Browsing by Author "Uzel, Bora"

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Age and Kinematics of the Burdur Basin: Inferences for the Existence of the Fethiye Burdur Fault Zone in Sw Anatolia (Turkey)
(Elsevier, 2018) Ozkaptan, Murat; Kaymakci, Nuretdin; Langereis, Cor G.; Gulyuz, Erhan; Ozacar, A. Arda; Uzel, Bora; Sozbilir, Hasan
The Burdur Basin is a late Miocene to Pliocene fluvio-lacustrine basin in SW Anatolia. It is developed within the postulated Fethiye-Burdur Fault Zone, which was argued to be a sinistral strike-slip fault zone developed in response to propagation of the Pliny-Strabo STEP fault into SW Anatolia (Turkey). In order to assess the presence and tectonic characteristics of the fault zone, we conducted a paleomagnetic study in the Burdur basin that involved rock magnetic experiments, Anisotropy of Magnetic Susceptibility (AMS) measurements and developing a magnetostratigraphy for dating purposes. The obtained age model constrains most part of the tectonic evolution of the basin. The well exposed (similar to 270 m thick) Burdur section revealed 3 normal and 2 reverse polarity magnetozones. We propose that the Burdur Formation spans most of the Gauss Chron (similar to 3.4-2.5 Ma) which implies a sedimentation rate of > 18 cm/kyr. The AMS results in the section indicate NW-SE directed extension. In addition, we have also conducted kinematic analyses from 1790 fault slip data collected at 44 sites distributed within the supposed Fethiye Burdur Fault Zone in the region. The results indicate that the region has been developed under a NW-SE directed extensional deformation regime and was dominated by NE-SW striking normal faults from late Miocene to recent. Few NW-SE striking normal faults with strike-slip components are categorized as transfer faults, which accommodated differential stretching between the Burdur and Cameli basins. Stretching amounts increase southwards demonstrating a dextral transtensional character of the transfer faults. We have not observed any significant strike-slip motion along the NE-SW striking faults, which challenges the presence and sinistral transcurrent nature of the supposed Fethiye Burdur Fault Zone.
Deformation in Sw Anatolia (Turkey) Documented by Anisotropy of Magnetic Susceptibility Data
(Amer Geophysical Union, 2021) Ozkaptan, Murat; Gulyuz, Erhan; Uzel, Bora; Langereis, Cor G.; Ozacar, A. Arda; Kaymakci, Nuretdin
Convergence between the Eurasian and the African plates in the West Anatolian-Aegean region results in a trench retreat due to slab roll-back and tearing of the subducted African lithosphere. The upper plate response of this process gave way to back-arc extension in the region. We have conducted a very detailed anisotropy of magnetic susceptibility (AMS) study on the Neogene rocks in SW Anatolia to unravel the style and magnitudes of deformation. For this purpose, from 83 sites in 11 structurally homogeneous domains, 1,680 paleomagnetic samples were analyzed. The results show that AMS fabrics are related to the tectonic deformation and that the magnetic lineation (maximum susceptibility axis, k(1)) is parallel to inferred maximum extension, while minimum susceptibility (k(3)) is typically normal to the bedding plane, corresponding to a preserved compaction associated with deposition fabric. The intermediate axis (k(2)) is parallel to a second extension direction and indicates that the region has been under the control of multi-directional extension during the Neogene. Two main magnetic lineation directions are identified and represent Oligocene to middle Miocene E-W, and late Miocene to Pliocene NW-SE oriented extension. The magnetic lineation directions are dominantly parallel or perpendicular to the general strikes of the normal faults. The results show that the deformation in the region resembles two differentially stretched rubber sheets under the influence of SW oriented extension, exerted by the southward retreating Eastern Mediterranean subduction system.
