Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Alkan, Elif(6)
- Sipahi, Ferkan(6)
- Turan, Ibrahim(6)
- Akkan, Yaşar(5)
- Atar, Musa(5)
- Bostan, Sedat(5)
- Demir, Selim(5)
- Akaryali, Enver(4)
- Aksakal, Vecihi(4)
- Aliyazicioglu, Yuksel(4)
- Ates, Nagihan Gozde(4)
- Fidan, M. Said(4)
- Gergerli, Ruken(4)
- Kaygusuz, Abdullah(4)
- Okan, Tarhan(4)
- Tulgar, Serkan(4)
- Yilmaz, Fetullah(4)
- Akyüz, Ahmet Mutlu(3)
- Alwasel, Saleh H.(3)
- Arslan, Mehmet(3)
- Ashyralyev, A.(3)
- Aydınçakır, Emre(3)
- Aşık, Yusuf(3)
- Baltaci, Cemalettin(3)
- Bayraktar, Alemdar(3)
- Bayram, Bahri(3)
- Demir, S.(3)
- Dincel, Gungor Cagdas(3)
- Gocer, Hulya(3)
- Gökhan, Nezihe(3)
- Güllüpunar, Hasan(3)
- Gülçin, Ilhami(3)
- Günaydin, Murat(3)
- Kaplan, Abdullah(3)
- Karakan, Mehmet(3)
- Karakilic, Evvah(3)
- Küçük, Murat(3)
- Lukashov, A.(3)
- Merdan, Kurtuluş(3)
- Nazir, Bayram(3)
Yayınlar
- MakaleYalnız künye2016Antiproliferative and proapoptotic activity of Turkish propolis on human lung cancer cell line
Demir, Selim; Aliyazicioglu, Yuksel; Turan, Ibrahim; Misir, Sema; Mentese, Ahmet; Yaman, Serap Ozer; Akbulut, Kubra; Kilinc, Kagan; Deger, Orhan
Cancer is a heterogeneous disease, two of whose characteristic features are uncontrollable cell proliferation and insufficient apoptosis. Various studies have investigated the antiproliferative effects of propolis, a natural bee product, from different countries, and its cytotoxic effects have been attributed to its polyphenol contents. The purpose of this study was to show the cytotoxic effects, and possible mechanisms involved, of ethanolic extract of Turkish propolis (EEP) on the human lung cancer (A549) cell line. Cytotoxic activity of EEP on A549 cells was revealed using the MTT assay. Mechanisms involved in the cytotoxic action of EEP on A549 cells were then investigated in terms of apoptosis, mitochondrial membrane potential and cell cycle using flow cytometry, endoplasmic reticulum stress using RT-PCR, and caspase activity using luminometric analysis. EEP exhibited selective toxicity against A549 cells compared to normal fibroblast cells. We determined that EEP arrested the cell cycle of A549 cells at the G1 phase, induced endoplasmic reticulum stress, caspase activity, and apoptosis and reduced mitochondrial membrane potential. These results indicate that Turkish propolis is capable of reducing cancer cell proliferation and may have a promising role to play in the development of new anticancer drugs in the future.
- Derleme MakaleAçık Erişim2016Higher PUFA and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta- and redundancy analyses
Srednicka-Tober, Dominika; Baranski, Marcin; Seal, Chris J.; Sanderson, Roy; Benbrook, Charles; Steinshamn, Havard; Gromadzka-Ostrowska, Joanna; Rembialkowska, Ewa; Skwarlo-Sonta, Krystyna; Eyre, Mick
Demand for organic milk is partially driven by consumer perceptions that it is more nutritious. However, there is still considerable uncertainty over whether the use of organic production standards affects milk quality. Here we report results of meta-analyses based on 170 published studies comparing the nutrient content of organic and conventional bovine milk. There were no significant differences in total SFA and MUFA concentrations between organic and conventional milk. However, concentrations of total PUFA and n-3 PUFA were significantly higher in organic milk, by an estimated 7 (95% CI -1, 15)% and 56 (95% CI 38, 74) %, respectively. Concentrations of alpha-linolenic acid (ALA), very long-chain n-3 fatty acids (EPA + DPA + DHA) and conjugated linoleic acid were also significantly higher in organic milk, by an 69 (95% CI 53, 84) %, 57 (95% CI 27, 87)% and 41 ( 95% CI 14, 68) %, respectively. As there were no significant differences in total n-6 PUFA and linoleic acid (LA) concentrations, the n-6:n-3 and LA: ALA ratios were lower in organic milk, by an estimated 71 (95% CI -122, -20)% and 93 (95% CI -116, -70) %. It is concluded that organic bovine milk has a more desirable fatty acid composition than conventional milk. Meta-analyses also showed that organic milk has significantly higher alpha-tocopherol and Fe, but lower I and Se concentrations. Redundancy analysis of data from a large cross-European milk quality survey indicates that the higher grazing/conserved forage intakes in organic systems were the main reason for milk composition differences.
