Yayınlar
Koleksiyondaki öğeler
- MakaleYalnız künye2018Scopus SJRQ2Adsorption of Cu(II) ions from aqueous solution by hazelnut husk activated carbon prepared with potassium acetate
Imamoglu, Mustafa; Ozturk, Asuman; Aydın, Şeyma; Manzak, Aynur; Gündoğdu, Ali; Duran, Celal
Hazelnut husk (HH), an agricultural waste, was converted to carbonaceous material by chemical activation using potassium acetate. The produced activated carbon (KAHHAC) was characterized by FTIR, SEM, N2 adsorption–desorption experiments, CHN elemental analysis, and determination of moisture, ash, and point of zero charge. KAHHAC was used for the batch adsorption of Cu(II) ions from aqueous solutions. Optimum pH and contact time were found to be 5.0 and 240 minutes, respectively. The adsorption equilibrium data were described well by the Langmuir equation providing 105.3 mg g−1 Cu(II) adsorption capacity. The pseudo-second-order model successfully described the kinetic of Cu(II) adsorption by KAHHAC. The adsorbed Cu(II) onto KAHHAC was completely desorbed by 0.5 M nitric acid. In conclusion, HH activated carbon (AC) produced by the potassium acetate activation method is a very useful and efficient sorbent material for the removal of Cu(II) from aqueous solution.
AtıfScopus20WoS17OpenAlex20
İncele - MakaleYalnız künye2016Scopus SJRQ2Simplified Early Stopping Criterion for Belief-Propagation Polar Code Decoders
Simsek, Cemaleddin; Turk, Kadir
As the first theoretically proven capacity-achieving error correction code, polar codes have become a milestone in information theory field, which draw serious attention by its low complexity encoding and decoding structures. For the decoding section, studies are focused on efficient and low complex algorithms based on successive cancellation and belief-propagation (BP) decoders. To reduce computational complexity of BP-based decoders further, early stopping methods that avoid unnecessary iterations can be used. In this letter, we propose a reduced complexity early stopping method for BP-based polar code decoders. The proposed method is based on the hypothesis that observing only a small cluster of information bits polarized to the highest error probabilities is enough to detect successful decoding. Simulation results show that the proposed early stopping criterion significantly reduces the computational complexity of successful decoding detection as well as the total operation numbers of the whole decoding process compared with previous methods in the literature.
AtıfScopus45WoS41OpenAlex47İncele - BildiriAçık Erişim2016A Study on the Performance of GPR for Detection of Different Types of Buried Objects
Toksoz, Derya; Yilmaz, Isik; Seren, Aysel; Mataraci, Isil
The objective of this research is to evaluate the applicability of Ground Penetrating Radar (GPR) method to detect burried objects in the shallow depths using 250 MHz and 800 MHz center frequency antennas. For this purpose, different objects were burried in several places of a certain test site. GPR data were collected along six paralel profiles using 250 MHz and 800 MHz antennas which are compatible with RAMAC CU II system. The reflections profile data were processed using the computer program ReflexW. After the processing of data, the reflected /scattered reflections on the processed radargrams were examined and the radargrams were interpreted to determine the depths and positions of the objects from the surface. Also, the data obtained from 250 and 800 MHz antennas were compared and the differences between them in terms of resolution were discussed.
AtıfScopus7WoS2OpenAlex4İncele - MakaleYalnız künye2017Scopus SJRQ2The Stranger to Time: What a Collector Stands for in a Hurried Society
Demir, Sertaç Timur
City-dwellers who are threatened by the risk of natural or social disasters are in search of safer houses. Each attempt to satisfy their need for safety, however, turns into another version of the security problem; so much so that, escaping from risk itself turns into different (yet nevertheless more powerful) risks. The film 10 to 11 (2009) focuses on the socio-spatial conflict between a stranger and his neighbours who are anxious about a possible earthquake risk in Istanbul. Mithat, the protagonist of the film, is a stranger not only to place but essentially to time. He lives within time and understands place as an essential means loaded by temporal experiences and memories. This paper deals with the multiple dichotomies between time and memory, between risk and fear, between aesthetics and security, and between attachment and profit in the context of urban transformation. The stranger, who is analysed for the first time as a temporal being in this paper, is discussed using Zygmunt Bauman’s concepts of uncertainty and liquid modernity, Richard Sennett’s capitalism, Ulrich Beck’s risk society, Frank Furedi’s culture of fear, Stephen Bertman’s hurried culture, Elias Canetti’s death, Giorgio Agamben’s forgotten and gone, Svetlana Boym’s nostalgia, and Halbwachs, Assmann, Connerton, and Arendt’s memory, as well as around the temporal spaces of museums, bibliopoles, antique shops, and cemeteries.
