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Öğe A review of the geothermal system evolution and distribution in the Central Anatolian Crystalline Complex (Turkiye)(Tubitak Scientific & Technological Research Council Turkey, 2023) Sener, Mehmet Furkan; Ozturk, Muhammed Zeynel; Baba, AlperTurkiye is located in the Mediterranean sector of the Alpine-Himalayan tectonic belt and is among the foremost seven countries in the world having an abundance of geothermal resources. The Central Anatolian Crystalline Complex (CACC) is one of the most important geothermal regions in Turkiye. This study aims to evaluate the geothermal system of CACC using the geological, structural, and hydrogeochemical properties that were obtained from previous studies. The present study investigated and evaluated the hydrogeochemical and isotopic properties of 762 water samples belonging to 45 different localities from 41 scientific studies. The result shows that CACC has different heat sources and different hydrogeochemical processes. Major element chemistry of the water reveals that the geothermal fluids are mostly of the Ca -Mg -HCO3 , Na -Cl -HCO3 , and Ca-Cl water types. Silica geothermometers suggest that the reservoir temperature ranges from 48 to 180 degrees C. Based on the delta 18O -delta D relationship, water samples have a high-altitude meteoric origin. Stable isotopic data indicate that the geothermal fluids are formed by local recharge and deep circulation of meteoric waters.Öğe Aeolian imprints of multiple Mediterranean invasions of the Black Sea during Pleistocene(Elsevier, 2022) Erginal, Ahmet Evren; Kiyak, Nafiye Gunec; Makaroglu, Ozlem; Bozcu, Mustafa; Ozturk, Muhammed Zeynel; Selim, Haluk Hamit; Nowacyzk, Norbert R.Climate changes determined the repeated connections between the Black Sea, Caspian Sea and Mediterranean Sea. The landlocked anoxic Black Sea basin was exposed to several transgressions throughout Quaternary by the Mediterranean Sea through the Straits of Istanbul (Bosphorus) and by the Caspian Sea through the Manych-Kerch spillway. Sedimentological records of these connections are limited mostly to the marine terrace deposits of Marine Isotope Stage (MIS) 5e while the pre-MIS 5e period remains uncertain due to a lack of robust facies and chronological data from deep-sea sedimentary sequences. Here we discuss the imprints of multiple Mediterranean transgressions during Middle Pleistocene in the Black Sea based on facies analysis and the optical age of coastal carbonate aeolianites. Contrary to today's hydro-climate of the Black Sea, the aeolianites bear witness to the transformation of the Black Sea into a warm inland sea during successive Mediterranean invasions. Prior to the onset of aeolian deposition, paleosols were formed on the Eocene-aged hardened sandy silts, suggesting strongly washed soil. This is evidenced by no calcium carbonate and a high Rb/Sr ratio, with quartz amounting to of 99.8%. According to our OSL ages, carbonates deposited on the shelf plain under higher temperature and increased evaporation conditions in MIS 15 and the later interglacial phases were transported to the coastal sand dunes during the transitional phases of MIS 15-14, MIS 13-12, MIS 11-10 and MIS 9-8. We suggest that the carbonate-rich and ooid-containing aeolianites were repeatedly formed in the multiple Mediterranean transgression stages, beginning with an increasingly severe dry phase following the Brunhes-Matuyama magnetic reversal.Öğe Cement fabrics and optical luminescence ages of beachrock, North Cyprus: Implications for Holocene sea-level changes(PERGAMON-ELSEVIER SCIENCE LTD, 2016) Ozturk, Muhammed Zeynel; Erginal, Ahmet Evren; Kiyak, Nafiye Gunec; Ozturk, TugbaCaCO3-cemented beachrocks are widely found along the northern coast of Cyprus. In this study, we aim to discuss the cementation history of beachrocks at ten particular sites within the context of Holocene sea-level changes. Cement fabrics, petrographic and geochemical characteristics, and optically-stimulated luminescence ages of buried quartz grains were studied. The seaward-inclined (similar to 5-10 degrees) parallel-stratified beds are composed mostly of sandstone alternating with conglomerate. Ooids, benthic and planktic foraminifera, bioclasts of red algae, echinoid spines and gastropods make up a significant proportion of the cemented beds. With CaCO3 content ranging between 37% and 65%, poorly-sorted grains are bonded by four