Browsing by Author "Langereis, Cor G."

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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.
Rotations of Normal Fault Blocks Quantify Extension in the Central Tauride Intramontane Basins, Sw Turkey
(Amer Geophysical Union, 2018) Koc, Ayten; van Hinsbergen, Douwe J. J.; Langereis, Cor G.
Quantifying the amount of stretching in extensional basin systems is often challenging in the absence of seismic profiles or boreholes. However, when fault spacing and orientation as well as vertical axis rotation patterns are known, map-view restoration may provide a good estimate of total extension. This integrated structural and paleomagnetic approach provides a relatively straightforward tool in extensional basin restoration and fault zone kinematic analysis. Here we provide results of an extensive paleomagnetic survey of the Neogene Central Tauride intramontane basins (SW Turkey), where previous work revealed a complex array of basin-bounding normal faults and relay ramps. In total, 437 oriented cores were sampled at 43 sites distributed within Miocene-Pliocene continental sedimentary rocks from the Ilgn, Altnapa, Yalvac, and Beyehir basins. Despite the more or less coherent overall strike of the mountain belt and basins, rotations vary from 42 degrees clockwise (Yalvac) to 10 degrees (Beyehir), 21 degrees (Ilgn), and 30 degrees (Altnapa) counterclockwise. We show that the rotation pattern is related to normal faults and lateral variations in fault displacement superimposed on regional rotation patterns. We restore these to estimate a minimum NE-SW horizontal extension of 30-35km across the basin system. As a consequence of our reconstruction, it appears that the Sultandalar range that exposes low-grade metamorphic Paleozoic and Mesozoic rocks of the Geyikda and Bolkarda nappes of the Taurides represents a Miocene extensional core complex. Key Points