Middle Pleistocene Tectonic Events Around the SE Aegean Sea: Insights From Magnetostratigraphy, (U-Th)/He Zircon Dating, and Fault Kinematics in the Datca Graben (SW Turkiye)
(Nature Portfolio, 2025) Ince, Meryem Dilan; Kaymakci, Nuretdin; Langereis, Cor; Uzel, Bora; Gulyuz, Erhan; Koralay, Ersin O.; Sumer, Okmen
This study constrains the stratigraphy, age, and tectono-sedimentary evolution of the Datca Graben (southwestern Turkey) through integrated magnetostratigraphy, zircon (U-Th)/He geochronology, sedimentological analysis, and fault kinematic studies. The basin, developed along the southwestern margin of Anatolia under N-S extension, preserves similar to 350 m of fluvio-lacustrine to shallow-marine deposits, primarily assigned to the Yildirimli Formation. Two interbedded tuff layers yield zircon (U-Th)/He ages of 1.56 +/- 0.10 Ma and 1.44 +/- 0.10 Ma, constraining deposition between 1.78 and 0.78 Ma (Calabrian Age) when correlated to the Geomagnetic Polarity Time Scale. Magnetostratigraphy records a reversed-normal-reversed polarity sequence within subchrons C1r.2r, C1r.1n, and C1r.1r. The basin fill dips southward, with thicker accumulations along the southern boundary fault, indicating an asymmetric half-graben geometry dominated by southern-margin subsidence. Syn-depositional growth faults, paleostress analysis, and mesoscopic fault kinematics indicate persistent N-S extension with minor azimuthal variations (NNW-SSE to NE-SW). Paleomagnetic declination data reveal similar to 13 degrees +/- 5 degrees counterclockwise rotation since the Calabrian, supporting differential rotation across the Datca Peninsula and linking basin development to progressive opening of the Gokova Basin. Sedimentological evidence documents initial fluvio-lacustrine conditions, followed by a shallow-marine transgressive phase, with the upper marine deposits now > 100 m above present sea level, implying significant post 0.78 Ma uplift. Uplift and facies associations suggest dynamic topography and slab-edge processes associated with STEP faulting along the Pliny-Strabo Trenches controlled the evolution of the basin. Our results provide the most precise chronological framework to date for the Datca Graben, refine its structural development, and constrain the timing of Gokova Basin opening to post-1 Ma. The integration of magnetostratigraphic, geochronological, and structural datasets sheds light on the understanding of Aegean extensional dynamics and the interplay between regional rotation, uplift, and marine connectivity during the Quaternary.
Paleomagnetic Evidence for Upper Plate Response To a Step Fault, Sw Anatolia
(Elsevier Science Bv, 2018) Kaymakci, Nuretdin; Langereis, Cor; Ozkaptan, Murat; Ozacar, A. Arda; Gulyuz, Erhan; Uzel, Bora; Sozbilir, Hasan
Pliny-Strabo Trench is a Subduction Transform-Edge Propagator (STEP) Fault developed on the northern edge of the subducted African Oceanic Lithosphere. It connects the Aegean and Cyprian trenches in the Eastern Mediterranean convergent system. Although, deep geometry of the STEP fault and associated slab tear in mantle are imaged, its shallow vertical and lateral continuation in the crust and impact on the over-riding plate are still unknown. Thus, we have studied SW Anatolia, the candidate site where this structure could propagate laterally and vertically, for its vertical axis rotations using paleomagnetic tools. In this study, more than 2000 paleomagnetic samples were collected and analysed from 86 different sites which were later classified into 11 separate geographic domains displaying similar tectonic characteristics. Moreover, available paleomagnetic data in the literature were parametrically resampled, analysed and combined with our data. In the region, there is a positive correlation between rotation amounts and sample ages supporting continuous deformation throughout the Neogene period. The spatial variations of results indicated that the study area can be divided into three main domains based on vertical axis rotations. From the south to the north these domains include SW Anatolian domain with similar to 20 degrees counter-clockwise rotation, Burdur-Dinar-Ulubey domain with similar to 4 degrees counter-clockwise rotation and northern areas characterized by clockwise rotations. The identified domains of counter-clockwise rotation are separated by a well-defined NW-SE striking Acipayam Transfer Zone and there is no differential rotation in agreement with the presence of NE-SW striking shear zone in the region. Therefore, we concluded that the Pliny-Strabo STEP Fault have not propagated into the over-riding plate as a shear zone. This implies that there is no evidence to support the presence of alleged Fethiye-Burdur Fault Zone as suggested, and its existence is dubious. (C) 2018 Elsevier B.V. All rights reserved.