver function analysis [Mutlu and Karabulut, 2011; Vanacore et al., 2013, respectively], the CAP crust in Central Anatolia is reported to be 35±2 km or thicker, up to ∼47 km. These thicknesses increase towards the east, reaching up to ∼55 km, and the south, ranging from 40 to 47 km on the south Turkish coast. Further south, normal thicknesses are observed, with Moho depths of ∼30 km in Cyprus. Decreasing thicknesses are also found for West Anatolia and the Aegean Sea, with values between 28±2 and 33±2 km. Central Anatolia presents a hot and thinned mantle lithosphere, as seen in high heat flow values, normally in excess of 50 mW/m2 [Ateş et al., 2005; Dolmaz et al., 2005]. 6 Chapter 1 In the CAP, widespread Mid-Cenozoic rocks cover the Mesozoic to Palæogene rocks, related to amalgamated microcontinents [e.g. Şengör and Yılmaz, 1981; Robertson, 1998b]. In this Thesis, these rocks are assigned as basin basement rocks, independently of their nature (metamorphic or otherwise). Overlying basement, the basin infill contains continental pre-Miocene rocks, named here pre-Miocene substratum (PMS), marine Miocene rocks, and Plio-Q rocks, again continental in character. The interior of the Central Anatolian Orogenic Plateau In the interior of the CAP, at elevations around 1 km, thick lake and fluvial deposits form a series of Miocene-Quaternary sedimentary basins. In many of these interior basins, Miocene and older rocks are covered by important sequences of Pliocene and Quaternary deposits, a result of the confinement caused by the north and south orogenic barriers. For most of Central Anatolia, Neogene deposits are continental and poorly dated, and outcrops are limited, with some notable exceptions, such as the Çankırı Basin [Kaymakci, 2000]. Miocene kinematic and structural data is relatively minor and the tectonic regime of the area is a matter of debate, with possibilities ranging from strike-slip [e.g. Şengör et al., 1985] or extension [e.g. Dhont et al., 1999] to coeval extension and compression [Genç and Yürür, 2010]. Moreover, no link has been established with the uplift events in the margins of the CAP-system. In a central position, the Tuz Gölü Basin is a major representative amongst the CAP interior basins [Dirik and Erol, 2000]. Understanding the Miocene structural evolution of the Tuz Gölü Basin in its regional picture will provide relevant information on the genetic nature of the CAP. The southern margin of the Central Anatolian Orogenic Plateau With elevations locally in excess of 3000 m, the arcuated Taurus Range forms the southern flank of the Central Anatolian Orogenic Plateau (SCAP). Basin basement rocks are in the Taurus Mountains unconformably overlay by PMS and Miocene rocks. As an outstanding example, the incision of the Göksu River in the modern Taurus exposes thicknesses of this Miocene sequence up to 1600 m (up to 2300 m, considering the PMS [Cosentino et al., 2012]). These Miocene marine sediments were deposited in a single basin and have been related to those found in the east (Adana Basin) and west (Antalya Basin) [Karabıyıkoğlu et al., 2000]. Towards the north, in the Karaman region, an erosional surface marks the transition of these marine rocks to the Anatolian basement. This erosive termination might correlate with similar erosive surfaces seen between the thick Miocene-Recent continental rocks and the aforementioned basement [Monod et al., 2006]. Towards the south, correlative sediments are found in the offshore Cilicia Basin [Aksu et al., 2005a], in the Kyrenia Range, and in the Messaoria Basin in north and central Cyprus [McCay, 2010] (See Fig. 1.5). It can therefore be assumed that these sediments initially belonged to one single subsiding area during Early to Middle Miocene times and that progressive formation of the SCAP caused the end of marine sedimentation of the northern areas, which is dated as Late Tortonian (∼8 My) by Cosentino et al. [2012]. This evolution is in agreement with the disruption of a palæoriver network and the reestablishment of a younger one, as observed by Monod et al. [2006] in SW Turkey. North of Manavgat, fossil river morphologies are seen at an elevated high surface only partially affected by the modern drainage system. The high surface represents an Early Miocene NE-SW directed palæodrainage, disrupted by Late Miocene. 