Sedimentary development of the Oligocene Karsanti Basin, southern Turkey, in its regional tectonic setting

Following Late Cretaceous ophiolite and melange emplacement within the Tauride belt several Neogene sedimentary basins of variable size were formed along the southern flank of the Taurus continent in southern Turkey. These include the Pozanti and Karsanti Basins and the regional scale Çukurova Basin Complex, extending southwestwards into the Cilicia-Kyrenia Basin. The Karsanti Basin is bounded by the regional scale sinistral Ecemiş Fault Zone to the west, the East Anatolian Fault Zone to the southeast and the Negoene Adana Basin to the south. Deformed Palaeozoic and Mesozoic rock units that display an irregular palaeotopography form the basement of the Karsanti Basin. These units are overlain by an allochthonous Kizildağ melange and by thrust slices of basic/ultrabasic ophiolitic rocks (Faraşa ophiolites) that were emplaced in this region during the Late Maastrichtian. The Karsanti Basin was formed during the Oligocene above the thrust sheets. The Karsanti Basin disconformably overlies the ophiolitic nappes and is interpreted as a N-S trending half graben which was probably most active following the deposition of lacustrine sediments during the late Oligocene. The main Karsanti Basin infill is represented by four lithological units: 1. Alluvial fan deposits (A1), 2. shallow-marine deposits (A2), 3. lacustrine deposits (A3), and 4. fluvial deposits (A4). These sediments were deposited during the Oligocene, prior to the initiation of the main Adana Basin, which formed in a separate intermontane setting. The Karsanti Basin fill is unconformably overlain by early Miocene sediments of the Neogene Adana basin. © 2015 Elsevier Ltd

Late Cretaceous–Cenozoic subduction–collision history of the Southern Neotethys: new evidence from the Çağlayancerit area, SE Turkey

Evidence of the subduction–collision history of the S Neotethys is well exposed in the frontal part of the SE Anatolian thrust belt and the adjacent Arabian continental margin. The foreland succession in the study area begins with Eocene shelf carbonates, ranging from shallow marine to deeper marine, without sedimentary input from the Tauride continent to the north. After a regional hiatus (Oligocene), sedimentation resumed during the Early Miocene with terrigenous gravity-flow deposition in the north (Lice Formation) and shallow-marine carbonates further south. Clastic detritus was derived from the Tauride continent and oceanic accretionary material. The base of the overriding Tauride allochthon comprises ophiolite-derived debris flows, ophiolite-related mélange and dismembered ophiolitic rocks. Above this, the regional-scale Bulgurkaya sedimentary mélange (an olistostrome) includes blocks and dismembered thrust sheets of metamorphic rocks, limestone and sandstone, which include Late Cretaceous and Eocene foraminifera. The matrix is mainly strongly deformed Eocene–Oligocene mudrocks, hemipelagic marl and sandstone turbidites. The thrust stack is topped by a regionally extensive thrust sheet (Malatya metamorphic unit), which includes greenschist facies marble, calcschist, schist and phyllite, representing Tauride continental crust. Beginning during the Late Mesozoic, the S Neotethys subducted northwards beneath a backstop represented by the Tauride microcontinent (Malatya metamorphic unit). Ophiolites formed within the S Neotethys and accreted to the Tauride active margin. Large-scale sedimentary mélange developed along the Tauride active margin during Eocene–Oligocene. On the Arabian margin, a sedimentary hiatus and tilting (Oligocene) is interpreted to record initial continental collision. The Early Miocene terrigenous gravity flows represent a collision-related flexural foreland basin. Southward overthrusting of the Tauride allochthon took place during Early-Middle Miocene. Associated regional uplift triggered large-scale alluvial deposition. The foreland folded and faulted in response to suture zone tightening (Late Miocene). Left-lateral strike slip characterised the Plio-Pleistocene. © 2015, Springer-Verlag Berlin Heidelberg

Tectonic and sedimentary evolution of the Cenozoic Hatay Graben, Southern Turkey: A two-phase model for graben formation