- Derleme MakaleAçık Erişim2016Composition differences between organic and conventional meat: a systematic literature review and meta-analysis
Srednicka-Tober, Dominika; Baranski, Marcin; Seal, Chris; Sanderson, Roy; Benbrook, Charles; Steinshamn, Havard; Gromadzka-Ostrowska, Joanna; Rembialkowska, Ewa; Skwarlo-Sonta, Krystyna; Eyre, Mick
Demand for organic meat is partially driven by consumer perceptions that organic foods are more nutritious than non-organic foods. However, there have been no systematic reviews comparing specifically the nutrient content of organic and conventionally produced meat. In this study, we report results of a meta-analysis based on sixty-seven published studies comparing the composition of organic and non-organic meat products. For many nutritionally relevant compounds (e.g. minerals, antioxidants and most individual fatty acids (FA)), the evidence base was too weak for meaningful meta-analyses. However, significant differences in FA profiles were detected when data from all livestock species were pooled. Concentrations of SFA and MUFA were similar or slightly lower, respectively, in organic compared with conventional meat. Larger differences were detected for total PUFA and n-3 PUFA, which were an estimated 23 (95% CI 11, 35)% and 47 (95% CI 10, 84)% higher in organic meat, respectively. However, for these and many other composition parameters, for which meta-analyses found significant differences, heterogeneity was high, and this could be explained by differences between animal species/meat types. Evidence from controlled experimental studies indicates that the high grazing/forage-based diets prescribed under organic farming standards may be the main reason for differences in FA profiles. Further studies are required to enable meta-analyses for a wider range of parameters (e.g. antioxidant, vitamin and mineral concentrations) and to improve both precision and consistency of results for FA profiles for all species. Potential impacts of composition differences on human health are discussed.
- MakaleYalnız künye2016A study to develop clinical decision rules for the use of radiography in wrist trauma: Karadeniz wrist rules
Karaca, Yunus; Turkmen, Suha; Cansu, Aysegul; Baki, Mehmet Emre; Eroglu, Oguz; Tatli, Ozgur; Gunaydin, Mucahit; Beyhun, Ercument; Gunduz, Abdulkadir; Eryigit, Umut
Introduction: The aim of this study was to evaluate patients presenting to the emergency department (ED) with wrist trauma using physical examination findings and functional tests and to identify findings with high sensitivity and specificity among the parameters assessed in patients with fracture in the wrist. The ultimate objective was thus to establish a reliable and widely usable clinical decision rule for determining the necessity of radiography in wrist trauma. Methods: This prospective, multicenter study was performed in 8 hospitals. The relation between radiologically determined fracture and clinical findings consisting of physical examination findings and functional tests was assessed in terms of whether or not these were markers of radiography requirement, with the aim of identifying predictive values for fracture. Results: A total of 603 eligible trauma patients presented to the participating EDs during the study period. Fracture was identified in 24.5% of patients (n= 148). The 4-way combination with the highest sensitivity was identified as axial compression and the positive distal radioulnar drawer test, and pain with radial deviation and dorsal flexion. Sensitivity at distal ulna palpation was added as a fifth parameter, and sensitivity and negative predictive value thus increased to 100%. Conclusion: With their 100% sensitivity and 100% negative predictive values, the Karadeniz wrist rules may represent a clinical decision rule that can be used in practice in EDs. If all 5 findings are negative, there is no indication for wrist radiography. (C) 2016 Elsevier Inc. All rights reserved.
