Imaging of subsurface lineaments in the southwestern part of the Thrace Basin from gravity data

Linear anomalies, as an indicator of the structural features of some geological bodies, are very important for the interpretation of gravity and magnetic data. In this study, an image processing technique known as the Hough transform (HT) algorithm is described for determining invisible boundaries and extensions in gravity anomaly maps. The Hough function implements the Hough transform used to extract straight lines or circles within two-dimensional potential field images. It is defined as image and Hough space. In the Hough domain, this function transforms each nonzero point in the parameter domain to a sinusoid. In the image space, each point in the Hough space is transformed to a straight line or circle. Lineaments are depicted from these straight lines which are transformed in the image domain. An application of the Hough transform to the Bouguer anomaly map of the southwestern part of the Thrace Basin, NW Turkey, shows the effectiveness of the proposed approach. Based on geological data and gravity data, the structural features in the southwestern part of the Thrace Basin are investigated by applying the proposed approach and the Blakely and Simpson method. Lineaments identified by these approaches are generally in good accordance with previously-mapped surface faults

Tectono-stratigraphical evolution of the Çankırı Basin (Central Anatolia, Turkey)

The Izmir-Ankara-Erzincan Suture Zone (IAESZ) demarcates the former position of the northern Neotethys ocean. Along the IAESZ, the Rhodope-Pontide fragments and Taurides collided and amalgamated in the Early Tertiary, leaving behind a number of basins with a thick in-fill that was accumulated during the subduction and collision processes. The Çankırı Basin is one of the largest of such Tertiary basins in Turkey and is located within the IAESZ. It is a unique area to study the subduction and collisionary processes and post-collisional history of central Anatolia, owing to a nearly complete sedimentary record from Late Cretaceous to Recent. This thesis presents an integrated stUdy concerning the Late Cretaceous to Recent tectono-stratigraphical evolution of the Çankırı Basin using stratigraphical studies, structural geology, kinematic analysis, paleomagnetic studies, 3D modeling, seismic interpretation and gravimetric analysis

Kinematic and structural development of the Cankiri basin, central Anatolia, Turkey : a paleostress inversion study

Three different deformation phases have been recognized in the southern part of the Cankin Basin from (1) the major structures and (2) through using paleostress inversion techniques for fault slip data. The deformation phases recognized from the paleostress data are correlated with those recognized from the major structures and dated accordingly. The first phase occurred in the Late Paleocene to pre-Burdigalian and is characterized by an oblique sigma(2) and NNE-SSW to NE-SW trending subhorizontal sigma(1) and WNW-ESE to NW-SE trending sigma(3) patterns which indicate transcurrent deformation associated with a combination of thrusting and strike slip faulting (transpression) possibly due to indentation of the Kirsehir Block to the Sakarya Continent. The second phase occurred from the Burdigalian to the Serravallian and is characterized by a subvertical sigma(1) and oblique sigma(2) and sigma(3), which indicate oblique extension associated with normal faulting possibly due to a post-orogenic collapse. The third deformation phase is characterized by a vertical 92 while the other stresses were horizontal, which indicate regional transcurrent tectonics, which is correlated with the current transcurrent tectonics controlled by the North Anatolian Fault Zone. (C) 2003 Elsevier Science B.V. All rights reserved

Tectono-stratigraphy of the Çankiri Basin: Late Cretaceous to early Miocene evolution of the Neotethyan Suture Zone in Turkey

The Çankırı Basin straddles the İzmir–Ankara–Erzincan Suture Zone which demarcates the former position of the northern branch of the Neotethys. It includes more than 3 km of pre-Middle Miocene in-fill related to late Cretaceous to pre-Middle Miocene evolution of the region. The basin has developed on the upper Cretaceous subduction complex and arc related basins of the Neotethys Ocean. The basin fill includes an upper Cretaceous forearc sequence overlain by Paleocene with a local unconformity. The upper Cretaceous configuration of the Çankırı basin is interpreted as a part of a forearc basin. The Paleocene and younger history is interpreted as a foreland sequence dominated by progressively southwards migrated depocenters in front of southward migrating thrust faults upon which a series of piggy-back basins were developed. Termination of the forearc setting and beginning of foreland basin conditions indicates complete subduction of the Neotethyan oceanic crust and onset of collision between the Pontides (Laurasia) and the Taurides (Gondwana) in the Paleocene. Thrusting and related sedimentation continued until the Aquitanian (Early Miocene

Late Cretaceous extensional denudation along a marble detachment fault zone in the Kırşehir massif near Kaman, central Turkey

In the Central Anatolian Crystalline Complex (CACC), 100 km scale metamorphic domains were exhumed in a context of north-south plate convergence during late Cretaceous to Cenozoic times. The timing, kinematics and mechanisms of exhumation have been the focus of previous studies in the southern Ni gde Massif. In this study, we investigate the unexplored northern area regarding the tectonic features preserved on the edges of the Kırs¸ ehir Massif, based on detailed field-mapping in the Kaman area where high-grade metasediments, non-metamorphic ophiolites and monzonitic plutons are locally exposed together. Close to the contact with the ophiolites, west-dipping foliated marble-rich rocks display mylonites and discrete protomylonites with normal shear senses indicating a general top-to-the WeNW direction. Both of these structures have been brittlely overprinted into cataclastic corridors parallel to the main foliation. The mylonite series and superimposed brittle structures together define the Kaman fault zone. The study of the evolution of calcite deformation fabrics along an EW section supported by Electron Back Scattered Diffraction measurements (EBSD) on representative fabrics indicates that the Kaman fault zone represents an extensional detachment. In Ömerhacılı, in the vicinity of the Baranada g quartz-monzonite, the metamorphic sequence shows static annealing of the calcite mylonitic fabrics. This evidence suggests that intrusion took place at shallow depth (w10 km) into an already exhuming metamorphic sequence. As a consequence for the Kaman area, buried metasediments have been rapidly exhumed between 84 and 74 Ma (w1 km/Ma) where exhumation along a detachment zone, displaying a top-to-theWeNW shear motion, took place in the mid to upper crust prior to magmatic intrusion in the late Campanian. As the intrusion cut through the detachment fault, the main shearing deformation ceased. Brittle tectonics coupled with erosion likely took over during the final unroofing stages at a slower rate (<0.2 km/Ma), until the pertinent rocks reached the Earth’s surface in the late Paleocene