distinct cements: circumgranular micritic coatings, sparry calcite infillings, pore fills, and meniscus bridges. This consecutive nature of cementation is typical of a marine phreatic and meteoric vadose environment when the sea level was lower than present but had a tendency to increase during middle to late Holocene. OSL ages ranging from 5.4 ka to 0.38 ka indicate that the deposition and ensuing cementation of the quartz grains occurred during two main stages; younger beds dated between 2.3 ka and 0.38 ka and older beds from 2.3 ka to 5.4 ka. A period devoid of beachrock formation was attested between 3.5 ka and 2.3 ka. (C) 2015 Elsevier Ltd and INQUA. All rights reserved.Öğe Climate Types of Turkey According to Koppen-Geiger Climate Classification(Istanbul Univ, Fac Letters, Dept Geography, 2017) Ozturk, Muhammed Zeynel; Cetinkaya, Gulden; Aydin, SelmanThe Koppen-Geiger climate classification is one of the most widely used climate classification method. Climate zones are determined depending on monthly temperature and precipitation data and are indicated by letters. In this study, the Koppen-Geiger climate zones of Turkey were determined by analyzing the data collected from 512 meteorological stations. The climate characteristics of the determined climate types are explained via climate diagrams. According to the Koppen-Geiger climate classification, temperate climate (C) has the largest area, whereas arid climate (B) has the narrowest area.The widespread type B climate is observed in Central Anatolia, whereas type C climate is dominant in the coastal regions. Continental climate (D) is observed in the highlands of the Central Taurus and almost all of the Eastern Anatolia regions. According to the second and third letters, 10 different subclimate types were observed for B, C, and D climate types in Turkey. All these sub-types indicate that climates that do not have hot or cold dry seasons are dominant in Turkey. However, the northern parts of Turkey do not experience a dry-season climate.Öğe Comparison of morphometric characteristics of dolines delineated from TOPO-Maps and UAV-DEMs(Springer, 2023) Utlu, Mustafa; Ozturk, Muhammed ZeynelDolines are the characteristic landforms in karstic landscapes, and their morphometric characteristics are commonly used for surface karst research. More than 140,000 dolines were identified using 1:25,000 scale topographic maps (TOPO-Maps) in the West and Central Taurus, Turkiye's most important karst terrain. However, the accuracy of these TOPO-Maps in terms of real morphometric characteristics of dolines in the Taurus Mountains is unknown. For this reason, in this study, dolines were automatically delineated from high-resolution digital elevation models (DEMs) produced by unmanned aerial vehicles (UAV-DEMs), and their morphometric characteristics were compared with the results obtained from 1:25,000 scale TOPO-Maps. UAV-DEMs with resolution below meter level provide a more accurate representation of the real Earth surface and thus landforms can be examined in more detail. In this study, six locations covering a total of 8.03 km(2) were modeled with UAV. According to the results, the accuracy of the TOPO-Maps in terms of doline numbers was 0.24 (24%)-0.98 (98%), and this rate increased as the average area of the dolines increased. Doline density was always high with UAV-DEM data, and doline density had an average 99% increase when compared with TOPO-Map data. Due to UAV-DEMs providing the opportunity to calculate more morphometric characteristics, in this study, we provide information for the first time about the depth, slope, and volume characteristics of dolines in the Taurus Mountains. The mean depth, slope, and volume of solution dolines were 31 m, 45 degrees, and 207,931 m(3) in the Taurus Mountains, respectively.Öğe Controls on long-term denudation rate of carbonate terrains in the Eastern Mediterranean(Pergamon-Elsevier Science Ltd, 2023) Hashemi, Ayda; Sarikaya, Mehmet Akif; Wilcken, Klaus M.; Ozturk, Muhammed ZeynelQuantifying denudation rates under different climatic and tectonic settings is fundamental to understanding landscape evolution. Carbonate rocks may respond differently to climatic and tectonic forcings than other rock types because of their tendency to dissolve congruently. Yet, there is little information on the long-term denudation rate of carbonates and their controlling factors in different settings. Here, we present the first long-term denudation rates for carbonates in the south of the Central Anatolian Plateau. We quantified the outcrop denudation rates using in-situ cosmogenic 36Cl measured in 13 rock samples to evaluate spatial variations and potential controls on the style and rate of denudation. 