AtıfWoS1OpenAlex2İncele - MakaleYalnız künye2016Scopus SJRQ1Logistics center site selection by ANP/BOCR analysis: A case study of Turkey
Peker, Iskender; Baki, Birdogan; Tanyas, Mehmet; Murat Ar, Ilker
Site selection for logistics centers is one of the most strategic decisions in logistics. This study addresses the problem of logistics center site selection, using Analytic Network Process/Benefits, Opportunities, Costs and Risks, which is a multi-criteria decision making technique. The decision problem is applied to the city of Trabzon, which is an important city of the Eastern Black Sea Region in Turkey. First, the results are evaluated in terms of each sub-network and each group and, next, are consolidated for each alternative. They yield that Alternative A is the most appropriate logistics center location of all in Trabzon. Furthermore, the sensitivity analysis results emphasize that the decision model is robust.
AtıfScopus40WoS34OpenAlex45İncele - BildiriAçık Erişim2016The comparison of performance by using alternative refrigerant R152a in automobile climate system with different artificial neural network models
Kalkisim, A.T.; Hasiloglu, A.S.; Bilen, K.
Due to the refrigerant gas R134a which is used in automobile air conditioning systems and has greater global warming impact will be phased out gradually, an alternative gas is being desired to be used without much change on existing air conditioning systems. It is aimed to obtain the easier solution for intermediate values on the performance by creating a Neural Network Model in case of using a fluid (R152a) in automobile air conditioning systems that has the thermodynamic properties close to each other and near-zero global warming impact. In this instance, a network structure giving the most accurate result has been established by identifying which model provides the best education with which network structure and makes the most accurate predictions in the light of the data obtained after five different ANN models was trained with three different network structures. During training of Artificial Neural Network, Quick Propagation, Quasi-Newton, Levenberg-Marquardt and Conjugate Gradient Descent Batch Back Propagation methodsincluding five inputs and one output were trained with various network structures. Over 1500 iterations have been evaluated and the most appropriate model was identified by determining minimum error rates. The accuracy of the determined ANN model was revealed by comparing with estimates made by the Multi-Regression method.
AtıfScopus1OpenAlex2İncele - BildiriYalnız künye2016Determination of the dynamic characteristics of the faculty building of law at KTU campus with HVSR and FSR methods
Bekar, Y.; Coban, K.H.; Sayil, N.
Seismic response characteristics of structures can be estimated by spectral ratios of microtremors measured on structures and their foundation ground surface. The microtremor horizontal-To-verticalspectral- ratio (HVSR) technique has received great attention from all over the world with its simplicity together with quick information about dynamic characteristics of ground and structures. The HVSR of microtremors gives a good estimation of natural building frequency. In this study, Horizontal-To-Vertical- Spectral-Ratio HSVR method and Floor Spectral Ratio Method (FSR) has been applied to microtremor records taken with three component broad band velocity seismometers in three different locations inside the building and one at outside with the aim of determining the dynamic characteristics of Faculty building of Law at The Karadeniz Technical University (KTU), in Turkey. The average predominant frequency, period and amplification values for the Faculty building of Law are calculated. The vibration frequency and period is around 3.5 Hz and 0.283 s, respectively. The amplitude values increase to the upper floors.
- MakaleYalnız künye2017Scopus SJRQ4Continuity of superposition operators on the double sequence spaces of maddox L(p)
Güngör, Nihan; Sağır, Birsen
Petranuarat and Kemprasit (Southeast Asian Bull Math 21:139–147, 1997) characterized continuity of the superposition operator acting from the sequence space lp into lq where 1 ≤ p, q < ∞. Sağır and Güngör defined the superposition operator Pg by Pg(x) = (g(k, s, xks))∞k,s=1 for all real double sequences (xks) where g: N2 × R → R and gave continuity of the superposition operator acting from the double sequence spaces Lp into Lq for 1 ≤ p, q < ∞. In this paper, we characterize the continuity of the superposition operator acting from Maddox double sequence spaces L(p) into L(q)where p = (pks) and q = (qks) are bounded double sequences of positive numbers.