- MakaleAçık Erişim2016Regulators of mitochondrial complex I activity: A review of literature and evaluation in postmortem prefrontal cortex from patients with bipolar disorder
Duong, Angela; Che, Yi; Ceylan, Deniz; Pinguelo, Arsene; Andreazza, Ana C.; Young, L. Trevor; Berk, Michael
Phenomenologically, bipolar disorder (BD) is characterized by biphasic increases and decreases in energy. As this is a state-related phenomenon, identifying regulators responsible for this phasic dysregulation has the potential to uncover key elements in the pathophysiology of BD. Given the evidence suggesting mitochondrial complex I dysfunction in BD, we aimed to identify the main regulators of complex I in BD by reviewing the literature and using the published microarray data to examine their gene expression profiles. We also validated protein expression levels of the main complex I regulators by immunohistochemistry. Upon reviewing the literature, we found PARK-7, STAT-3, SIRT-3 and IMP-2 play an important role in regulating complex I activity. Published microarray studies however revealed no significant direction of regulation of STAT-3, SIRT-3, and IMP-2, but a trend towards downregulation of PARK 7 was observed in BD. Immunocontent of DJ-1 (PARK-7-encoded protein) were not elevated in post mortem prefrontal cortex from patients with BD. We also found a trend towards upregulation of DJ-1 expression with age. Our results suggest that DJ-1 is not significantly altered in BD subjects, however further studies are needed to examine DJ-1 expression levels in a cohort of older patients with BD. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
- MakaleYalnız künye2016Preventing Suture Extrusion and Recurrence in Mustarde and Furnas Otoplasties by Using Laterally Based Postauricular Dermal Flap, Long-Term Results
Basat, Salih Onur; Ceran, Fatih; Askeroglu, Ufuk; Aksan, Tolga; Orman, Cagdas; Yazar, Memet; Uscetin, Ilker; Akan, Mithat; Bozkurt, Mehmet
Background:Prominent ear deformity (PD) is an unacceptable condition of pinna that affects 5% of the population and is associated with emotional stress, behavioral disturbances, and social restrictions in relationships. Conchal hypertrphy, inadequate formation of antihelical fold, earlobe placement ahead than it should be, or various combinations of these changes are main characteristics of PD. Many surgical techniques have been described for the PD.The authors' aim was to present laterally based postauricular dermal flap combination with cartilage-sparing methods and effectiveness of this technique in suture extrusion prevention and reducing the rate of recurrence with long-term results.Methods:Forty-one patients had bilateral and 6 patients had unilateral PD, a total of 47 patients with a mean age of 14.48 were operated by using this combined procedure. A laterally based supraperichondrial dermal flap was prepared from a deepithelized elliptical postauricular incision. Mustarde and Furnas suture techniques were used solely for PD correction. The dissected laterally based dermal flap was fixed to the mastoid bone with sutures in stretched position after reshaping the auricular cartilage with sutures.Results:The average helix-mastoid distance was (mm) 16.282.36, concha-mastoid angle was 25.71 +/- 0.96 degrees on 12-month measurements. The helix-mastoid distance showed an increase of 1 to 3mm, in the concha-mastoid angle measurements of 1 degrees to 2 degrees. Statistically significant changes were observed between the average preoperative, postoperative 1. month, postoperative 12. month helix-mastoid distances (mm), and month concha-mastoid angle (degrees) measurements (P=0.0001).Conclusions:The laterally based postauricular dermal flap technique is an effective method to prevent suture extrusion and recurrence which are the most important complications of otoplasty procedure and easy to apply.
- MakaleAçık Erişim2016Acetylcholinesterase and carbonic anhydrase isoenzymes I and II inhibition profiles of taxifolin
Gocer, Hulya; Topal, Fevzi; Topal, Meryem; Küçük, Murat; Teke, Dilek; Gülçin, Ilhami; Alwasel, Saleh H.; Supuran, Claudiu T.
Taxifolin, also known as dihydroquercetin, is a flavonoid commonly found in plants. Carbonic anhydrase (CA, EC 4.2.1.1) plays an important role in many critical physiological events including carbon dioxide (CO2)/bicarbonate (HCO3-) respiration and pH regulation. There are 16 known CA isoforms in humans, of which human hCA isoenzymes I and II (hCA I and II) are ubiquitous cytosolic isoforms. In this study, the inhibition properties of taxifolin against the slow cytosolic isoenzyme hCA I, and the ubiquitous and dominant rapid cytosolic isoenzyme hCA II were studied. Taxifolin, as a naturally bioactive flavonoid, has a K-i of 29.2nM against hCA I, and 24.2nM against hCA II. For acetylcholinesterase enzyme (AChE) inhibition, K-i parameter of taxifolin was determined to be 16.7nM. These results clearly show that taxifolin inhibited both CA isoenzymes and AChE at the nM levels.