36Cl-derived denudation rates range from 1.92 +/- 0.31 to 45.77 +/- 3.91 mm/ka. On the plateau, denudation rates are strongly correlated with precipitation and are lower than the theoretical maximum dissolution rates predicted assuming zero evaporation, implying that climate exerts the major control on carbonate denudation. These results indicate that chemical weathering is the prevalent denudation style. The denudation pattern shows spatial variability with a decreasing trend from SW to NE consistent with climate zones. High-to-moderate denudation rates occur in the continental climate, while the lowest denudation rates occur in the arid plateau interior. In the Mediterranean coastal region, measured denudation rates are higher than the predicted maximum dissolution rates, reflecting the mechanical removal of overlying rock or soil. The low denudation rates in the plateau interior indicate a slowly evolving landscape with an arid climate. The physical properties of rocks showed the weakest control on carbonate denudation. In the Central Taurides, significant infiltration of surface runoff resulted in strong subsurface karstification at the expense of surface drainage. This process caused disequilibrium between uplift and denudation and resulted in the preservation of high-elevation topography. Therefore, in the actively uplifting plateau margin, the influence of tectonics on carbonate denudation has been interfered with the impact of precipitation and subsurface karstification.Öğe Depositional environment characteristics of UlukA +/- AYla Evaporites, Central Anatolia, Turkey(SPRINGER, 2017) Keskin, Seref; Sener, Mehmet; Sener, Mehmet Furkan; Ozturk, Muhammed ZeynelThis paper examines evaporated deposits of gypsum known as the UlukA +/- AYla Evaporites located in the UlukA +/- AYla Basin, central Anatolia, Turkey. The Late Eocene compression between the Eurasian and Afro-Arabian plates formed numerous shallow epicontinental basins in SE central Anatolia. During this period, the UlukA +/- AYla Basin was a shallow marine environment. The composition of the UlukA +/- AYla Basin indicates that gypsum and stromatolite were deposited due to an arid climate and sea level oscillation between 37.25 and 38.52 Ma. Oxygen, sulfur, and strontium isotopes and the geochemistry of the evaporated rocks were measured to understand the paleoenvironment of this formation. Trace element analyses of Fe, K, Mg, Na, Mn, Sr, Ni, and Cu from the gypsum samples showed very high variability. The average K/Na, Sr/Ca, and Mg/Na were measured to be 0.4, 2.35, and 2.9 %, respectively, which indicates that the UlukA +/- AYla gypsum lies in a formerly hypersaline environment. Sr-87/Sr-86, O-18, and S-34 isotope ratios indicate that the gypsum was deposited in marine water then mixed with fresh continental water.Öğe Did Amphistegina lobifera Larsen reach the Mediterranean via the Suez Canal?(PERGAMON-ELSEVIER SCIENCE LTD, 2016) Meric, Engin; Yokes, M. Baki; Avsar, Niyazi; Kiyak, Nafiye Gunec; Oner, Ertug; Nazik, Atike; Ozturk, Muhammed ZeynelIt has been accepted by many researchers that Amphistegina lobifera Larsen migrated to the Mediterranean Sea via Suez Canal like many other Indo-Pacific originated foraminifers and organisms. This idea was also supported in the studies performed on the Turkish Aegean and Mediterranean coast in the last ten years, due to the discovery of alien benthic foraminifers. However, during field research in the Akkuyu (Mersin) region, a rich benthic foraminifera assemblage was found in the sediment samples, in which Amphistegina lobifera Larsen was abundant. In the present study, when and how Amphistegina lobifera Larsen migrated to the Mediterranean was investigated. Most of the Amphistegina lobifera Larsen individuals observed are found to show similar morphological characteristics with recent samples collected from Turkish coastline, which at first indicated that the individuals from Akkuyu might also be of Holocene age, but the OSL method produced dates of 227.3 +/- 17.8, 87.7 +/- 9.6 and 6.0 +/- 0.6 ka. These ages are Middle Pleistocene, Late Pleistocene and Holocene. In one sample, aged 427.5 +/- 29.4 ka, Spiroloculina antillarum