AtıfScopus1WoS1OpenAlex2İncele - MakaleAçık Erişim2016Scopus SJRQ2Kinetic and in silico studies of hydroxy-based inhibitors of carbonic anhydrase isoforms I and II
Ekhteiari Salmas, Ramin; Mestanoglu, Mert; Durdagi, Serdar; Sentürk, Murat; Kaya, A. Afşin; Kaya, Elif Çelenk
A series of hydroxy and phenolic compounds have been assayed for the inhibition of two physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isozymes, the cytosolic human isozymes I and II. The investigated molecules showed inhibition constants in the range of 1.07-4003 and 0.09-31.5 μM at the hCA I and hCA II enzymes, respectively. In order to investigate the binding mechanisms of these inhibitors, in silico studies were also applied. Molecular docking scores of the studied compounds are compared using three different scoring algorithms, namely Glide/SP, Glide/XP and Glide/IFD. In addition, different ADME (absorption, distribution, metabolism and excretion) analysis was performed. All the examined compounds were found within the acceptable range of pharmacokinetic profiles.
AtıfScopus10WoS11OpenAlex15
İncele - MakaleYayıncıda açık erişim2019Scopus SJRQ2The investigation of different chicane applications in traffic calming studies using driving simulator; [Trafik sakinlestirme çalismalarinda farkli kivrimlama uygulamalarinin sürüş simülatörü ortaminda incelenmesi]
Aydin, Metin Mutlu; Akgöl, Kadir; Günay, Banihan
High vehicular speeds are one of the most frequent complains in urban roads. Lack of obedience to speed limits results in many fatal accidents. Traffic calming measures have been widely used in many developed countries to reduce accidents, the negative effects of speeding and traffic noise in urban roads. In the scope of this study, horizontal calming measures, namely chicanes, which are not in use in Turkey yet, have been studied by using a driving simulator for the aim of controlling and reducing vehicular speeds. For this purpose, Akdeniz University campus was selected as the pilot case area and a number of different roads in the campus have been modeled in 3D. It was determined from the speed data that for divided four lane carriageways, chicane number 10 (K10) which has 3 m effective width and 45 entry and exit angles, for undivided two lane carriageways, chicane number 2 (K2) which has 2.7 m effective width and 60 entry and 30 exit angles, gave the best outcome from the driving tests in accordance with the characteristics of Turkish drivers. Furthermore, based on the findings, common driver errors are identified and a number of recommendations are made.
AtıfScopus6WoS5OpenAlex5TR Dizin5
İncele - MakaleYalnız künye2019Scopus SJRQ1Thermal Multisensor Fusion for Collaborative Robotics
Benli, Emrah; Spidalieri, Richard Lee; Motai, Yuichi
Collaborative robotic configurations for monitoring and tracking human targets have attracted interest in the fourth industrial revolution. The fusion of different types of sensors embedded in collaborative robotic systems achieves high-quality information and contributes to significantly improve robotic perception. However, current methods have not deeply explored the capabilities of thermal multisensory configurations in human-oriented tasks. In this paper, we propose thermal multisensor fusion (TMF) for collaborative robots to overcome the limitations of stand-alone robots. Thermal vision helps to utilize the heat signature of the human body for human-oriented tracking. An omnidirectional (O-D) infrared (IR) sensor provides a wide field of view (FOV) to detect human targets, and Stereo IR helps determine the distance of the human target in the oriented direction. The fusion of O-D IR and Stereo IR also creates a multisensor stereo for an additional determination of the distance to the target. The fusion of thermal and O-D sensors brings their limited prediction accuracy with their advantages. The maximum a posteriori method is used to predict the distance of the target with high accuracy by using the distance results of TMF stereo from multiple platforms according to the reliability of the sensors rather than its usage of visible-band-based tracking methods. The proposed method tracks the distance calculation of each sensor instead of target trajectory tracking as in visible-band methods. We proved that TMF increases the perception of robots by offering a wide FOV and provides precise target localization for collaborative robots.
