Browsing by Author "Langereis, Cor"

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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.