d'Orbigny, which was suggested to be introduced to Mediterranean via the Suez Canal, was found together with Articulina carinata Wiesner. The presence of Spiroloculina antillarum d'Orbigny with Amphistegina lobifera Larsen together with in an other sample, aged 227.3 +/- 17.8 ka, indicates that these foraminifers have been introduced to the Mediterranean in Middle Pleistocene and they might have been living in the Eastern Mediterranean since then. As a result, these age data show that Amphistegina lobifera Larsen individuals did not migrate to the eastern Mediterranean via the Suez Canal which was opened in 1869, but much earlier than that via a different natural water way connecting Indo-Pacific to the Eastern Mediterranean. (C) 2015 Elsevier Ltd and INQUA. All rights reserved.Öğe Drainage Characteristics of the Cappadocia Region(Istanbul Univ, Fac Letters, Dept Geography, 2019) Ozturk, Muhammed Zeynel; Ozkan, Demet; Simsek, MesutThe morphology of the widespread badlands in the region of Cappadocia has mainly been the result of erosional processes on ignimbrite and tuff formations. Fairy chimneys are the most characteristic landforms of badlands morphology and many factors are responsible for the formation of these landforms in the region. Bedding, hardness and porosity of ignimbrites, shape, size and frequency of discontinuities in ignimbrites, slope, climate and drainage properties etc. of the area all significantly contribute to the development of badlands and fairy chimneys. In this study, drainage properties, which are one of the main controlling factors in this development, were investigated referencing 1/25.000 scale topography maps. Firstly, all valley thalwegs were digitized using GIS. Subsequently, the Strahler order numbers of each stream were determined, and a drainage density map was created. Basing our results on maximum drainage densities, the highest drainage density (15.3 km/km(2)) in the study area was identified in ignimbrite and tuffs in the Goreme National Park, whilst, the lowest drainage densities were located on plateau surfaces (basalt (9 km/km(2)), dacite (4.2 km/km(2)) and andesite (3.2 km/km(2)) in the southern part of the study area. According to the Strahler order method, 53% and 22.7% of all streams belong to first and second orders, respectively. All these results show that drainage conditions on ignimbrite and tuffs are determinant factors in the formation of both badlands morphology and fairy chimneys.Öğe Electrical Resistivity Technique On The Investigation Of Subsurface Structure Of Fossil And Beach Dunes And Its Contributions To The Interpretation Of Paleo-Coastal Environment(TMMOB JEOLOJI MUHENDISLERI ODASI, 2015) Demirci, Alper; Ekinci, Yunus Levent; Erginal, Ahmet Evren; Ozturk, Muhammed ZeynelBased on the technological progress, the improvements of the software packages and multi-electrode measuring systems have enabled to perform the Electrical Resistivity Tomography (ERT) measurements more widely, faster and more reliable in various disciplines of earth sciences. Herein, some recent case study examples performed by ERT technique for uncommon-purposes such as investigation of coastal environs are presented. Imaging the lower parts of the beach and dune sands (or other covering units) of layered coastal deposits, which were cemented with calcium carbonate after the development by the control of wave, current and wind, and also the buried geological structures and fossil topographies covered by those beach and dune sands, shows significant contribution of ERT technique on the investigations of coastal geology and paleogeography. Thus some case studies, which have been performed in Black Sea (Sile, Karaburun, Kiyikoy) and Aegean Sea (Bozcaada Island) coasts, and their findings were presented here. The depositional characteristics, subsurface geometry and contact relations of those fossil coastal deposits cemented on different geological periods from Late Pleistocene to Late Holocene provide noteworthy contributions in understanding regarding sea level changes, paleo-wind and current dynamics. The derived-ERT images obtained from the field studies yielded key information about the depositional nature of the deeper parts of the studied layers.