AtıfScopus20WoS19OpenAlex21İncele - MakaleAçık Erişim2017Scopus SJRQ1Novel eugenol derivatives: Potent acetylcholinesterase and carbonic anhydrase inhibitors
Topal, Fevzi; Gulcin, Ilhami; Dastan, Arif; Guney, Murat
Eugenol was used as starting material to obtain some phenolic compounds. The synthesis of these phenolic compounds was performed in a two-step procedure. The structures of the formed products (novel eugenol derivatives 1–6) have been determined on the basis of NMR spectroscopy and other spectroscopic methods. The compounds were tested in terms of carbonic anhydrase (CA) inhibition potency. Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes, which catalyse the reaction between carbon dioxide (CO2) and water (H2O), to generate bicarbonate (HCO3−) and protons (H+). CO2, HCO3− and H+ are essential molecules and ions for many important physiologic processes occurring in all living organisms. Acetylcholinesterase (AChE, E.C.3.1.1.7) is found in high concentrations in the red blood cells and brain. Novel eugenol derivatives (1–6) were tested for the inhibition of two cytosolic CA isoforms I, and II (hCA I, and II) and AChE. These compounds demonstrated effective inhibitory profiles with Ki values in ranging of 113.48-738.69 nM against hCA I, 92.35-530.81 nM against hCA II, and 90.10-379.57 nM against AChE, respectively. On the other hand, acetazolamide clinically used as CA inhibitor, shoed Ki value of 594.11 nM against hCA I, and 120.68 nM against hCA II, respectively. Also, AChE was inhibited by tacrine as an AChE inhibitor at the 71.18 nM level.
AtıfScopus126WoS121OpenAlex133İncele - MakaleYalnız künye2016Scopus SJRQ1Subduction-related Late Carboniferous to Early Permian Magmatism in the Eastern Pontides, the Camlik and Casurluk plutons: Insights from geochemistry, whole-rock Sr–Nd and in situ zircon Lu–Hf isotopes, and U–Pb geochronology
Karsli, Orhan; Dokuz, Abdurrahman; Kandemir, Raif
Late Carboniferous to early Permian granitoid rocks represent a volumetrically minor component of the Eastern Pontide lithosphere, but they preserve useful information about the region's tectonomagmatic history. The Casurluk and Camlik plutons primarily consist of gabbro, gabbroic diorite, diorite, monzogabbro, monzodiorite and monzonite, which intrude early to middle Carboniferous granitic basement rocks in the region. In this study, we use in situ zircon U–Pb ages and Lu–Hf isotopic values, whole-rock Sr–Nd isotopic values, and mineral chemistry and geochemistry of these plutons to determine petrogenesis and crustal evolution; we also discuss geodynamic implications. LA–ICP-MS zircon U–Pb dating of magmatic zircons from the rocks suggests that the plutons were emplaced during the late Carboniferous to early Permian (302 Ma). The metaluminous and I-type intrusive rocks belong to the high-K calc-alkaline series. In addition, they are relatively enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs); they are depleted in heavy rare earth elements (HREEs) and high field strength elements (HFSEs), such as Nb and Ti. All of the samples have homogeneous initial ISr values (0.70675 to 0.70792) and low εNd (t) values (− 5.1 to − 3.3). Zircons from the rocks of both plutons have uniform negative to slightly positive εHf (t) values (− 3.5 to 1.4) and old Hf two-stage model ages (1323 to 1548 Ma), implying that they have the same source, as well as suggesting the involvement of old enriched lithospheric mantle materials during their magma genesis. These results, combined with the εHf (t) values and two-stage model ages, demonstrate that the primary magmas were derived from partial melting of old lithospheric mantle material metasomatized by subduction-related fluids. Considering other regional geological data from the Sakarya Zone where these plutons formed, we conclude that late Carboniferous to early Permian magmatism in the area involved the partial melting of a phlogopite- and spinel-bearing lherzolite under an extensional regime in a subduction-related setting. Such an extension event would have caused hot asthenospheric upwelling and was likely triggered by back-arc rifting during subduction of the Paleo-Tethyan oceanic slab. Thus, the magmas are likely subduction-related products, implying that southward subduction of Paleo-Tethys oceanic lithosphere in the region began during the late Carboniferous to early Permian.
AtıfScopus59WoS55OpenAlex65İncele - MakaleYalnız künye2018Scopus SJRQ1Transcription factors WRKY11 and WRKY17 are involved in abiotic stress responses in Arabidopsis
Ali, Muhammad Amjad; Azeem, Farrukh; Nawaz, Muhammad Amjad; Acet, Tuba; Abbas, Amjad; Imran, Qari Muhammad; Shah, Kausar Hussain; Rehman, Hafiz Mamoon; Chung, Gyuhwa; Yang, Seung Hwan
Plant WRKY transcription factors play a vital role in abiotic stress tolerance and regulation of plant defense responses. This study examined AtWRKY11 and AtWRKY17 expression under ABA, salt, and osmotic stress at different developmental stages in Arabidopsis. We used reverse transcriptase PCR, quantitative real-time PCR, and promoter:GUS lines to analyze expression. Both genes were upregulated in response to abiotic stress. Next, we applied the same stressors to seedlings of T-DNA insertion wrky11 and 17 knock-out mutants (single and double). Under stress, the mutants exhibited slower germination and compromised root growth compared with the wild type. In most cases, double-mutant seedlings were more affected than single mutants. These results suggest that wrky11 and wrky17 are not strictly limited to plant defense responses but are also involved in conferring stress tolerance.