7 Introduction A’ Kasta o u -4500 Fault North A atolia VAMP profile Ankara 40°N Kız ıl ır ak Tuz Gölü Cappadocia Ma av ga t A talya Kara a Göksu Ada a Mut 30°E Silike 0 75 150 A kilometers Central Anatolia Plateau (CAP) South Ele aio [k ] 40°N 36°N Messaoria Rainfall [mm/yr] 102 36°N Cilicia Basi Kyre ia Ra ge 2 1 Cyprus 0 -1 -2 -3 African Rainfal [mm/yr] 1930 34 °E Sinop Topography a d rai fall s ath profile 3600 2000 0 30 °E 34°E Ele aio [m] Cilicia Basin Tauride Mt s Mut Basin .. .. Tuz Golu Basin Ankara Neogene marine/ co i e tal sedi e ts Black Sea ? ? plate North North Anatolian Fault Po ide Mt s Metamorphic rocks Intrusive rocks 1500 Rainfall 1000 500 Ele aio [ ] 2000 1000 0 Topography -1000 -2000 0 A 100 200 300 400 500 600 700 800 Distance along swath [km] A’ Figure 1.3: Vertical Anatolian Movement Project (VAMP) study area. Slight modification from figures shown in the VAMP proposal [unpublished], showing a schematic geologic section, as drawn by Prof. Dr. Helmut Echtler, Prof. Dr. Andreas Mulch and Prof. Dr. Giovanni Bertotti [unpublished], and the elevation and 1998-2006 precipitation profiles by Dr. Bodo Bookhagen [unpublished]. S N Central Anatolian Plateau EMed Cyprus African mantle lit CTM hosph ere Asthenosphere CPM TGB Eurasian continental crust Eurasian mantle lithosphere Asthenosphere BkS ~200 km Figure 1.4: Schematic representation of the crustal and lithospheric thicknesses in the Central Anatolian Plateau. Extracted and simplified after Stephenson et al. [2004]. Topography-bathymetry is exaggerated three times. For the acronyms see Appendix C. 8 Chapter 1 The high reliefs found in the area, the Taurus Mountains and the Kyrenia Range, must have therefore mostly developed at later stages, effectively dismembering this northeast Mediterranean basin into the modern basins seen in the area (Fig. 1.5). While the growth of the Kyrenia Range occurs in relation to south-verging thrusts [Calon et al., 2005a, b; McCay, 2010], the growth of the Taurus Mountains and that of the SCAP remains enigmatic, with the apparent absence of regional accommodating structures. The present configuration, age, and distribution of the marine sediments in the margin and further south implies that during the Late Tortonian, a change in the vertical kinematics led to the coeval uplift and subsidence of the northern and southern areas of the Miocene basin, respectively. Between these two areas, the Miocene sediments were gently tilted southwards. Accordingly, a N−S section transecting the central area of south Turkey and its offshore area show a Miocene monocline [Çiner et al., 2008]. Onshore subhorizontal sediments at ∼2 km in the Mut Basin and offshore flat-lying deposits at ∼−2 km in the Cilicia Basin are connected by a transitional area, gently south-dipping. Relevant information is preserved in these Miocene marine sediments (Figs. 1.3 and 1.5), such as the youngest age for initiation of the uplift, marked by the disruption of the marine sedimentation in Late Tortonian times [Cosentino et al., 2012], or the type of uplift and the nature of its accommodation structures, registered in the sedimentary architecture of the basins being studied in this Thesis. 