Browsing by Author "Langereis, Cornelis G."

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Late Neogene Oroclinal Bending in the Central Taurides: a Record of Terminal Eastward Subduction in Southern Turkey
(Elsevier Science Bv, 2016) Koc, Ayten; van Hinsbergen, Douwe J. J.; Kaymakci, Nuretdin; Langereis, Cornelis G.
The Tauride fold-thrusts belt formed during similar to S-N convergence between Africa and Eurasia since Cretaceous time. The western end of the central Taurides strike NW-SE, highly obliquely to the overall convergence direction, and connect to the NE-SW Beydaglan-Lycian Nappe flank of the western Taurides, forming the so-called 'Isparta Angle'. In Neogene time, the western and central Taurides and the inner part of the Isparta Angle became overlain by Neogene sedimentary basins including Manavgat, Koprucay and Aksu, characterized by marine clastics and carbonates. The eastern limb of the Isparta Angle experienced multidirectional Miocene to Present extension, whereas E-W shortening affected the marine sedimentary basins in the heart of the Isparta Angle. To quantitatively reconstruct the Neogene kinematic evolution of the Taurides, towards restoring the subduction system accommodating Africa-Eurasia convergence, we paleomagnetically assess if and when vertical axis rotations affected the Manavgat, Koprucay, and Aksu basins in Early Miocene to Pliocene times. We show that the northern Koprucay Basin rotated similar to 20-30 degrees clockwise, the Manavgat Basin underwent similar to 25-35 degrees counterclockwise rotation, and the Aksu Basin underwent no rotation since the Early-Middle Miocene. It was previously shown that the Beydaglari region underwent a post-Middle Miocene similar to 20 degrees counterclockwise rotation. These results show that the prominent oroclinal salient geometry of the western Taurides thus acquired, at least in part, since Miocene times, that the Koprucay Basin rotated relative to the Aksu Basin along the Aksu thrust, and that the Beydaglari platform rotated relative to the Aksu Basin along the Bucak thrust, which must have both been active until Late Neogene time. This synchronous E-W shortening in the heart of the Isparta Angle, and multidirectional extension in its eastern limb may be explained by relative westward retreat of an eastward dipping subducting Antalya slab that has previously been imaged by seismic tomography and a Benioff zone. The Neogene Bucak thrust west of the Aksu Basin may represent the most recent surface expression of the Antalya subduction zone. (C) 2015 Elsevier B.V. All rights reserved.
Neogene Kinematics of the Potwar Plateau and the Salt Range, Nw Himalayan Front: a Paleostress Inversion and Ams Study
(Taylor & Francis inc, 2022) Qayyum, Abdul; Poesse, Jorik Willem; Kaymakci, Nuretdin; Langereis, Cornelis G.; Gulyuz, Erhan; Ahsan, Naveed
We provide new kinematic data from the Potwar Plateau (Pakistan) to evaluate the tectonic evolution of the region during the Neogene. The plateau is bound by two major strike-slip faults in the west and the east, accommodating its southwards translation. We have recognized two Neogene deformation phases in the plateau, based on paleostress inversion and Anisotropy of Magnetic Susceptibility (AMS) tensors. The first phase lasted until the early Pliocene and was characterized by vertical minor stress and N-S compression, implying thrust tectonics. The second deformation phase is characterized by a near-vertical intermediate principal stress and near-horizontal major and minor stresses, interpreted to be associated with strike-slip tectonics since the late Pliocene. K-int vectors from 21 sites are relatively compatible with the major principal stress orientations (sigma(1)) and indicate two distinct domains. This is possibly because K-min orientations are related to compaction, whereas K-int orientations were always parallel to tectonic shortening and hence compression direction during both strike-slip (post-late Pliocene) and thrusting (pre-late Pliocene) phases. These phases are characterized by swapping of (sigma(2)) and (sigma(3)) orientations while (sigma(1)) maintained its orientation. The most prominent change occurs at the western part of the Potwar Plateau, where major principal stress directions (sigma(1)) and K-int axes fan out south-westwards. The eastern domain is dominated by NE-SW trending folds and thrust faults, which are absent in the western domain. These structural features are interpreted to be the result of the distribution of deposits of the Neoproterozoic Salt Range Formation as a substratum below the Potwar Plateau. The Salt Range Formation is very thick and widespread in the west area and almost absent in the east. This factor led to unconstrained southwards gliding of the Potwar Plateau over the salt deposits in the west as opposed to frictional sliding and substantial internal deformation in the east.