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Öğe A hypothesis for the alternative southern branch of the North Anatolian Fault Zone, Northwest Turkey(TMMOB JEOLOJI MUHENDISLERI ODASI, 2016) Seyitoglu, Gurol; Kaypak, Bulent; Aktug, Bahadir; Gurbuz, Esra; Esat, Korhan; Gurbuz, AlperThis paper proposes an alternative route for the southern branch of the North Anatolian Fault Zone (NAFZ) using evidence from morphotectonic features, seismology, GPS and recently published Magnetotelluric and Transient Electromagnetic (MT) data. In this new route, the southern branch connects with the main branch of the NAFZ in Bolu via the Golpazari pull-apart basin and Mudurnu. The slip distribution of the NAFZ as taken from GPS data indicates that the newly hypothesized route is the second most important branch of the NAFZ.Öğe Active tectonics of western Kosovo: Insights from geomorphic and structural analyses(Maden Tetkik Ve Arama Genel Mudurlugu-Mta, 2024) Gurbuz, Alper; Shala, Astrit; Mustafa, Shemsi; Erten, AytekinKosovo is located in a key position in the central-west part of the Balkans, providing an opportunity to understand the far-field effects of distributed intracontinental deformation caused by the Aegean extension in the south and Adriatic compression in the west. It is also situated along the NE-SW trending Shkod & euml;r-Pej & euml; transverse zone, where the Dinarides and Albanides-Hellenides orogenic belts are juxtaposed. While the instrumental seismicity of Kosovo indicates the activity of this fault zone and many others, the active faults in the country were not discussed in detail in the current literature. In this study, we analyzed both the geomorphic and structural features of major mountain front faults in western Kosovo (i.e., Pej & euml;, Istog, Krojmir, and Prizren faults) to reveal the relative assessment of their activities and kinematic characters. Geomorphic and morphometric analyses of all four different mountain fronts studied indicated high activity and tectonic uplift rates of over 0.5 mm/a. On the other hand, according to the collected kinematic data from the observed fault planes, the studied faults are mainly of normal character, representing a dominance of NW-SE-directed extension in western Kosovo, which is most probably caused by the rollback of the subducting slab in the Hellenic trench.Öğe Aeolian control on the deposition of high altitude lacustrine basins in the Middle East: The case of Lake Neor, NW Iran(PERGAMON-ELSEVIER SCIENCE LTD, 2016) Kazanci, Nizamettin; Gulbabazadeh, Tirzad; Leroy, Suzanne A. G.; Ataselim, Zeynep; Gurbuz, AlperLake Neor is the largest lacustrine basin in the high mountains of the Middle East, at 2500 m altitude in the Alborz belt. This lake of Holocene age is a shallow, fresh water body of glacial origin with ca 4 km(2) surface area and a 40 km(2) drainage area. Its sedimentary sequence comprised of peat and gyttja consists of >10 m infill, which is fairly thick for such a lake. Autochthonous organic matter is limited in and around the lake except for small areas at the northern and southern ends. Inorganic constituents of the infill sediment include a significant amount of fine-grained calcite, dolomite and mica particles that are exotic to the catchment. They do not occur in the source rocks, as the drainage area of the lake is composed of only andesites and trachyandesites of Eocene age. In addition, the uppermost part of the infill includes abundant fine-grained charcoal particles derived from large forest fires perhaps derived as far as the Mediterranean region. As shown by the present meteorological records, the sediment of Lake Neor is under aeolian control during dust storms; this is leading to a considerable amount of deposition air-borne particles. The infill of some lakes, particularly those in highlands, may have contain an important aeolian component and thus they cannot be used directly for the interpretation of the evolution of the palaeogeography without taking into consideration the role of dust storms on deposition. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.Öğe Complex basin evolution in the Gokova Gulf region: implications on the Late Cenozoic tectonics of southwest Turkey(SPRINGER, 2013) Gurer, Omer Feyzi; Sangu, Ercan; Ozburan, Muzaffer; Gurbuz, Alper; Sarica-Filoreau, NuranSouthwestern 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.