New structural and sedimentary studies form the basis of a new interpretation for the Neogene Hatay Graben. Fault analysis reveals three contemporaneous trends of fault orientation (000°-180°, 045°-225° and 150°-350°) suggesting that the graben is transtensional in nature. Sedimentary studies show that, following shallow-marine deposition from the Late Cretaceous to the Eocene, a hiatus ensued until Early Miocene fluvial sedimentation. After a Mid-Miocene marine transgression, water depths increased until the Messinian salinity crisis, followed by a regression from the Pliocene to the present day. The basin initially developed as the distal margin of a foreland basin of the Tauride allochthon to the north, developing a classic sedimentary sequence during Mid-Late Miocene. Stresses caused by loading of the crust created a flexural forebulge to the south that supplied sediment mainly northwards. During the Plio-Quaternary, transtensional graben development took place, primarily influenced by the westward tectonic escape of Anatolia along the East Anatolia Fault Zone and left-lateral offset along the northward extension of the Dead Sea Transform Fault. This area is, thus, an excellent example of a foreland basin reactivated in a strike-slip setting. Our new two-phase model: foreland basin, then transtensional basin for the Hatay Graben, is in contrast to previous models, in which it was generally assumed that the Plio-Quaternary Hatay Graben represents a direct extension of the Dead Sea Fault Zone or the East Anatolian Fault Zone. © The Geological Society of London 2006

Quaternary stress regime change in the Hatay region (SE Turkey)

In this study we determine the Plio-Quaternary to present-day stress regime acting in the Hatay region located at the northeastern corner of the East Mediterranean region. The modern state of stress is obtained from inversion of focal mechanism solutions of shallow earthquakes. This inversion identifies a dominantly extensional stress regime with a NE-trending ?Hmin (?3) axis at the present-day. The stress regime determined from inversion of slip-vectors measured on fault planes confirms that this regime is extensional in the studied area. Both the kinematics and chronologies of fault slip-vectors show that the stress state changed from an earlier strike-slip regime to a younger extensional stress regime with a consistent NE-trending ?Hmin (?3) axis. The change from strike-slip to extensional stress regimes probab y occurred during the Quaternary. Regionally, both stress regimes induce sinistral displacement on the East Anatolian Fault and Dead Sea Fault systems. The North Anatolian Fault (NAF) is a dextral strike-slip fault which runs about 1400 km from east to west and has been active since collision between the Eurasian and Arabian plates. Together with the sinistral East Anatolian fault, the NAF intracontinental deformation zone contributes to the westward extrusion of Anatolia as a consequence of northward drift of Arabia. Consequently, the Late Cenozoic stress regimes acting in the Hatay region result from the coeval influence of forces due to: (1) the subduction processes in the west and southwest; (2) the continental collision in the east, and (3) the westward escape of the Anatolian Block. However, the timing of the temporal stress transition suggests that the Quaternary stress regime change resulted from subduction processes with the extensional stress regime in the Hatay region being mainly attributable to roll-back of the Mediterranean subducted slab along the Cyprus Arc

Geochemistry of Pliocene/Pleistocene basalts along the Central Anatolia Fault Zone (CAFZ), Turkey

Pliocene - Pleistocene volcanism accompanied strike-slip-related transtensional deformation along the Kizilirmak fault segment of the Central Anatolian fault zone (CAFZ) in the west of Sarkişla (Sivas-central Turkey). These volcanic rocks are represented by alkali olivine basalts. They can be divided into four different sub-groups on the basis of their Zr, Nb, TiO2 contents. A primitive mantle-normalized incompatible trace element diagram for four subgroups shows close similarity to typical OIB pattern. Some of the incompatible trace element ratios (Ce/Y, Zr/Nb, La/Ba, La/Nb) are also akin to OIB values. Highly fractionated REE patterns (La/YbN=24.7-9.2) with no Eu anomaly are the main features of the alkali basalts and are comparable to alkaline volcanism in continental rift zones. On the basis of Al2O3/TiO2, Nb/Y, Zr/Nb ratios, the geochemical differences among four sub-groups can be explained by variable degrees of partial melting of compositionally similar mantle source. Th/Nb, Th/Y, Nb/Y ratios and the primitive mantle-normalized trace element diagram suggests significant amount of crustal involvement for most of the alkali olivine basalts erupted along the CAFZ. Rupture of the continental lithosphere by strike-slip-related transtensional deformation might have caused decompressional partial melting of the asthenospheric mantle and generating alkali olivine basalts in this region. © 2001 Éditions scientifiques et médicales Elsevier SAS.MMF.2000.46The financial support to conduct field work was provided by Çukurova University Research Foundation (Project number: MMF.2000.46). Mahmut Eroğlu is greatly acknowledged for his help during field study. Authors thank Fabio Capponi for performing major and trace element as well as Pia Voldet for REE analyses. We are grateful to Volker Höck and Peter Floyd for their valuable comments and suggestions concerning our manuscript