1.1.4 Aims of the Thesis This Thesis aims at achieving a deeper understanding on the regional tectonic evolution and formation mechanisms of the CAP-system in relation to that of the Cyprus subduction system, located immediately south of the plateau. More specifically, this contribution intends to quantify and characterize the type of tectonic motions, both in the vertical and in the horizontal directions, and unravel the genetic nature of the CAP by means of fieldwork, structural techniques, basin analyses, and geodynamic modeling. To gain these goals, this Thesis focuses on the SCAP and its onland and offland adjacent regions before and during its growth. Specific goals The specific targets of this Thesis are to (i) determine the structures responsible for the growth of the SCAP, (ii) understand the development of the margin from Miocene to the present, constraining the ages of the main tectonic events, and (iii) propose a regional quantitative model to explain the tectonic and geodynamic evolution of an area stretching from the CAP interior to the Cyprus arc-trench system. i) Recognize the structures behind the formation of the SCAP. The causes driving the tectonics motions in the southern margin of the CAP influence the character, distribution and direction of the tectonic structures accommodating the movements. Recognizing these structures is therefore essential to understand the mechanisms. As two simple possibilities, in the case of the surface uplift, the motion might be accommodated by S-verging thrusts faults or by S-dipping extensional faults, intrinsically implying entirely different uplift mechanisms. 9 Introduction ii) Determine the age of the tectonics events in the SCAP. The spatio-temporal evolution of vertical motions in the margin can be determined by analyzing the geometries of the accommodation structures and the sedimentary growth patterns, as well as by subsidence curves and kinematic reconstructions. ■ ■ iii) Quantitatively understand the evolution of the SCAP in its regional tectonic setting. Quantitative geodynamic modeling is used to understand the largescale tectonic framework during the Miocene to Present evolution of an area between the CAP interior and Cyprus. Constrained by an integration of new and available geologic data, the models provide insights into the thermo-mechanical controls of the■ vertical motions. ■ Z ■ EF 34ºE 36ºE 38ºE ■ Ab AB MB rusEBM ounta ins CB ▲ ▲ ▲ 32ºE Ab Antalya basins MaB Manavgat Basin ▲ ▲ ▲ ▲ ▲ ▲ ge ▲ K ▲yre a R▲an▲ ▲ni▲ 34ºE EB MB ▲ ▲ ▲ ▲ 35º30´N 35º30´N MaB Ta u 36ºN 36ºN 36º30´N 36º30´N ■■ 32ºE ▲ Km 0 36ºE Ermenek Basin Mut Basin 100 200 38ºE AB Adana Basin CB Cilicia Basin Figure 1.5: Map of the Miocene marine basins seen in the SCAP and further south. These basins were formed in a broad subsiding area in the Early Miocene. 1.2 1.2.1 Tectonic setting of Turkey Tectonic plates arrangement and motions Turkey occupies a western position in the Arabian-Eurasian collision zone, which is an extensive region of intracontinental convergent deformation, and represents a transitional area separating a shortening domain in the east (Iran) and an extensional domain in the west (Aegean). Turkey represents an accretionary orogen in which a diachronous collision led to continent-continent collision in its eastern section and an ocean-continent collisional setting in its western section [e.g. Robertson, 2000]. Intracontinental convergent deformation results in the present-day convoluted (macro/micro) tectonic plate puzzle. This complicates the determination of 10 Chapter 1 boundaries and mutual influences amongst the different tectonic plates, and has fomented a long-lasting scientific discussion [e.g. Wortel et al., 2010] (see Fig. 1.6). This discussion is, however, outside the scope of this Thesis. Several tectonic boundaries coalesce in the eastern Mediterranean. The southeastern boundary of the Eurasian Plate in the north, and the northeast limit of the African Plate in the south, merge in the eastern Mediterranean. Since the AfricanEurasian collision, which probably started 30 − 25 Ma [e.g. Jolivet and Faccenna, 2000; McQuarrie and van Hinsbergen, 2013], the African Plate has