Episodic, two-stage Neogene extension and short-term intervening compression in Western Turkey: field evidence from the Kiraz Basin and Bozdag Horst

Western Anatolia (Turkey) is a region of widespread active N-S continental extension that forms the eastern part of the Aegean extensional province. The extension in the region is expressed by two distinct/different structural styles, separated by a short-term gap: (1) rapid exhumation of metamorphic core complexes along presently low-angle ductile-brittle normal faults commenced by the latest Oligocene-Early Miocene period, and; (2) late stretching of crust and, consequent graben evolution along Plio-Quatemary high-angle normal faults, cross-cutting the pre-existing low-angle normal faults. However, current understanding of the processes (tectonic quiescence vs N-S continental compression) operating during the short-time interval is incomplete. This paper therefore reports the results of recent field mapping and structural analysis from the NE of Kucuk Menderes Graben-Kiraz Basin-that shed lights on the processes operating during this short-time interval. The data includes the thrusting of metamorphic rocks of the Menderes Massif over the Mio-Pliocene sediments along WNW-ESE-trending high-angle reverse fault and the development of compressional fabrics in the metamorphic rocks of the Menderes Massif. There, the metamorphic rocks display evidence for four distinct phases of deformation: (1) south-facing top-N ductile fabrics developed at relatively high-grade metamorphic conditions, possibly during the Eocene main Menderes metamorphism (amphibolite facies) associated with top-N thrust tectonics (D-1); (2) top-S and top-N ductile gentle-moderatley south-dipping\ extensional fabrics formed at relatively lower-grade metamorphic (possibly greenschist facies) conditions associated with the exhumation of Menderes Massif along presently low-angle normal fault plane that accompanied the first phase of extension (D,); (3) moderately north-dipping top-S ductile-brittle fabrics, present configuration of which suggest a thrust-related compression (D-3); and (4) south-facing approximately E-W-trending brittle high-angle normal faults (D-4) that form the youngest structures in the region. It is interpreted that D-4 faults are time equivalent of graben-bounding major high-angle normal faults and they correspond to the second phase of extension in western Anatolia. The presence of thrust-related D3 compressional fabrics suggests N-S compression during the time interval between the two phases of extension (D-2 and D-4). The results of the present study therefore support the episodic, two-stage extension model in western Anatolia and confirm that a short-time, intervening N-S compression separated the two distinct phases. (c) 2005 Lavoisier SAS. All rights reserved.


Late Alpine evolution of the central Menderes Massif, western Turkey
Bozkurt, Erdin (2001-04-01)
The central Menderes Massif (western Turkey) is characterized by an overall dome-shaped Alpine foliation pattern and a N-NNE-trending stretching lineation. A section through the southern flank of the central submassif along the northern margin of Buyuk Menderes graben has been studied. There, asymmetric non-coaxial fabrics indicate that the submassif has experienced two distinct phases of Alpine deformation: a top-to-the N-NNE contractional phase and a top-to-the S-SSW extensional event. The former fabrics ...
Tectonic evolution of the Cretaceous Ankara Ophiolitic Melange during the Late Cretaceous to pre-Miocene interval in Central Anatolia, Turkey
Rojay, Fuat Bora (2013-04-01)
The chaotic tectonic belt, which is distinguished in northern Anatolia, is called the - Ankara Accretionary Complex - in the Ankara region, central Anatolia. The belt is differentiated into three imbricated tectonic subbelts, namely, pre-Triassic metamorphics, Melange with calcareous blocks and Cretaceous melange with ophiolitic blocks (Ankara Ophiolitic Melange).
Spatial variations of active stress patterns and frequencymagnitude distribution of earthquakes in Western Anatolia, Turkey
Shah, S Tanvir; Özacar, Atilla Arda (null; 2018-04-23)
Western Anatolia is one of the most important tectonic elements of Turkey, and constitutes the eastern margin of Aegean Extensional Province. The area is one of the most seismically active continental margins around the globe experiencing N-S extension. Earthquake data in this study is used to analyze the active stress patterns and to estimate the earthquake return periods for different sub-regions in western Anatolia. Focal mechanism solution data is used for determining the orientations and ratios of prin...
Upper Cretaceous Radiolarian ages from an arc-back-arc within the Yuksekova Complex in the southern Neotethys melange, SE Turkey
TEKİN, UĞUR KAĞAN; Ural, Melek; Göncüoğlu, Mehmet Cemal; ARSLAN, MEHMET; KÜRÜM, SEVCAN (2015-02-01)
The Yuksekova complex in SE Turkey is a part of a continuous belt of ophiolites and subduction-accretion complexes that stretches from Troodos in the west to Oman in the east, representing the remnants of the Southern Branch of Neotethys. This complex mainly comprises a tectonically chaotic assemblage of basaltic dykes and pillow lavas associated with radiolarian cherts, shales and pelagic limestones. Detailed petrological work on submarine basaltic lavas from Elazig-Malatya area in SE Turkey revealed the p...
Tectonic evolution of the Gediz Graben: field evidence for an episodic, two-stage extension in western Turkey
Bozkurt, Erdin (Cambridge University Press (CUP), 2004-01-01)
Western Turkey is one of the most spectacular regions of widespread active continental extension in the world. The most prominent structures of this region are E-W-trending grabens (e.g. Gediz and Buyuk Menderes grabens) and intervening horsts, exposing the Menderes Massif. This paper documents the result of a recent field campaign (field geological mapping and structural analysis) along the southern margin of the modern Gediz Graben of Pliocene (similar to 5 Ma) age. This work provides field evidence that ...
Citation Formats
E. Bozkurt, “Episodic, two-stage Neogene extension and short-term intervening compression in Western Turkey: field evidence from the Kiraz Basin and Bozdag Horst,” GEODINAMICA ACTA, pp. 299–316, 2005, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/37654.