Middle Pleistocene tectonic events around the SE Aegean Sea - Insights from magnetostratigraphy - zircon (U-Th)/He dating - and fault kinematics

Sep 30, 2026

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Study constrains the stratigraphy, age, and tectono-sedimentary evolution of the Datça Graben (SW Türkiye) using integrated magnetostratigraphy, zircon (U–Th)/He geochronology, sedimentology, and fault-kinematic analysis. N–S extension along the Anatolian margin formed an asymmetric half-graben with growth faults and southward-dipping basin fill. Zircon ages of 1.56 ± 0.10 Ma and 1.44 ± 0.10 Ma bracket deposition between 1.78 and 0.78 Ma. Paleomagnetism indicates ~13° ± 5° counterclockwise rotation and links development to post-1 Ma opening of the Gökova Basin, with later uplift exceeding 100 m above present sea level.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages18

Reading Time45 min

AccessFree to download

Datça Graben: scope and integrated methods

Stratigraphy, basin evolution, and deposition timing

Magnetostratigraphy and polarity sequence

Geochronology from zircon (U-Th)/He

Fault kinematics, paleostress, and half-graben geometry

Paleomagnetic rotation and Gökova Basin linkage

Sedimentological evolution and uplift implications

Regional tectonic context for Aegean extension

[www. nature.com/scientificreports](www. nature.com/scientificreports) OPEN Middle Pleistocene tectonic events around the SE Aegean Sea: Insights from magnetostratigraphy,(U– Th)/He zircon dating, and fault kinematics in the DatçaGraben (SW Türkiye) Meryem Dilan İnce1, Nuretdin Kaymakci1,2􀀍, Cor Langereis3, Bora Uzel4, Erhan Gülyüz2,5, ErsinO. Koralay4, Marius Stoica6 & Ökmen Sümer4 This study constrains the stratigraphy, age, and tectono-sedimentary evolution of the Datça 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 ~ 350 m offluvio-lacustrine to shallow-marine deposits, primarily assigned to theYıldırımlı Formation. Two interbedded tuff layers yield zircon (UTh)/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. Syndepositional 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 ~ 13° ± 5° counterclockwise rotation since the Calabrian, supporting differential rotation across the Datça Peninsula and linking basin development to progressive opening of the Gökova Basin. Sedimentological evidence documents initial fluvio-lacustrine conditions, followed by a shallowmarine 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 Datça Graben, refine its structural development, and constrain the timing of Gökova 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. Keywords Datça Graben, Extensional tectonics, Magnetostratigraphy, Thermochronological dating, Kinematic analysis, Gökova Basin 1Department of Geological Engineering, Middle East Technical University (METU), Dumlupınar Bulvarı 1, 06800 Ankara, Turkey. 2Department of Neotectonics and Thermochronology, Institute of Rock Structure and Mechanics of the Czech Academy of Science, V Holesovickach 94/41, 182 09 Prague 8, Czech Republic. 3Department of Earth Sciences, Utrecht University, Budapestlaan 17, 3584 CD Utrecht, the Netherlands. 4Department of Geological Engineering, Dokuz Eylül University, Tınaztepe Campus, 35160 İzmir, Turkey. 5Department of Geological Engineering, VanYüzüncüyıl University, TR-65080 Van, Turkey. 6Geology and Geophysics, University of Bucharest, 050107 Bucharest, Romania. 􀀍 email: [kaymakci@metu.edu.tr](kaymakci@metu.edu.tr) [www. nature.com/scientificreports/](www. nature.com/scientificreports/) The Aegean and southwestern Anatolia region is key to understanding extensional deformation related to slabedge processes, including subduction roll-back and STEP faulting. These processes govern deformation in the overlying plate, leading to crustal stretching, thinning, and dynamic topography, which, in turn, gave way to sea-level fluctuations, basin formation, and sediment deposition. Since the late Oligocene, the Aegean region has experienced vertica

FAQs

How does magnetostratigraphy constrain the timing of deposition in the Datça Graben?

Magnetostratigraphy records a reversed–normal–reversed polarity sequence within subchrons C1r.2r, C1r.1n, and C1r.1r, providing chronological control when correlated to the Geomagnetic Polarity Time Scale.

What zircon (U-Th)/He ages were obtained, and what deposition interval do they bracket?

Two 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).

What tectonic model best explains the basin geometry and fault activity described in the study?

The basin fill dips southward with thicker accumulation along the southern boundary fault, indicating an asymmetric half-graben dominated by southern-margin subsidence, sustained by N–S extension with minor azimuthal variations.

Sep 30, 2026

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