moved in a counterclockwise manner with velocities ranging from 3,3 mm/y in the west to 10 mm/y in the easternmost Mediterranean [McClusky et al., 2000]. This collision led to a complex subduction area all over the Mediterranean that developed, among others, the Cyprus Arc. To the east of these arc-trench systems, the current northward motion of the Arabian Plate (20 − 24 mm/y) leads to rifting in the Red Sea [McClusky et al., 2000]. Two microplates are generally recognized between the African and the Arabian plates in the eastern Mediterranean, the Sinai and the Anatolian−Aegean microplates. The Sinai Microplate, in the southeasternmost of this collisional area, shears along the Dead Sea Fault to the east and along a diffusive boundary in the western Gulf of Suez, creating the Sinai peninsula. The Sinai Block moves northward relative to the African Plate at ∼1,4 − 2,4 mm/y [Wdowinski et al., 2004; Mahmoud et al., 2005]. The Cyprus Arc-trench System bounds the Sinai Block to the north, where it comes in contact with the Anatolian−Aegean Microplate. The Cyprus Arc, active since the Early Miocene [e.g. Robertson, 2000; Stephenson et al., 2004], presently accommodates convergence by frontal accretion at velocities between 18 mm/y (in the west) and 9 mm/y (in the east) [Reilinger et al., 2006]. The CAP develops in a northward position, within the Anatolian−Aegean Microplate. The Anatolian−Aegean Microplate rotates counterclockwise, while moving W to SSW as it is extruded from the Arabian−Eurasian collision zone along the right-lateral North Anatolian Fault Zone (NAFZ) and the left-lateral East Anatolian Fault Zone (EAFZ). The rates increase in a westward direction from 20 mm/y in Central Anatolia to 30 mm/y in the Hellenic trench [Jiménez-Munt et al., 2003]. This westward extrusion is also driven by slab pull in the Aegean region [Jiménez-Munt et al., 2003]. At present, the Hellenic Arc is affected by arc-parallel extension while SSW-directed extension affects the Aegean-West Anatolian region [Hatzfeld, 1999]. 1.2.2 Tectonic slabs In the eastern Mediterranean, the African slab sinks under the European lithosphere. Remnants of the Neotethys Ocean presently appear as a broken slab beneath the Iranian Plateau [e.g. Keskin, 2003], subducting northwards along the Cyprus arctrench system under the Anatolian region [e.g. Bakırcı et al., 2012], maybe partially breaking-off, and as a retreating slab in the Aegean [e.g. Jolivet, 2001]. Differential motions of the slab and tearing create a variety of shapes, geometries and processes that strongly influence the upper crustal deformation mechanisms. Seismic tomography studies show a slab detachment beneath eastern Anatolia, with a slab remnant separated from the lithosphere and presently seen at ∼600 km [Piromallo et al., 2003; Faccenna et al., 2006; Hall et al., 2009] (see Fig. 1.7). Introduction 11 Figure 1.6: Simplified tectonic map of the eastern Mediterranean Sea and surrounding regions. The original compilation by Aksu et al. [2005a] is slightly modified here to include the position of the marine Oligo-Miocene basins (grey) in the south of the CAP and Cyprus. Figure 1.7: 3-D diagram of the resolved segmented geometry of the subducting African lithosphere beneath Anatolia inferred from Biryol et al. [2011] tomographic model, as seen in their contribution. 12 Chapter 1 The detachment of the African slab caused the uplift in the East Anatolian Plateau [e.g. Keskin, 2003] and is presumably related to the activation of the NAFZ [Faccenna et al., 2006] and the EAFZ. This model would imply relevant subsidence in the center of the SCAP (Mut area), contrary to the observed uplift. The activation of the sinistral EAFZ might be linked with the disruption and tearing of the subducting slab below the northeasternmost Mediterranean coast [Govers and Wortel, 2005; Biryol et al., 2011] and the volcanism seen in SE Anatolia [Arger et al., 2000]. Further to the west, the African slab seems to be attached [Faccenna et al., 2003; Biryol et al., 2011; Bakırcı et al., 2012] and reaches relevant depths in the Cyprus and Hellenic arcs, where it has been imaged at a depth of ∼1500 km [Wortel and Spakman, 2000]. Yet another relevant slab tear is seen separating the Hellenic and the Cyprus slabs [Faccenna et al., 2006; Biryol et al., 2011]. 