AtıfScopus109OpenAlex119İncele - MakaleAçık Erişim2016Scopus SJRQ2Kinetic characterization of GES-22 β-lactamase harboring the M169L clinical mutation
Saral, Aysegul; Leonard, David A; Duzgun, Azer Ozad; Cicek, Aysegul Copur; June, Cynthia M; Sandalli, Cemal
The class A β-lactamase GES-22 has been identified in Acinetobacter baumannii isolates in Turkey, and subsequently shown to differ from GES-11 by a single substitution (M169L). Because M169 is part of the omega loop, a structure that is known to have major effects on substrate selectivity in class A β-lactamases, we expressed, purified and kinetically characterized this novel variant. Our results show that compared with GES-116×His, GES-226×His displays more efficient hydrolysis of penicillins, and aztreonam, but a loss of efficiency against ceftazidime. In addition, the M169L substitution confers on GES-22 more efficient hydrolysis of the mechanistic inhibitors clavulanic acid and sulbactam. These effects are highly similar to other mutations at the homologous position in other class A β-lactamases, suggesting that this methionine has a key structural role in aligning active site residues and in substrate selectivity across the class.
AtıfScopus5WoS4OpenAlex5İncele - MakaleAçık Erişim2016Scopus SJRQ2Determining the Effect of Seasonal Variation in Spruce (Picea orientalis L.) Wood Treated with Various Impregnations on Combustion Resistance
Yasar, Ş. Şadiye; Fidan, M. Said; Yaşar, Mehmet; Atar, Musa; Alkan, Elif
Prepared test specimens were surface treated and coated with synthetic and water-based outdoor varnishes after being chemically impregnated. The test specimens were left outdoors to determine the effects of impregnation and treatment on the wood during each of the four seasons. Caucasian spruce (Picea orientalis L.) test specimens were prepared and combustion analyses were performed. As a result of the combustion test, weight loss results, as compared with the control, were 89% lower in the spring specimens, 90% lower with impregnation, and 90% lower with the synthetic varnish coating. Furthermore, the O2 amount during combustion was found to be the highest in combustion with a flame source in the winter specimens (21%). The CO2 amount was the highest in combustion without a flame source for full-year specimens (20%). The CO amount was the highest in combustion without a flame source of full-year specimens (31,787 ppm), and the NO amount was the highest during glowing of full-year specimens (55 ppm). Final results showed impregnation with Tanalith-E and water-based varnish coating to be the most effective fire protective treatments.
AtıfScopus5WoS5OpenAlex3İncele - DüzeltmeYalnız künye2018Scopus SJRQ1Retraction notice to “Regional sustainable water and energy development projects: A case of Southeastern Anatolia Project (GAP) in Turkey” (Renew Sustain Energy Rev (2011) (16/2) (1146–1156)(S136403211100551X)(10.1016/j.rser.2011.11.015))
Akpinar, A.; Kaygusuz, K.
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. The authors have plagiarized part of a paper that had already appeared in Renewable Energy, Volume 39 (2012), Pages 17–23, DOI: 10.1016/j.renene.2011.08.006. Although the authors were contacted for a reaction, we were unsuccessful in obtaining a response. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper is not under consideration for publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.
AtıfOpenAlex1İncele - BildiriAçık Erişim2017Scopus SJRQ3Gold and silver content of plant Helichrysum arenarium, popularly known as the golden flower, growing in Gümüşhane, NE Turkey
Vural, A.
Geochemical and biogeochemical methods in mineral exploration have been widely used in recent years because of the depletion of known deposits and the need to explore buried deposits. The aim of this study was to investigate the gold and silver content of Helichrysum arenarium, popularly known as the golden flower, for possible exploration of precious ore deposits. For this purpose, plant samples of the respective plant parts (roots, stem-leaves and flowers) collected from Demirören village of Gümüşhane in the northeastern Turkey were analysed for gold and silver by using inductively coupled plasma mass spectrometry. Gold and silver contents of the plants was assessed on the basis of different statistical approaches. The results indicate that the plant has elevated levels of gold and silver concentrations, particularly in the case of gold. As a result, it was determined that the gold content of Helichrysum arenarium is remarkable and the gold accumulation capacity of the plant is high in the the stem-leaves, whereas the silver accumulation capacity of the plant is high in roots.