Öğe Eolianite and coquinite as evidence of MIS 6 and 5, NW Black Sea coast, Turkey(Elsevier Sci Ltd, 2017) Erginal, Ahmet Evren; Kiyak, Nafiye Gunec; Selim, Hamit Haluk; Bozcu, Mustafa; Ozturk, Muhammed Zeynel; Ekinci, Yunus Levent; Demirci, AlperThis paper discusses the implications of a lowstand carbonate eolianite and overlying transgressive sequence of coquinite at Sile on the Turkish Black Sea coast based on composition, depositional characteristics and optical age estimations. The cross-bedded eolianite is a mixed ooid quartz grainstone in composition, yielding a depositional age matching MIS 6. It formed at the backshore of the paleobeach with the supply of sediment the from the beach face and offering insights into the drift of mixed shallow marine carbonates and siliciclastics together with radial ooids by onshore winds from a subaerially exposed high- to low-energy ooid shoals and oolitic sand complexes which developed parallel to the shoreline on the shallow shelf margin. During this lowstand, a low-relief dune retaining a record of opposing paleowind directions than that of prevalent northeasterly winds of today appears to have been lithified to form dune rock (aeolinite) under drier conditions compared to the present. Coinciding with MIS 5e, shallow marine coquina beds resting unconformably on the eolianite indicate the occurrence of the Mediterranean transgression during the last interglacial, as confirmed by benthic foraminifera within the high-salinity tolerant coquina shells. (C) 2017 Elsevier B.V. All rights reserved.Öğe Fluvio-karstic evolution of the Taseli Plateau (Central Taurus, Turkey)(Tubitak Scientific & Technological Research Council Turkey, 2020) Ozturk, Muhammed ZeynelUplift history is an important factor in the structural patterns and karstification of the Taseli Plateau. The morphological development of the study area consists of five stages according to its sedimentation, rotation, uplift, and climatic properties. (1) Shallow carbonates accumulated during the Early Miocene. (2) An emersion and drainage network developed as a result of the compressional neotectonic regime in the Late Miocene. (3) Dense joint systems were formed due to the similar to 40 degrees clockwise rotation of the eastern limb of the Isparta Angle. (4) The climate of the study area changed as a result of rapid uplift from Late Pliocene to Early Pleistocene. This caused the formation of dry valleys, underground karstification on the plateau surface, and headward erosion of rivers in the southern part of the area. (5) In the last stage, the plateau surface was densely covered by solution dolines and the dry valley network turned into relict valleys due to expanding extensional cracks during Pleistocene.Öğe GIS based analysis of doline density on Taurus Mountains, Turkey(Springer, 2018) Ozturk, Muhammed Zeynel; Simsek, Mesut; Sener, Mehmet Furkan; Utlu, MustafaThe Taurus Mountain is one of the most important karstic region of the world and dolines are characteristics landforms of this area. However, the number and distribution of doline are unknown in the study area. The aims of this study are to explain the total number of dolines, distribution of doline density, effects of slope conditions and the change of doline orientation in the Taurus Mountains. According to the 1/25000 scale topographic maps utilized in this study, a total of 140,070 dolines were determined in a 13,189 km(2) area on eleven high karstic plateaus bordered by steep slopes and deep gorges. These plateaus are substantially affected by highly-faulted and jointed systems and about 80% of each plateau is covered with neritic limestone. The dolines are located at an elevation between 10 and 2870 m. Average elevation of all dolines is 1842 m. 90% of dolines are located between 1300 and 2270 m and only 5% of dolines found under 1330 m. According to this results, the densest doline zone corresponds to the alpine and periglacial zone above the treeline. Doline density reaches > 100 doline/km(2) on Mt. Anamas and the Seyran, Geyik and Akdag ranges as well as the TaAYeli plateau. Maximum density (187 doline/km(2)) is found on the Akdag Mountains. However, 66% of the study area is characterized by low density, 29.9% with moderate density, 3.4% with high density and 0.7% with very high density. The highest doline densities are seen on gentle slopes (15A degrees-25A degrees/km(2)) and steep slopes (> 35A degrees/km(2)) are limited doline distribution. According to the rose diagram formed by the azimuths of the long axis of the dolines at the Central Taurus, two direction are dominant in doline orientations (NW-SE and NE-SW). However, dominant directions are NE-SW at eastern, NE-SW and NW-SE at central and NW-SE at western part of the Central Taurus. According to this elongations, doline orientations are formed an arc which is formed by tectonic evolution of the Central Taurus.