Stratigraphic comparisons along the Pontides (Turkey) based on new nannoplankton age determinations in the Eastern Pontides: geodynamic implications

We compared the stratigraphic formations along the southern margin of the Black Sea using 196 nannoplankton ages determined in the Western and Central Pontides and 112 new samples from the Eastern Pontides. We inferred that the I. stanbul and Sakarya zones were amalgamated prior to the Early Cretaceous. Extensional subsidence migrated eastwards along the Pontides from the Barremian to the Paleocene. The eastwards younging of the Cretaceous magmatism suggested that the eastern Black Sea Basin is younger. Locally, angular unconformities and a stratigraphic gap testify to the Late Albian uplift of the Central Pontides as a consequence of the collision of an oceanic edifice. Cretaceous Oceanic Red Beds are marker beds of Santonian age along the much of the Pontides and are of mainly Campanian age within the Eastern Pontides. The Middle Campanian-Paleocene was a non-volcanic period characterized by extensional subsidence mainly along the eastern Black Sea Basin. The end of Cretaceous volcanism can be correlated with a southwards subduction jump. Syn-compressional basins show that contraction started during the Ypresian along the entire Pontide belt. Eocene volcanism started earlier in the north (Lutetian) than in the south (Bartonian) of the Eastern Pontides. This propagation of syn-collisional volcanism could have resulted from slab steepening under the Eastern Pontides

Complex basin evolution in the Gokova Gulf region: implications on the Late Cenozoic tectonics of southwest Turkey

WOS: 000325804900007Southwestern Turkey experienced a transition from crustal shortening to extension during Late Cenozoic, and evidence of this was recorded in four distinct basin types in the Mugla-Gokova Gulf region. During the Oligocene-Early Miocene, the upper slices of the southerly moving Lycian Nappes turned into north-dipping normal faults due to the acceleration of gravity. The Kale-Tavas Basin developed as a piggyback basin along the fault plane on hanging wall blocks of these normal faults. During Middle Miocene, a shift had occurred from local extension to N-S compression/transpression, during which sediments in the Eskihisar-TA +/- naz Basins were deposited in pull-apart regions of the Menderes Massif cover units, where nappe slices were already eroded. During the Late Miocene-Pliocene, a hiatus occurred from previous compressional/transpressional tectonism along intermountain basins and Yatagan Basin fills were deposited on Menderes Massif, Lycian Nappes, and on top of Oligo-Miocene sediments. Plio-Quaternary marked the activation of N-S extension and the development of the E-W-trending Mugla-Gokova Grabens, co-genetic equivalents of which are common throughout western Anatolia. Thus, the tectonic evolution of the western Anotolia during late Cenozoic was shifting from compressional to extensional with a relaxation period, suggesting a non-uniform evolution.Scientific and Technical Research Council of Turkey (TUBITAK) [CAYDAG-108Y277]The study is supported by The Scientific and Technical Research Council of Turkey (TUBITAK) (CAYDAG-108Y277). The authors are thankful to Dr. Efem ALTINOK and Dr. Aziz OZYAVAS for critical reading of the manuscript. The authors gratefully acknowledge the assistance of Mr. H. Tanzer AYDEMIR of the South Aegean Lignite Establishment (GELI.). Reviews of the manuscript by Dr. Ali Elmas and an anonymous reviewer are greatly appreciated. We thank Dr. Wolf-Christian Dullo for his constructive review and editorial comments

Plio-Quaternary kinematic development and paleostress pattern of the Edremit Basin, western Turkey