1.2.3 Temporal evolution Starting in Cretaceous times, the evolution of the area has been controlled by the northward subduction of the northern side of the Neotethys Ocean. This process led to collision of several northward-drifting continental fragments [e.g. Şengör and Yılmaz, 1981; Görür et al., 1984; Williams et al., 1995; Robertson, 1998b; Okay and Tüysüz, 1999; Hüsing et al., 2009; Pourteau et al., 2010, 2013a] (see Fig. 1.8). Following the ocean closure, a possible delamination-induced event in the Eocene epoch is recorded by related magmatism [Kadioglu and Dilek, 2010]. These events occurred before the time-span considered in this Thesis, and will not be discussed in any detail. The initial formation of relief in both the Pontides by Eocene times [e.g. Şengör and Yılmaz, 1981] and the Taurides by Early Oligocene [e.g. Jaffey and Robertson, 2005; Eriş et al., 2005], is shown by the absence of Upper Palæogene and non-marine deposition in the north [e.g. Robinson et al., 1995] and terrestrial sedimentation in the south [e.g. Bassant et al., 2005; Şafak et al., 2005] by Oligocene to Early Miocene time. This continental deposition is broadly contemporaneous with the Cyprus arc activation during the Early Miocene [e.g. Robertson, 2000; Stephenson et al., 2004] and the initiation of E−W extension in Central and West Anatolia [Whitney and Dilek, 1997]. Continued variable extension in both Central and West Anatolia may be linked with the westward escape of Anatolia, which probably commenced during the Middle Miocene (∼17 My or earlier times). The extrusion tectonics led to up to 40◦ clockwise rotation in the west by ∼15 − 8 My, and possibly accelerated subduction during latest Miocene-Pliocene times ∼5 My [Armijo et al., 1996, 1999; Jolivet and Patriat, 1999; Van Hinsbergen et al., 2005]. The tectonic escape of Anatolia was facilitated by the activation of the main transpressional structures observed today in the North Anatolian Fault Zone (NAFZ) and the East Anatolian Fault Zone (EAFZ), probably in relation to the detachment of the slab in east Anatolia [Faccenna et al., 2006]. Although highly debated, activation of the main transform faults is assumed as Middle Miocene for the NAFZ [e.g. Şengör et al., 2005] and latest Miocene for the EAFZ [e.g. Robertson, 2000]. 13 Introduction 32ºE A 36ºE Sinop ISTANBUL ZONE Boyabat 40ºN 40ºN Istanbul zmir 40ºE Kastamonu e Suture Intra-Pon t i d SAKARYA ZONE Çankιrι Ankara Eskişehir ir-Anka r a S uture İzm e Inne r-Ta ur 38ºN Bi t l i s - Z Ermenek ARABIAN PLATFORM Adana Mut ture Su os r ag 36ºN 36ºN Kayseri Karaman Antalya 38ºN Aksaray Konya Aydιn re Erzincan re KIRŞEHIR utu MASSIF d S i Kιrşehir MENDERES-TAURUS BLOCK ut u Ankara-Erzin c an S Mersin 34ºN 34ºN 40ºE Km 0 32ºE Faults ■ ■ ■ Normal faults ▲ ▲▲ Thrust faults Strike-slip faults 100 200 300 36ºE E(CA)FZ EKT KMATZ LFZ Marine Miocene Basins East Anatolian Fault Zone North Anatolian Fault Zone Tüz Gölu Fault Zone EAFZ NAFZ TGF 32ºE Ecemis (Central Anatolian) Ekinveren Thrust Kyrenia-Misis-Adrın Thrust Levanine Fault Zone 36ºE B 40ºE Sinop ▲ ▲ ▲ ▲ ▲ ▲ 40ºN EKT 40ºN Istanbul PONTIDES zmir N AF Z Çankιrι Ankara AL R T N E ANAC TOLI A ■ ■ ■ ■ ▲ ▲ L Z Antalya TAURIDES Ermenek ▲ K ▲ ▲ ▲ ▲ ▲ ▲ ▲ 40ºE Km ▲ 34ºN 32ºE ▲ ▲ ▲ 34ºN ▲ Adana Mersin M AT Z ▲ ▲ Mut L FZ ■ ■ EA F ■ ■ 36ºN Aksaray 36ºN N Konya ▲ ■ ■ ■ ■ ■ Kayseri ■ ■ ■ ■ ■ ■ ■ ■ 38ºN ■■ ■ ■ ■ ■ ■■ ■ ■ ■ ■ ■ Aydιn ■ ■ ■ ■ ■ ■ F TG ■ ■ Z EF 38ºN ■ Erzincan Z) (C Kιrşehir ■ ■ AF Eskişehir ▲ ▲ 0 100 200 300 36ºE Figure 1.8: Map A depicts the main palæoterrains/microcontinents and suture zones of Turkey. A slight modification on the location of the boundaries shown by Okay and Tüysüz [1999] is based on the analysis of 1 arc DEM and LandSat 7 images set from NASA. Map B shows the main regional faults of Turkey. 