Öğe High Resolution Köppen-Geiger Climate Zones of Türkiye(Wiley, 2024) Tasoglu, Enes; Ozturk, Muhammed Zeynel; Yazici, OznurThe K & ouml;ppen-Geiger (K-G) climate classification is the most commonly used climate classification method in the world, and there are many K-G climate classification studies focusing on T & uuml;rkiye using different datasets. However, the differences in the datasets used in these studies lead to substantial differences and errors in K-G climate zone maps. The differences and disagreements in these maps also cause significant discrepancies in climate studies. In this respect, accurate identification of climate classes and types is very important for understanding the distribution of climate types and for many climate-based studies to achieve accurate results. In this study, the K-G climate types of T & uuml;rkiye and the regime characteristics of these climate types were determined using the CHELSA dataset corrected based on the measurements of 337 meteorological stations. According to the results that were obtained, 14 climate types were identified in T & uuml;rkiye. Since the CHELSA dataset reflected topographic conditions well, many microclimates were identified within broad areas of climate types. The distribution of the microclimate types was compared to the distribution of the vegetation, and the accuracy of the results was evaluated. Apart from microclimates, other prominent features of this study were the co-occurrence of multiple climate types in a limited area in the Eastern Black Sea Region and the detection of the EF climate type for the first time at the summit of Mount Ararat. Climate types vary according to altitude conditions, and temperature changes due to altitude are an important factor in the formation of climate sub-types within the same main climate type in T & uuml;rkiye. In this study, precipitation and temperature values in the CHELSA database were modified by using meteorological station records and K & ouml;ppen-Geiger climate zones map of Turkey was produced.imageÖğe Morphometric Analyses of Karstic Depressions (Dolines)(Istanbul Univ, Fac Letters, Dept Geography, 2018) Ozturk, Muhammed ZeynelDolines (karstic closed depressions) are surface landforms that are characteristic of karstic areas. Since tectonic, morphologic, and climatic features greatly affect doline development, morphology, and distribution, dolines can provide important information about the morpho-tectonic evolution of karstic areas. Although there are many calculations used in determining doline morphometry, but only a few are common. In this study, we review the parameters commonly used in determining doline morphometry and offer examples from around the world, specifically the Taurus Mountains.Öğe Morphometric characteristics and paleogeographic implication of glacial cirques in Eastern Black Sea Mountains (Turkiye)(Elsevier, 2023) Simsek, Mesut; Ozturk, Muhammed Zeynel; Yesilyurt, Serdar; Utlu, MustafaThe Eastern Black Sea Mountains, located in the northeastern region of Anatolia and running parallel to the Black Sea coast, underwent glaciation during the Quaternary. The mountain range contains 811 cirque sites. Although the majority of the cirques are simple, 309 are complex, according to their developmental features. In Anatolia, intensive cirque development is observed only on north-facing slopes in several mountains, while in the Black Sea Mountains, 66.5 % of the cirques are located on north-facing slopes and 14.5 % on south-facing slopes. Differences in cirque morphometry between the north- and south-facing slopes were primarily influenced by aspect, which had a significant influence on Quaternary glaciation. While the northwest-facing cirques are the largest, the east- and southeast-facing cirques are the smallest. This situation is related to that air masses that bring rain to the mountains generally come from the northwest. The mean cirque floor elevation is 2815 m, while 90 % of the cirques have floor elevations between 2479 and 3130 m. In light of these measurements, the former Equilibrium Line Altitude (ELA), initially positioned above 2480 m, underwent a complete stabilization at elevations exceeding 2800 m within the Black Sea