- MakaleYalnız künye2016Mean platelet volume is related with ischemic stroke in patients with sinus rhythm
Özkan, Bugra; Arik, Osman Z.; Gözükara, Mehmet Y.; Sahin, Durmus Y.; Topal, Salih; Uysal, Onur K.; Elbasan, Zafer; Epçeliden, Tuncay; Çayil, Murat; Gür, Mustafa
Stroke is the leading cause of disability worldwide. It is known that atrial fibrillation and left atrial enlargement contribute ischemic stroke, and mean platelet volume (MPV) increases in patients with ischemic stroke and atrial fibrillation. We aimed to determine whether higher MPV is associated with ischemic stroke in patients with sinus rhythm. We evaluated 74 patients in sinus rhythm and with ischemic stroke (Group 1) and 90 age-matched and sex-matched healthy individuals as control group (Group 2). After physical and echocardiographic examination, 24-48 h Holter monitoring and complete blood counts were studied. There were no statistically significant differences in age, sex rates, and comorbidities between groups. Left atrial diameter was higher in Group 1 than Group 2 (P=0.001), but both were in normal range. MPV was significantly higher in Group 1 (P<0.001) and was an independent determinant [odds ratio (OR): 1.840; P<0.001; 95% confidence interval (CI) 1.330-2.545] of ischemic stroke with left atrial (OR: 1.138; P=0.006; 95% CI 1.037-1.248). In conclusion, higher MPV is associated with acute ischemic stroke in patients with sinus rhythm and without heart failure or left atrial enlargement. MPV and left atrial diameter are independent predictors of ischemic stroke in this patient population. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.
- MakaleYayıncıda açık erişim2016Comparison of Effects of Separate and Combined Sugammadex and Lipid Emulsion Administration on Hemodynamic Parameters and Survival in a Rat Model of Verapamil Toxicity
Tulgar, Serkan; Kose, Halil Cihan; Piroglu, Isilay Demir; Karakilic, Evvah; Ates, Nagihan Gozde; Demir, Ahmet; Gergerli, Ruken; Guven, Selin; Piroglu, Mustafa Devrim
Background: Toxicity of calcium channel blockers leads to high patient mortality and there is no effective antidote. The benefit of using 20% lipid emulsion and sugammadex has been reported. The present study measured the effect of sugammadex and 20% lipid emulsion on hemodynamics and survival in a rat model of verapamil toxicity. Material/Methods: In this single-blinded randomized control study, rats were separated into 4 groups of 7 rats each: Sugammadex (S), Sugammadex plus 20% lipid emulsion (SL), 20% lipid emulsion (L), and control (C). Heart rates and mean arterial pressures were monitored and noted each minute until death. Results: Average time to death was 21.0 +/- 9.57 minutes for group C, 35.57 +/- 10.61 minutes for group S, 37.14 +/- 16.6 minutes for group L and 49.86 +/- 27.56 minutes for group SL. Time to death was significantly longer in other groups than in the control group (p<0.05). Conclusions: Verapamil overdose is has a comparatively high mortality rate and there is no effective antidote. Treatment generally involves gastric decontamination and symptomatic treatment to counteract the drug's negative effects. In animal studies sugammadex and lipid emulsion had a positive effect on survival in patients with calcium channel blocker toxicity. Sugammadex and intralipid increased survival in a rat model of verapamil toxicity. The combination of both drugs may decrease cardiotoxicity. Sugammadex alone or combined with 20% lipid emulsion reduce the need for inotropic agents. The mechanism requires clarification with larger studies.