14 Chapter 1 The Eratosthenes Seamount must also be considered to complete the tectonic picture of the east Mediterranean. This continental fragment drifted northward on top of the Levantine oceanic (or thinned continental) crust [e.g. Rabinowitz and Ryan, 1970; Woodside, 1977; Makris and Stobbe, 1984] and collided with the Cyprus arc-trench system in Messinian times [e.g. Stephenson et al., 2004]. Southward overthrusting of the Cyprus margin drove crustal flexure and tectonic subsidence in the lower plate and rapid surface uplift of the Troodos Ophiolite on the upper plate, and perhaps in southern Turkey, by Late Pliocene-Early Pleistocene times [e.g. Robertson, 1998b; Schildgen et al., 2012a]. This collision slowed or even locked subduction in southern Cyprus. 1.3 Structure of the Thesis In this Thesis, a variety of approaches have been used, ranging from fieldwork and finite element thermo-mechanical modeling to seismic interpretation, backstripped subsidence curves, and kinematic and palinspastic restorations. A detail explanation of the methods used is given in Chapter 2. Chapter 3 aims at constraining the tectonic evolution of the interior of the CAP before and during its uplift. In Chapter 3, seven depth-converted seismic reflection profiles and the analysis of backstripped subsidence curves, isochore maps, and a palinspastically restored cross section are used, and a new 3D tectonic model is proposed for the Cenozoic evolution of the Tuz Gölü Basin and surroundings. Chapter 4 deals with the Miocene evolution of the Manavgat, Ermenek-Mut, and West Adana basins. Here, fieldwork, structural data and subsidence analysis allows for the reconstruction of the present day architecture of the basins capping the SCAP. These studies shed light on the mode of deformation and the type and time of vertical motions in the margin. In Chapter 5, three offshore depth-converted seismic reflection sections and onshore fieldwork constraints were used to unravel the evolution of the transitional area between the Mut Basin and Cilicia Basin in its regional context. The seismic data is linked to the data from the northern and southern onshore areas to analyze the vertical motions and kinematic history of the area, and the formation of the southern margin of the Central Anatolian Plateau in relation to the Northeast Mediterranean tectonics. The newly acquired structural and basin analysis data is finally integrated with previous studies and tested in coupled finite element thermo-mechanical models in Chapter 6. The models successfully reproduce the vertical tectonic history, presentday geometries, and major structures seen in the area, thus providing a valid alternative to explain the SCAP tectonic evolution through time, while questioning the detachment and slab break-off theories. The proposed mechanism relates the evolution of the area and the Central Anatolian Plateau formation to the onset of subduction in a position similar to present day, and the posterior growth of the Anatolian upper plate and that of its associated forearc basin system. A final overview of the work presented in this Thesis and its placement in a broader scientific context is given in Chapter 7. 15 Introduction Study area 7 as E ter Chapter 3 ap Ch Turkey tM ed i te r ra n e a n Ch a pte Syria Chapter 5 r4 Lebanon East Mediterranean Chapter 6 Cyprus Figure 1.9: Map of the eastern Mediterranean and its onland areas, showing the areas covered by each individual chapter of this Thesis. The base map used comes from the morpho-bathymetric map of the Mediterranean [Loubrieu, B. and Mascle, J., 2008]