Mountains. However, these averages are not sufficient to represent the former ELA across the mountain. According to the cirque floor elevations, the cirques in the Nsector have a mean elevation of 2760 m, while the cirques in the S-sector have a mean elevation of 3004 m, and there is a 244 m difference between the two sectors. In the NW basin, the cirques start at 2434 m and reach a permanent former ELA level at 2743 m. In the SE basin, on the other hand, the cirques start at 2635 m and become permanent at 2920 m. Aspect had a significant effect on the distribution of other morphological elements associated with the cirques. The N-sector cirques harbor 73.5 % of the cirque lakes and 81.8 % of the rock glaciers. The average depth of the cirques in the northern sector stands at 388 m, whereas it diminishes to 341 m in the southern sector. Negative correlations emerge between former ELA levels and both latitude and distance from the watershed, while positive correlations align with distance from the coast. Based on these correlations and the associated distribution maps, a clear trend emerges: the former ELA diminishes as one travels north, approaches the coast, and encounters decreasing topographic elevations.Öğe Morphometric Properties of Poljes in the Taurus Mountains, Southern Turkey(Istanbul Univ, Fac Letters, Dept Geography, 2021) Simsek, Mesut; Ozturk, Muhammed Zeynel; Dogan, Ugur; Utlu, MustafaPoljes, which represents the largest and relatively the most complex karst forms, are one of the most characteristic and widespread features in the karst terrains of the Taurus Mountains. Although poljes have been one of the most studied landforms in the Anatolian karst, except for a few studies, no particular attention has been directed to provide a quantitative study on the morphometry and spatial distribution of poljes. In this study, an attempt has been made to present a comprehensive account of the basic morphometric characteristics and spatial distribution of the poljes within the karst regions in the Taurus karst belt, based on the critical review of the previous literature and detailed map studies. In this respect, 680 topographic maps, 1;25.000 scales with 10 m contour intervals, were analyzed and the 175 poljes were mapped. A data set based on the determination of morphometric parameters of the poljes was prepared, including X and Y centroid coordinates, the elevation of the floors above mean sea level, area, perimeter length, short and long axis lengths, elongation ratio, and circularity index. Within the scope of this dataset, the spatial distribution of the basic morphometric properties of poljes and the main factors controlling these properties were evaluated and interpreted. Most of the poljes in the Taurus karst belt are found in the area within the Isparta Angle located in the Western and Central Taurus. Most of the polje floor elevation (90%) is about between 447 and 1865 m above mean sea level though they are distributed in various elevations. Some poljes cover rather large areas, but the majority (65%) of them have a surface area of not more than 10 km sq. Due to the hydrological and tectonic characteristics of poljes, the circularity index values increase up to 28 and the elongation ratio values up to 9. The circularity index reaches higher values in fluvio-karst poljes dominated by fluvial processes, whereas the elongation ratio is higher in tectonically controlled poljes.Öğe Morphotectonic development of surface karst in Western Taurus (Türkiye)(Springer, 2023) Sener, Mehmet Furkan; Simsek, Mesut; Utlu, Mustafa; Ozturk, Muhammed Zeynel; Sozbilir, HasanThe Taurus Mountains, the most important karst terrains of Turkiye, contain many surface and subsurface karst landforms, and the morphometric features of these landforms provide important data on the geomorphological and morphotectonic development of karst areas in the Taurus Mountains. Micro and macro karst depressions are the most important surface landforms in the Western Taurus Mountains. In this study, a total of 7093 micro depressions (doline) and 74 macro depressions (polje) located in the Western Taurus Mountains were detected and morphometric properties were calculated. The poljes developed within the Beydaglari Autochthon and Lycian nappes, while the dolines developed mainly in the high karst plateaus within the Beydaglari Autochthon. As briefly described below, the morphotectonic evolution of both landforms is closely related