Öğe Genetic framework of Neogene-Quaternary basin closure process in central Turkey(GEOLOGICAL SOC AMER, INC, 2015) Gurbuz, Alper; Kazanc, NizamettinCentral Turkey represents the only orogenic plateau in the Mediterranean region. Also, the largest closed drainage basin and the largest intracontinental basin of Turkey, the Lake Tuz Basin, is located in this region. Results from a three-dimensional (3-D) computer modeling study of the Lake Tuz Basin indicate a southward-deepening freshwater lake basin with great depth in the Mio-Pliocene, which regressed toward the north during the Plio-Quaternary into the shallow saline lake basin it is today. The spatio-temporal variations of Neogene and Quaternary deposits reflect the main effects of internal forces (isostasy>volcanism>faulting) that were caused by lithospheric slab breakoff and subsequent asthenospheric upwelling under central Turkey. Climatic change played a relatively minor role during these periods and was closely associated with the results of internal forces.Öğe Geological evolution of a tectonic and climatic transition zone: the Beysehir-Sugla basin, lake district of Turkey(Springer, 2021) Gurbuz, Alper; Kazanci, Nizamettin; Hakyemez, H. Yavuz; Leroy, Suzanne A. G.; Roberts, Neil; Sarac, Gercek; Ergun, ZeynepCentral-west Turkey is a transition zone both tectonically and climatically between the quite different central and western regions of Anatolia. Central Anatolia represents the seismically quiet part of the otherwise highly active Turkey. On the other hand, this region has some of the lowest precipitation and highest evaporation ratios of Turkey. Conversely, west Anatolia is one of the most rapidly extending regions of the world and seismically very active. The climate is very different from the central part of Turkey and more humid. The zone between these two regions is also known geologically as the Isparta Angle. This reverse-V-shaped fold and thrust belt has several lake basins today, which have archived the geological and geomorphological history of this tectonic and climatic transition zone. The Beysehir-Sugla basin is located on the eastern part of this zone. This NW-SE trending basin includes the largest natural freshwater lake of the Mediterranean region: Lake Beysehir. Lakes Beysehir and Sugla are located in this tectonic depression that discharge into an incised river gorge opening to the Konya closed basin. In order to shed light on the development of the Beysehir-Sugla basin, our study was mainly conducted within the Neogene and Quaternary units of the region. Our structural results indicate that the depression was probably formed by a transtensional regime in the middle Miocene, which is controlled by extensional tectonics since the early Quaternary. Also, the current depression has mainly embodied the structures that are the products of these tectonic phases. According to our sedimentary data and palaeoecological interpretation of available palaeontological data, the Beysehir-Sugla basin was developed initially under a humid and warm climate in the middle Miocene; then since the late Miocene-Pliocene it was controlled by a relatively more arid and, at times, humid climate more like the central Anatolian basins. Although the Beysehir-Sugla basin is hydrologically connected to the Konya closed basin in central Anatolia, it was protected from arid climatic conditions for over millions of years as evidenced by the lack of evaporites in the studied basin and surrounding basins located in the interior part of the Isparta Angle. While the regional climate seems to have changed consistently with the geomorphic response to large-scale tectonics (i.e. orographic barrier development), the Beysehir-Sugla basin seems to be protected from hydrological closure by the existence of karstic features in the surrounding carbonate basement rocks.Öğe Geomorphometric imprints of flank collapses on volcanic edifices: Implications from the case of Mount St. Helens(Springer, 2022) Gurbuz, AlperAnalyzing the geomorphometric traces of volcanic eruptions by comparing pre- and post-eruption maps and images of volcanic edifices can quantitatively indicate drastic changes in topography enlightening the effects of volcanic flank collapses. Volcanic edifices are inherently prone to experience flank collapses and related large landslides at some point of their evolution, which significantly change the volcanic landscape and totally destroy everything in their paths. If the flank collapses occurred on volcanic edifices in islands, they are also adequate to cause tsunamis with larger devastating effects. Thus, recognizing the imprints of flank collapses and their effects on volcanic edifices has critical importance. Comparison of pre- and post-eruption elevation, slope, aspect, and hypsometry analyses of the regular cone-shaped pre-eruption volcanic edifice as in the case of May 18, 1980 eruption of Mount St. Helens in Washington provides an excellent opportunity to understand the