- MakaleAçık Erişim2016A novel modified PAIR technique using a trocar catheter for percutaneous treatment of liver hydatid cysts: a six-year experience
Nayman, Alaaddin; Guler, Ibrahim; Keskin, Suat; Erdem, Tuba Berra; Borazan, Hale; Kucukapan, Ahmet; Ozbiner, Huseyin; Batur, Abdussamed; Ertekin, Ersen; Feyzioglu, Bahadir
PURPOSE We aimed to demonstrate the success and reliability of a novel puncture, aspiration, injection, and reaspiration (PAIR) technique in liver hydatid cysts. METHODS Percutaneous treatment with ultrasonographic guidance was performed in 493 hepatic hydatid cysts in 374 patients. Patients were treated with a new PAIR technique by single puncture method using a 6F trocar catheter. The results of this novel technique were evaluated with regards to efficacy and safety of the procedure and complication rates. RESULTS Out of 493 cysts, 317 were Gharbi type I (WHO CE 1) and 176 were Gharbi type II (WHO CE 3A). Of all cysts, 13 were referred to surgery because of cystobiliary fistulization. Recurrence was observed in 11 cysts one month later. Therefore, the success rate of the PAIR technique was 97.7% (469/480). Minor complications (fever, urticaria-like reactions, biliary fistula) were seen in 44 treated patients (12%, 44/374); the only major complication was reversible anaphylactic shock which was observed in two patients (0.5%, 2/374). CONCLUSION This novel modified PAIR technique may be superior to catheterization by Seldinger technique due to its efficiency, easier application, lower severe complication rate, and lower cost. Further comparative studies are required to confirm our observations.
- MakaleYalnız künye2016MODIFIED KDIGO FOR PREDICTING MORTALITY IN ICU PATIENTS RECEIVING CONTINUOUS RENAL REPLACEMENT THERAPY FOR ACUTE RENAL FAILURE: KDIGO-URINARY OUTPUT VS. KDIGO-SERUM CREATININE LEVEL
Tulgar, Serkan; Cakiroglu, Basri; Cevik, Banu Eler; Karakilic, Evvah; Ates, Nagihan Gozde; Gergerli, Ruken; Ozdemir, Erman
Introduction: Acute Renal Injury (ARI) is a constant problem for patients in intensive care and Continuous Renal Replacement Therapy (CRRT) is an ever-more important part of acute renal injury (ARI) treatment. Various criteria have been used for the diagnosis and classification of acute renal failure, including RIFLE (Risk-Injury-Failure-Loss-End stage), AKIN (Acute Kidney Injury Network) and most recently KDIGO (Kidney Disease: Improving Global Outcomes). Many studies have only evaluated urinary output or serum creatinine when categorizing ARI. Our aim was to determine the predictors of mortality in intensive care patients treated with CRRT and to compare mortality with ARI level as determined by KDIGO-Serum Creatinine (KDIGO-SCr) and KDIGO-urinary output (KDIGO-UO) Materials and methods: This retrospective study was performed on intensive care patients receiving CRRT at our institute between January 2010-December 2011. Patient files were reviewed and demographic data, hospitalization time, laboratory findings, CRRT commencement and ARI levels were noted. Results: Seventy patients were included in the study. Mortality was found to be associated with patients' age, Glascow Coma Scale (GCS) score, Acute Physiology and Chronic Health Evaluation (APACHE) II score and adjusted predicted death rate. (p<0,01). Receiver Operating Curve (ROC) area under the curve was statistically significant for determination of mortality using KDIGO-SCR (p<0.01) although the same was not true for KDIGO-UO (p>0.05). Conclusions: We believe that RIFLE, AKIN, KDIGO criteria are each good predictors of mortality. In the case of KDIGO criteria, based solely on serum creatinine or urinary output, KDIGO-SCr was found to be a better predictor of mortality when compared to KDIGO-UO.
- MakaleAçık Erişim2016Complex subvolcanic magma plumbing system of an alkali basaltic maar-diatreme volcano (Elie Ness, Fife, Scotland)
Gernon, T. M.; Upton, B. G. J.; Ugra, R.; Yücel, C.; Taylor, R. N.; Elliott, H.