to the tectonic evolution of the Western Taurus Mountains. As a result of this tectonic activity, the Lycian Nappes from the northwest and the Antalya Nappes from the east thrust over the Beydaglari autochthon, leading to the development of nappes, reverse faults, and fold systems in the study area. The Western Taurus began terrestrialization starting from the Oligocene and began to erode from the Miocene. This erosion process led to the development of valley systems within the Western Taurus region. The NE-SW and NW-SE directional normal faults have developed under the influence of extensional tectonics since the Miocene. This extensional tectonism has caused widespread development of the poljes in the study area. Furthermore, with the lowering of the karst base level, dolines and paleovalleys began to develop in limestone areas at higher elevations. All morphometric and morphotectonic processes reveal that the extension of both doline and polje areas in the study area are parallel to the elongation of tectonic structures in the Western Taurus.Öğe Records of repeated drought stages during the Holocene, Lake Iznik (Turkey) with reference to beachrock(PERGAMON-ELSEVIER SCIENCE LTD, 2016) Ozturk, Muhammed Zeynel; Erginal, Ahmet Evren; Kiyak, Nafiye Gunec; Demirci, Alper; Ekinci, Yunus Levent; Curebal, Isa; Ozturk, TugbaThe cement fabrics, subsurface nature and optically stimulated luminescence age of beachrocks along the shores of Lake Iznik in NW Turkey were studied within the context of Holocene lake level changes. With a maximum thickness of 1.5 m, the low-angle (average 5-10 degrees) beds are composed of coarse grains and small gravels and extend up to 5 m offshore at their most lakeward extremities. Cement textures on and around the poorly-rounded grains are made up of micrite envelopes and meniscus bridges as well as acicular aragonite rims. Geoelectrical resistivity sections taken from a representative location along the beach where the beds have maximum thickness showed that the sand-buried beds are followed up to about 24 m landward. Based on the OSL ages of 33 samples, the cemented beds occurred at four drier periods of the following: Pre- and Early Holocene (dated to 15-9 ka), Holocene Climatic Optimum (7.9-5.6 ka), Middle Holocene (4.9 ka-2.8 ka) and Late Holocene (2.0 ka-0.9 ka). (C) 2015 Elsevier Ltd and INQUA. All rights reserved.Öğe Structural controls on distribution of dolines on Mount Anamas (Taurus Mountains, Turkey)(Elsevier Science Bv, 2018) Ozturk, Muhammed Zeynel; Sener, Mehmet Furkan; Sener, Mehmet; Simsek, MesutSolution dolines are characteristic landforms on the high plateaus of the Taurus Mountains. In this study, the effects of tectonic structures, drainage and slope conditions on the distribution and morphometric properties of dolines in the western part of the Central Taurus are explained. To delimit the dolines, 1/25000 scale topographic maps were used. The uppermost closed contour lines were digitized as polygons and the elevation, long and short axes, elongation ratios, orientation angles of the polygons were calculated. The doline density is compared with drainage density and mean slope values. A total of 111 rose diagrams were created in order to illustrate the superficial distribution of orientation. As a result, a total of 10,652 dolines were detected in a 711 km(2) doline area and maximum density reaches 123 dolines/km(2). However, according to the doline density, two distinct regions were detected, high density (RI) and low density (R2). Correlations between drainage density, slope angle and doline density are negative in the two regions. According to negative correlations, the drainage density is not a determinant factor in RI, while it is a determinant factor in R2. A 30 degrees slope angle (in km2) limits doline distribution on the plateau surface. The orientation of all doline long axes is NW-SE, which is parallel to the general orographic extent of Mount Anamas. However, different orientations were detected and these orientations were showed in farther sub-regions according to the 111 gridded rose diagrams. The overall result of this study is that the fault and joint systems that developed on the thick-bedded limestone between thrust faults affected the doline density, while lateral strike-slip, normal faults and joint systems in front of the thrust belt were more effective on the geometric shapes of dolines. (C) 2018 Elsevier B.V. All rights reserved.