Tectonostratigraphic evolution of the upper cretaceous-cenozoic central anatolian basins: An integrated study of diachronous ocean basin closure and continental collision

The Upper Cretaceous-Mid-Eocene Kirikkale, Tuz Gölü, Haymana and ç ankiri basins are bounded by the Pontide (Eurasian) continental margin to the north, the Nig`de-Kirşehir microcontinent to the east and the Tauride-Anatolide continental unit to the south. The basins developed during northward subduction/collision of theÌzmir-Ankara-Erzincan Ocean ('northern Neotethys') in the north and the inferred Inner Tauride Ocean in the south. Subduction of the Ìzmir-Ankara-Erzincan Ocean resulted in latest Cretaceous collisionof the Nig`de-Kirşehir microcontinent with the Pontide active margin and ophiolite emplacement. Some mid-ocean ridge-type oceanic crust remained to the SW and formed the basement of the Kirikkale and Tuz Gölü basins. These basins are partially floored by an accretionary wedge to the west and by the Nig`de-Kirşehir microcontinent to the east. Locally volcaniclastic, the sediment infill switched to terrigenous after latest Cretaceous. The Haymana Basin, further NW, developed as a forearc basin on the Mesozoic accretionary wedge and Pontide continental fragments. The çankiri Basin also developed on an accretionary wedge, bounded by the Eurasian active margin to the north. An extensional setting prevailed during the latest Cretaceous related to subduction of remnant oceanic crust, followed by a switch to regional compression during Late Paleocene-Mid Eocene progressive and diachronous collision. © The Geological Society of London 2013

Late Cenozoic stress state distributions at the intersection of the Hellenic and Cyprus Arcs, SW Turkey

The history of the Late Cenozoic stress regime was determined for an area between the gulfs of Fethiye and Antalya. Fault kinematic analysis and inversion of focal mechanisms of shallow earthquakes reveal significant evolution of the regional stress regime in SW Anatolia, i.e., the area of interaction between the Hellenic and Cyprus arcs, from the Mio-Pliocene to the present time. Fault kinematic analysis yields two different normal faulting stress regimes along the southwestern part of Fethiye-Burdur Fault zone, e.g., in and around Çameli Basin (Zone A1) and two different strike-slip to normal faulting stress regimes characterized by a roughly orthogonal set of extensional axes between Fethiye and Demre (Zone B) with an older NW–SE ?3 axis for Mio-Pliocene and a younger NE–SW ?3 axis for Plio-Quaternary time. Inversion of focal mechanisms of the earthquakes occurring in Zone A1 provides an extensional stress state with approximately N-S ?3 axis. Inversion of those occurring in Zone B, south of Zone A1, yields a dominantly strike-slip stress state with a NE-SW ?3 axis and a NW-SE ?1 axis respectively. The inversion slip vectors from fault planes yield a consistent normal faulting stress regime in Burdur Basin and its surroundings (i.e., along the northeastern part of Fethiye-Burdur Fault Zone, (Zone A2)) during Plio-Quaternary, continuing into recent time as indicated by earthquake focal mechanism inversions. Both states have a consistent NW–SE ?3 axis. Fault kinematic analysis indicates NW-SE extension acting in Zone C (subarea between Demre and Antalya), south of Zone A2, during Mio-Pliocene time. The inversion of focal mechanisms yields normal faulting also characterized by a consistent NW-SE ?3 axis. The nearly orthogonal extensional stress regimes (NW-SE and NE-SW) obtained by inversion of both measured and seismic faults seem to have been acting contemporaneously with each other at different intensities from the Mio-Pliocene onwards in SW Turkey. This may be attributed to the geodynamic effects related to the subduction of the African plate beneath Anatolia diffusing along the Hellenic and Cyprus arcs and in the west-southwestward extrusion of Anatolia. The cause of the early NW–SE extension is the slab-pull force due to the subduction process along the Cyprus arc, considered to be dominant until the Plio-Quaternary in the western part of the study area in zones A1 and B. The dominant status of the Cyprus arc continues today in the eastern part of study area in zones A2 and C. The later NE–SW to present day approximately N–S extension, dominant since the Plio-Quaternary, is related to the combined forces of the Anatolian extrusion and the subduction process along the Hellenic arc. © 2016 Elsevier Ltd107Y321This work was financially supported by TUBİTAK-ÇAYDAG (Project no: 107Y321 ). The authors would like to thank Catherine Yiğit for assistance with English that improved a recent version of the text. The authors are also grateful to the two anonymous reviewers for their valuable comments and suggestions that greatly improved the quality of the manuscript