AtıfScopus12WoS8OpenAlex10İncele - MakaleYayıncıda açık erişim2019Scopus SJRQ1An experimental study on the compressive response of CFRP honeycombs with various cell configurations
Pehlivan, Levent; Baykasoğlu, Cengiz
The experimental investigation on the compressive response of carbon fiber reinforced polymer (CFRP) honeycombs with various cell configurations was carried out in the present work. The CFRP honeycomb specimens were manufactured by corrugation technique, in which the prepreg CFRP sheets were first corrugated into the certain shape using corrugated aluminum moulds under heat and pressure, and then the corrugated CFRP sheets were glued and stacked to construct honeycomb specimens. Twenty-seven groups of specimens were experimentally tested to examine the effects of cell geometry (i.e., square, circular, and hexagonal), cell wall thickness and height on the quasi-static out-of-plane crushing performance of the honeycombs. The square, circular, and hexagonal honeycomb specimen groups were designed to have almost the same weights. The results showed that the cell wall thickness is an significant parameters on the overal crushing response of the CFRP honeycombs while the out-of-plane compressive strenght of the honeycombs is generally independent of the height. It is observed that the hexagonal specimen groups have generally superior crushing performance in comparison with the square and circular counterparts due to their large double foil bonding surfaces. The experimental results also revealed that the crushing properties of the honeycomb structures with the core densities of 157–282 kg/m 3 could be increased more than two times with the appropriate selection of cell configurations.
AtıfScopus134WoS110OpenAlex122İncele - MakaleYalnız künye2019Scopus SJRQ1Adakite-like parental melt generation by partial fusion of juvenile lower crust, Sakarya Zone, NE Turkey: A far-field response to break-off of the southern Neotethyan oceanic lithosphere
Karsli, Orhan; Dokuz, Abdurrahman; Kandemir, Raif; Aydin, Faruk; Schmitt, Axel K.; Ersoy, E. Yalçın; Alyıldız, Cihangir
The timing of major tectonic events and the driving mechanisms for magma generation during Late Cenozoic convergence and collision between Arabia and Eurasia still remain unknown. The Sakarya Zone (SZ) in northern Turkey is a critical member of this collisional assemblage. In the easternmost part of the SZ, we have recognized a Late Miocene volcanic suite termed the Çağirankaya volcanics which displays characteristic post-collisional geochemical features. Here, we report a new data set of zircon U–Pb ages, whole-rock major and trace element, as well as Sr–Nd isotope analyses for dacite and andesite samples from the Çağirankaya volcanics. Zircon U–Pb ages for a selected dacitic sample average 5.16 ± 0.11 Ma (mean square of weighted deviates, MSWD = 0.45, n = 35), confirming a late Miocene age of this volcanic episode. The high-K calc-alkaline andesites and dacites exhibit an adakite-like geochemical signature, and are characterized by high Sr (424 to 552 ppm), Sr/Y ratios (31–43), and low Mg# (42 to 46) values, along with low Y (12–14 ppm) and heavy rare earth element (HREE) concentrations, that resemble those in adakites formed by partial melting of hot oceanic slab during subduction. Isotopic compositions are near bulk Earth (87Sr/86Sr(t) = 0.70482 to 0.70489, εNd(t) = +1.08 to +1.33), which rules out a solely asthenospheric origin. Elevated Nb/Ta (14 to 17) and K2O/Na2O (0.6–1.0) imply a juvenile mafic lower crustal source composed of ~20% garnet-bearing amphibolite. Geochemical modeling suggests that adakite-like parental melts were generated in the absence of subduction and without large-scale delamination of lower continental crust. Instead, our findings suggest that Late Miocene adakite-like volcanic rocks in the SZ formed in a post-collisional intra-continental setting, which experienced far-field extension after the subducted slab of the southern Neotethyan branch became detached in the collision zone. Asthenospheric upwelling and underplating of basaltic magma provided the heat for partial melting of lower crustal amphibolite, forming minor amounts of adakite-like melts in the SZ.
AtıfScopus47WoS43OpenAlex51İncele