Alkali basaltic diatremes such as Elie Ness (Fife, Scotland) expose a range of volcanic lithofacies that points to a complex, multi -stage emplacement history. Here, basanites contain phenocrysts including pyrope garnet and sub-calcic augites from depths of similar to 60 km. Volcanic rocks from all units, pyroclastic and hypabyssal, are characterised by rare earth element (REE) patterns that show continuous enrichment from heavy REE (HREE) to light REE (LREE), and high Zr/Y that are consistent with retention of garnet in the mantle source during melting of peridotite in a garnet lherzolite fades. Erupted garnets are euhedral and unresorbed, signifying rapid ascent through the lithosphere. The magmas also transported abundant pyroxenitic clasts, cognate with the basanite host, from shallower depths (similar to 35-40 km). These clasts exhibit wide variation in texture, mode and mineralogy, consistent with growth from a range of compositionally diverse melts. Further, clinopyroxene phenocrysts from both the hypabyssal and pyroclastic units exhibit a very wide compositional range, indicative of polybaric fractionation and magma mixing. This is attributed to stalling of earlier magmas in the lower crust principally from similar to 22 to 28 km as indicated by pyroxene thermobarometry. Many clinopyroxenes display chemical zoning profiles, occasionally with mantles and rims of higher magnesium number (Mg#) suggesting the magmas were mobilised by juvenile basanite magma. The tuffs also contain alkali feldspar megacrysts together with Feclinopyroxene, zircon and related salic xenoliths, of the 'anorthoclasite suite' - inferred to have crystallised at upper mantle to lower crustal depths from salic magma in advance of the mafic host magmas. Despite evidence for entrainment of heterogeneous crystal mushes, the rapidly ascending melts experienced negligible crustal contamination. The complex association of phenocrysts, megacrysts and autoliths at Elie Ness indicates thorough mixing in a dynamic system immediately prior to explosive diatreme-forming eruptions. (C) 2016 Elsevier B.V. All rights reserved.
- MakaleYalnız künye2016Do early procalcitonine levels aid in predicting mortality in burn patients?
Piroglu, Isilay Demir; Tulgar, Serkan; Piroglu, Mustafa Devrim; Thomas, David Terence; Karakilic, Evvah; Gergerli, Ruken; Ates, Nagihan Gozde; Demir, Ahmet
Aim: Burn patients in intensive care units (ICU) are at high risk of mortality. Our aim in this stuy is to evaluate the use of first 48 hour procalcitonin level (PCT), C-reactive protein (CRP) and APACHE II score for the prediction of mortality in burn patients admitted to ICU. Material and method: Files of patients with burns admitted to a tertiary centre's burn unit were retrospectively analysed and those with procalcitonin and C-reactive protein level measurements and APACHE II scores within first 48 hours of admittance were included in this study. Patients with comorbidities that would effect PCT and CRP levels such as chronic renal or liver failure were excluded from the study. Patients PCT, CRP and APACHE II scores were compared with the outcome of patients. Results: Seventy patients were included in this study. While CRP levels were lower in patients that were deceased, PCT levels were significantly higher in these patients. In patients with APACHE II score > 20 and PCT > 2 ng/ml, mortality was statistically very significantly higher compared with other patients. Logistical regression analysis showed that high PCT levels and APACHE II scores were important at predicting mortality in these patients. Conclusion: High PCT levels within 48 hours of burns is a predictor of mortality in these patients. Additional studies are required to correctly determine the cut-off value. A modified scoring system including APACHE II and PCT may be useful for better predicting mortality, although larger multi-centered studies are required.
- MakaleYalnız künye2016Permo-Carboniferous granitoids with Jurassic high temperature metamorphism in Central Pontides, Northern Turkey
Gücer, Mehmet Ali; Arslan, Mehmet; Sherlock, Sarah; Heaman, Larry M.