influence of such a rapid catastrophic event on landscape evolution. The volcanic flank collapse during the eruption particularly affected the upper 1500 m. The collapsed part increased the percentage of region between 1500 and 2150 m, particularly accumulated around similar to 1950 m, and created a plateau morphology because of landsliding and debris avalanche. The maximum and average maximum slope values of the edifice significantly increased in the upper part of this altitude due to flank collapse-related scar development. Post-eruption redistributions of slope values and aspect directions have also changed obviously, and represent the signatures of an amphitheater (horseshoe/C-) shaped scarp and plateau morphology developments particularly for the highest (40 degrees <) and lowest (0-10 degrees) slope ranges, respectively. On the other hand, the comparison of pre- and post-eruption hypsometries of the volcanic edifice represents an increase against the decreased relief of the volcanic edifice as a result of the flank collapse and landsliding, which created a large plateau on the northern sector, affected the elevation-area relation of the volcanic edifice in a different way. The results represent how such a destructive event can be a rejuvenating process on the topography as in the case of Mount St. Helens by increasing slope and hypsometry.Öğe Is there activity switching among the continental transform faults in the Eastern Mediterranean region?(Springer, 2023) Gurbuz, AlperThe historical and instrumental seismicity records along the continental transform faults in the Eastern Mediterranean region represent periodicities within centennial scales. Half a century ago, it was suggested that the spatiotemporal sequences of millennial-scale historical seismicity along the interplate structures represent seismicity switching between the North Anatolian Fault Zone and the East Anatolian Fault Zone. However, many individual historical seismicity catalogs published in the last decade indicate a comparable number of earthquakes in the North Anatolian and Dead Sea fault zones, but not in the East Anatolian Fault Zone. Seismicity records of the instrumental period indicate that the North Anatolian Fault Zone is currently at its peak level of activity. On the other hand, it is well known from the historical records that the seismically quiescent instrumental period of the Dead Sea Fault Zone is not representative of its potential. The comparison of various individual historical earthquake catalogs implies a successive activity for the North Anatolian and Dead Sea fault zones, with a discernible time delay. This observation lends supports to elastic coupling between these continental transform faults, resulting from the direct interaction between the movements of the Arabian and Anatolian plates. The evaluation of both historical and instrumental periods together reveals a possibility to speculate that the Dead Sea Fault Zone could enter a more active phase in the near future, potentially exhibiting a time lag in relation to the activity observed in the North Anatolian Fault Zone.Öğe Plio-Quaternary kinematic development and paleostress pattern of the Edremit Basin, western Turkey(ELSEVIER SCIENCE BV, 2016) Gurer, Omer Feyzi; Sangu, Ercan; Ozburan, Muzaffer; Gurbuz, Alper; Gurer, Aysan; Sinir, HasanThe 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.Öğe Remote sensing approaches for mapping Quaternary deposits: A synthesis(Pergamon-Elsevier Science Ltd, 2022) Gurbuz, Alper; Gurbuz, EsraThe importance of producing palaeoenvironmental, palaeoclimatic and palaeoseismological data for archaeological, environmental, climate change and active tectonic studies enhances the importance of mapping Quaternary deposits. Urbanisation mainly develops on plains that are geographically attractive and generally covered by Quaternary deposits. The basic reasons for this are related to their suitability for transportation and intersection with water resources. Beyond their characterisation as only 'alluvium' in almost all geological maps, detailed information about Quaternary plains is now essential for engineering purposes, particularly because of earthquakes and related liquefaction problems. In this study, remote sensing approaches for mapping Quaternary deposits are reviewed. Although the success of using airphotos, multispectral and hyperspectral (passive systems), and radar and LiDAR (active systems) images in mapping of Quaternary units is remarkable, their uses are generally individual, and thus they are far from presenting comprehensive results. We expect that the using remote sensing approach for mapping of Quaternary deposits, systematically