WOS: 000378177700015The Edremit Basin and Kazdag High are the most prominent morphological features of the Biga Peninsula in northwest Anatolia. There is still no consensus on the formation of Edremit Basin and debates are on whether the basin evolved through a normal, a right-lateral or a left-lateral strike-slip faulting. In this study, the geometric, structural and kinematic characteristics of the Edremit Basin are investigated to make an analytical approach to this problem. The structural and kinematic features of the faults in the region are described according to field observations. These fault-slip data derived from the fault planes were analyzed to determine the paleostress pattern of faulting in the region. According to the performed analysis, the southern end of the Biga Peninsula is under the influence of the ENE-WSW-trending faults of the region, such as the Yenice-Gonen, the Edremit, the Pazarkoy and the Havran-Balikesir Fault Zones. The right step-over geometry and related extension caused to the development of the Edremit Basin as a transtensional pull-apart basin between the Havran-Balikesir Fault Zone and the Edremit Fault Zone. Field observations showed that the Plio-Quaternary faults at the Edremit Gulf and adjacent areas are prominently right-lateral strike-slip faults. Our paleostress analyses suggest a dominant NE-SW extension in the study area, as well as NW-SE direction. This pattern indicates the major effects of the North Anatolian Fault System and the component of Aegean Extensional System in the region. However, our kinematic analysis represents the dominant signature of the North Anatolian Fault System in basin bounding faults. The field observations and kinematic findings of this study are also consistent with the regional GPS, paleomagnetic and seismological data. This study concludes that the North Anatolian Fault System is the prominent structure in the current morphotectonic framework of the Edremit Gulf and adjacent areas. (C) 2016 Elsevier B.V. All rights reserved.Scientific and Technical Research Council of Turkey (TUBITAK) [CAYDAG-111Y258]The study is supported by The Scientific and Technical Research Council of Turkey (TUBITAK) with grant no: CAYDAG-111Y258. The authors are grateful to Bahadir Aktug (AU) for interpretations on the GPS derived data of the region. Constructive comments made by Uwe Ring and two anonymous reviewers greatly improved the manuscript

Geodynamic evolution of the Black Sea Basin: Constraints from structural data and fault kinematic analyses along the Black Sea coasts (Pontides and Crimean Mountains).

International audienceThe geodynamic evolution of the Black Sea Basin can be unravelled by structural and kinematic analyses along its inverted margins. In the frame of the Darius Programme we acquired structural data in the Pontides and in the Crimean Mountains. In the Western Pontides intense extensional faulting occurred during the Early Cretaceous and controlled the deposition of the siliciclastic sediments dated as Hauterivian to Albian (Hippolyte et al., 2010). Development of horst and graben structures resulted in the gravitational sliding of limestone olistoliths. The early Cretaceous fault blocks are unconformably overlain by a Late Cretaceous sequence that generally begins with Coniacian red pelagic limestones.Similar to the Western Pontides, in the Central Pontides intense extensional deformation took place during the Early Cretaceous when sedimentation was characterized by olistoliths and debris flows. Tectonic subsidence locally reached 3600 m. During the Cenozoic, inversion of normal faults created a doubly vergent orogenic wedge (Espurt et al., 2014).On the conjugate margin of the Black Sea, we mapped an array of collinear normal faults in the western part of the Crimean Mountains (Hippolyte et al, 2018). These faults trend parallel to the crustal-scale structures of the Black Sea Basin. Similar to the Pontides, extensional block faulting occurred during the deposition of debris flow and olistoliths, and the extension direction was NE-SW. The syn-rift sequence is dated as Valanginian-Late Albian. The post-rift sequence, that unconformably overlies the graben structures, starts in the Cenomanian. It is devoid of any normal faults or olistoliths. In the eastern Pontides we studied the onshore extension of the transfer faults of the eastern Black Sea Basin. From the Early Campanian to the Late Paleocene they only move with normal slip, possibly related to thermal subsidence in the Black Sea Basin (Hippolyte et al., 2017). Therefore, their strike-slip displacement, related to the opening of the Eastern Black Sea Basin, must predate the Campanian.Given the fact that extensional structures are presents on the two conjugate margins of the Black Sea, and that the directions of extension are normal to the crustal structures (mid-Black Sea High and Black Sea margins), we infer that the Early Cretaceous extension is related to the rifting phase of the Black Sea Basin. We conclude that rifting occurred from the Valanginian to the Late Albian. The age of the breakup unconformity in Crimea, and the Late Cretaceous evolution of the transfer faults, suggest a drifting period from the Cenomanian to the Santonian, a period of intense volcanic activity and weak extensional deformation along the southern margin of the Black Sea. Based on the directions of rifting we propose that the Black Sea Basin opened with rotations accommodated by transform faults at its western and eastern margins, as a consequence of two asymmetric rollbacks of the northward subducted Neo-Tethyan slab. The inversion of the Black Sea margins results from several shortening events related to the continental collisions that occurred to the south. We characterize these events by distinct compressional stress fields from the Eocene to the Quaternary

Geodynamic evolution of the Black Sea Basin: Constraints from structural data and fault kinematic analyses along the Black sea coasts (Pontides and Crimean Mountains)

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