Plio-Quaternary Stress State in the Burdur Basin, SW-Turkey

This study defines the Plio-Quaternary to present day stress regime in the Burdur Basin, located at the northeastern end of the Fethiye-Burdur Fault Zone in SW Turkey. This fault length, which is considered the landward continuation of the Pliny-Strabo trench, is an important feature in SW Turkey. The inversion slip vectors measured on fault planes indicate a consistent normal faulting stress regime during Plio-Quaternary time, continuing into recent times as indicated by earthquake focal mechanism inversions. Both states have consistent NW-SE trending horizontal minimum stress axes (?3). The orientation of fault sets is predominantly around the NE-SW direction in the major Fethiye-Burdur Fault Zone, making the extension NW-SE. The mean stress ratio is 0.74 indicating a triaxial stress state, which is clearly different from radial extension. The NW-SE extension is probably responsible for the formation of the Burdur Basin during Plio-Quaternary time. This extension, which is probably caused by slab-pull force due to the subduction process along the Cyprus arc, produces a dominant normal motion along the FBFZ. © 2013 Elsevier B.V.107Y321This work was financially supported by TUBITAK-ÇAYDAG (Project no: 107Y321 ). The authors would like to thank Catherine Yiğit for assistance with English exposition that improved recent version of the text. The authors are also grateful to the anonymous reviewers for their valuable comments and suggestions that greatly improved the quality of the manuscript

Erratum to "The Berit transect of the Tauride thrust belt, S Turkey: Late Cretaceous-Early Cenozoic accretionary/collisional processes related to closure of the Southern Neotethys" [Journal of Asian Earth Sciences 27 (2006) 108-145] (DOI:10.1016/j.jseaes.2005.02.004)

[No abstract available

Upper crust response to geodynamic processes beneath Isparta Angle, SW Turkey: Revealed by CMT solutions of earthquakes

The Isparta Angle is an important area of SW Anatolia where extensions in all directions (N-S, NE-SW, NW-SE and E-W) meet. These extensions were determined by normal faulting structures as well as by shallow earthquakes. All extensions, except the E-W one, were attributed to the deviatoric stresses in relation to slab forces and/or extrusion of Anatolia. The moment tensor inversion of 40 shallow earthquakes which occurred in the inner part of the Isparta Angle give focal mechanisms mostly indicating normal faulting. Inversion of all focal mechanisms of the earthquakes obtained from the moment tensor inversion yields normal faulting characterized by an approximately E-W (N268°E) ?3 axis. The calculated stress ratio R is 0.6944 indicating a triaxial stress state. Commonly accepted geodynamic models for the eastern Mediterranean region do not include plate boundary forces acting in the east or west direction. Our hypothesis is that the cause of the E-W extension is the combined forces of Gravitational Potential Energy and the hot asthenosphere upwelling through a tear fault in the subducted African plate between the Hellenic and Cyprus arcs beneath the Isparta Angle. © 2016 Elsevier B.V.107Y321This work was financially supported by TUBİTAK-ÇAYDAG (Project no: 107Y321 ). The authors would like to thank Catherine Yiğit for assistance with English that improved a recent version of the text. The authors are also grateful to the anonymous reviewers for their valuable comments and suggestions that greatly improved the quality of the manuscript