In the northern part of the Central Pontides (N Turkey) there are different metamorphic rocks exposed, notably the Devrekani metamorphic rocks. Here, upper amphibolite-lower granulite facies metamorphic rocks contain predominantly paragneiss, orthogneiss and metacarbonate, and to a lesser extent, amphibolite and quartzite, with cross-cutting aplite, pegmatite and granite veins. This is the first report of these rocks and includes new data on the petrochemistry, geochronology and metamorphic evolution of the Devrekani orthogneisses from the Central Pontides. The orthogneisses show five different mineral parageneses with the characteristic mineral assemblage quartz + K-feldspar + plagioclase + biotite +/- hornblende +/- opaque (+/- ilmenite and +/- magnetite), and accessory minerals (zircon, sphene and apatite). These metamorphic rocks exhibit generally granoblastic, lepidogranoblastic and nematolepidogranoblastic with locally migmatitic and relic micrographic textures. They have well-developed centimeter-spaced gneissic banding and display gneissose structure with symmetric, asymmetric and irregular folds. The petrographic features, mineralogical assemblages and weak migmatization reflect high temperature conditions. Thermometric calculations in the orthogneisses indicate metamorphic temperatures reached 744 +/- 33 A degrees C. Field relations, petrography and petrochemistry suggest that the orthogneisses have predominantly granodioritic and some granitic protoliths, that show features of I-type, medium to high-potassic calc-alkaline volcanic arc granitoids. The orthogneisses have high contents of LILEs and low contents of HFSEs with negative Nb and Ti anomalies, which are typical of subduction-related magmas. The orthogneisses also show significant LREE enrichment relative to HREE with negative Eu anomalies (Eu-N/Eu* = 0.33-1.07) with La-N/Lu-N = 6.98-20.47 values. Based on U-Pb zircon dating data, the protoliths are related to Permo-Carboniferous (316-252 Ma) magmatism. It is likely that peak metamorphism took place during the Jurassic as reflected by the U-Pb zircon ages (199-158 Ma) and also 40Ar/39Ar from hornblende/biotite (163-152 Ma). The four biotite 40Ar/39Ar average ages from the rock samples are ca. 156 Ma, suggesting that the metamorphic rocks cooled to 350-400 A degrees C at ca. 156 Ma. Conclusively, the Devrekani metamorphic rocks can be ascribed as products of Permo-Carboniferous continental arc magmatism overprinted by Jurassic metamorphism in the northern Central Pontides.
- MakaleYalnız künye2016Cenozoic forearc gabbros from the northern zone of the Eastern Pontides Orogenic Belt, NE Turkey: Implications for slab window magmatism and convergent margin tectonics
Eyuboglu, Yener; Dudas, Francis O.; Santosh, M.; Zhu, Di-Cheng; Yi, Keewook; Chatterjee, Nilanjan; Jeong, Youn-Joong; Akaryali, Enver; Liu, Ze
The Eastern Pontides Orogenic Belt represents one of the best examples of fossil convergent margins in the eastern Mediterranean region. However, the origin and geodynamic setting of the late Mesozoic-Cenozoic magmatism in this belt remain controversial due to lack of systematic geological, geochemical and chronological data. The general consensus is that the late Mesozoic-Cenozoic igneous activity is related to northward subduction of oceanic lithosphere in the late Mesozoic and following collision between Tauride and Pontide blocks in the early Cenozoic Here we present a comprehensive study focusing on the origin and geodynamic setting of gabbro bodies exposed along a narrow zone, parallel to the southeastern coast of the eastern Black Sea basin, in the Northern Zone of the Eastern Pontides Orogenic Belt. The studied gabbro bodies are hosted within late Cretaceous basaltic, andesitic, and dacitic volcanics including pyroclastic rocks and interbedded sedimentary rocks. The gabbro bodies range in size from 0.1 km(2) to 1.5 km(2), and outcrop patterns vary from round or elliptical to markedly elongate with sharp and discordant contact with the host rocks. Their mineral assemblage includes mainly clinopyroxene, plagioclase, minor olivine, amphibole, magnetite and rarely orthopyroxene, biotite, zircon and titanite. The occurrence of sutured grain boundaries on clinopyroxene and plagioclase, and the presence of reverse compositional zoning in clinopyroxene and olivine suggest mixing between magmas of contrasting compositions during mineral growth. Thermobarometric computations indicate that the temperature at the beginning of crystallization was similar to 1250 degrees C and crystallization was polybaric Zircon and titanite U-Pb ages indicate that these small intrusions were emplaced into crustal rocks of the Eastern Pontides Orogenic Belt during Lutetian (45 +/- 2 Ma). The depletion of HFSE is consistent with the involvement of an arc-related source in the petrogenesis of these rocks, and low to moderate enrichment Ce, Rb, Ba, K, Pb, Sr and Th suggests that involvement of subducted oceanic sediment was modest. The low Th content and low Th/Yb indicate that the role of sediment addition was nevertheless limited. The Nd, Sr and Pb isotopic data are consistent with the interpretation that the dominant source component in these gabbros is a depleted, peridotitic mantle, and that crustal contamination is relatively unimportant. We suggest that mafic magmas that produced the gabbroic intrusions were derived from melting of a depleted mantle source under the forearc region of the Eastern Pontides Orogenic Belt during southward subduction of two oceanic plates separated by a mid-ocean ridge, leading to the formation of a slab window. We also infer fractional crystallization and assimilation during both magma storage in the crust-mantle transition zone and transfer into the overlying arc crust. (C) 2015 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.