based on mapping of lithological, geomorphological and soil characteristics together, which are mainly considered in the geological mapping of areas covered by Quaternary deposits individually, offers the most reliable approach. While the passive system sensors are particularly important for mapping lithological and soil features, the active system sensors are more convenient for geomorphological and soil mapping. Field mapping still remains essential; however, there is an increasing need for rapid mapping of Quaternary units before they are covered by anthropogenic interventions (e.g. afforestation, urbanisation, agricultural use). The combined use of different parameters outlined in this study can facilitate and accelerate more reliable mapping of Quaternary deposits according to their depositional environments.Öğe Right-Lateral Strike-Slip Faulting and Related Basin Formations in the Turkish-Iranian Plateau(Elsevier Science Bv, 2018) Gurbuz, Alper; Saroglu, Fuat[Abstract Not Available]Öğe Strike-slip faulting, topographic growth and block movements as deduced from drainage anomalies: The Yesilirmak River basin, northern Turkey(ELSEVIER SCIENCE BV, 2015) Gurbuz, Esra; Kazanci, Nizamettin; Gurbuz, AlperThis study aims to understand the various effects of known tectonism on a fluvial network and to interpret the tectonic deformations using described, and analysed systematic anomalies in the drainage basin of the Yesilirmak River in northern Turkey at countermarch. This region, which is divided into several faulted wedges by right-lateral strike-slip faulting of the North Anatolian fault zone and its individual splays, has experienced several moderate to large earthquakes with high amounts of surface ruptures during the historical and instrumental periods. The Yesilirmak River basin includes several geomorphic imprints of such widespread and frequent strike-slip deformations. Offsets (between 750 m and 19 km), aligned drainages, and linear valleys (170 km) are expected geomorphic and tectonic responses to strike-slip faulting in the fluvial system. We used such indicators to determine the long term effects of strike-slip faulting in the Yesilirmak River drainage network. The measured stream offsets represent decreasing values toward southern splay faults consistent with published geodetic data for the region. However, some other large-scale geomorphic anomalies extracted from the drainage network are not explainable by only strike-slip tectonics. Compressional structures, i.e., anticlines, synclines, in the region are responsible for such large-scale drainage diversions (20-24 km) along the river courses. Although these diversions, the North Anatolian fault zone is the main driving force shaping present geomorphology on a regional scale. The Sungurlu-Ezinepazari fault also plays a critical role in landscape evolution. Their activities and associated block movements have resulted with tilting processes. On the other hand, the entire fluvial network should be modified by the sea level changes of the Black Sea, particularly in the late Quaternary. (C) 2015 Elsevier B.V. All rights reserved.Öğe Tectonic Geomorphology of the Zagros Orogen(Elsevier Science Bv, 2018) Gurbuz, Alper; Saein, Ali Farzipour[Abstract Not Available]Öğe The discovery of a low-angle normal fault in the Taurus Mountains: the Ivriz detachment and implications concerning the Cenozoic geology of southern Turkey(Tubitak Scientific & Technological Research Council Turkey, 2017) Seyitoglu, Gurol; Isik, Veysel; Gurbuz, Esra; Gurbuz, AlperThe Ivriz detachment fault has been determined on the southern border of the Ulukisla basin separating the metamorphic Bolkar Group of the Taurus Mountains and the Paleocene-Lower Eocene Halkapinar formation of basin deposits. The fault dips towards the north and has kinematic indicators (asymmetric grain/grain aggregate porphyroclasts, oblique foliation, and S-C fabrics), suggesting a top-to-the-N-NE sense of shearing. The clastic material originating from the Bolkar Group in the sedimentary units of the Ulukisla basin demonstrates that the detachment fault could have been be active during Latest Cretaceous-Eocene times. The Ivriz detachment may have initiated as part of a high-angle breakaway fault (the Aydos main breakaway fault) in the south of the Ulukisla basin. The breakaway fault then rotated to a low-angle normal fault and its northern continuation played an important role in the exhumation of the Central Anatolian Crystalline Complex. This implies that the Upper Cretaceous-Eocene sedimentary basins in central Anatolia were supradetachment basins rather than collision- or arc-related basins as previously suggested.
