Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Kaygusuz, Abdullah(3)
- Akpinar, A.(2)
- Arslan, Mehmet(2)
- Duran, Celal(2)
- Kaygusuz, Kamil(2)
- Acar, Sami(1)
- Akal, Cuneyt(1)
- Akincioglu, Hulya(1)
- Alwasel, Saleh(1)
- Artan, Seyfettin(1)
- Aydin, K.(1)
- Aygun, Ali(1)
- Baltaci, Cemalettin(1)
- Bektas, Osman(1)
- Bektaş, Hakan(1)
- Bingol, Zeynebe(1)
- Bozbeyoglu, Pinar(1)
- Bulut, Volkan N.(1)
- Cakir, Mehmet Ali(1)
- Cakmak, Kader Cetin(1)
- Cay Cakir, Sumeyra(1)
- Cekic, Arif Burak(1)
- Chen, Long(1)
- Durmaz, Lokman(1)
- Eker, C.S.(1)
- Eyuboglu, Yener(1)
- Eyüboǧlu, Yener(1)
- Filiz, M.H.(1)
- Goren, Ahmet C.(1)
- Gulcin, Ilhami(1)
- Gundogdu, Ali(1)
- Göncüoglu, Mehmet Cemal(1)
- Gücer, Mehmet Ali(1)
- Hayaloglu, Pinar(1)
- Ilbeyli, Nurdane(1)
- Imamoglu, Mustafa(1)
- Karahan Caner, Suleyman(1)
- Karaman, Safa(1)
- Karaoglan, Fatih(1)
- Kavaz, Arzu(1)
Yayınlar
- MakaleYalnız künye2026Geochemical signature, detrital zircon U-Pb, and mica Ar-Ar age systematics from the Karadere Basement Unit of the İstanbul-Zonguldak Terrane (NW, Türkiye): evidence for an Avalonian-Cadomian active continental margin
Çimen, Okay; Gücer, Mehmet Ali; Göncüoglu, Mehmet Cemal; Akal, Cuneyt; Arslan, Mehmet; Simonetti, Antonio; Karaoglan, Fatih
The & Idot;stanbul-Zonguldak Terrane is located in northwest Anatolia and includes several outcrops with pre-Cambrian basement units. The Karadere Basement Unit represents the easternmost basement of this terrane and is composed of paragneiss, quartzite, and orthogneiss. The paragneiss and quartzite are cut by orthogneisses and disconformably overlain by Lower Ordovician to Middle Devonian cover units. Its pre-Cambrian to Palaeozoic tectonic evolution remains poorly understood, and therefore, this study reports whole-rock trace element signatures, detrital zircon U-Pb, and muscovite Ar-Ar age data for samples of paragneiss, quartzite, amphibolite, and orthogneiss. The whole-rock geochemical data indicate that the protoliths of the paragneiss and quartzite samples investigated here could have been derived from arc-related felsic magmatic units located in an active continental margin. The protoliths of amphibolites and orthogneiss samples are gabbro and granite, respectively, and their geochemical signatures are akin to those from continental arc igneous suites. The detrital zircon U-Pb data are characterized by predominantly Mesoproterozoic (84%) and lesser amount of Palaeoproterozoic and Neoproterozoic ages and suggest an early Tonian (youngest peak age of 915 +/- 18 Ma) maximum depositional age. Moreover, zircon U-Pb dating analyses from an orthogneiss sample yielded an age of 603 +/- 2 Ma, indicating the occurrence of mid-Ediacaran arc magmatism. This represents one of the oldest Ediacaran ages obtained from the metamagmatic basement rocks of the & Idot;stanbul-Zonguldak Terrane. Ar-Ar dating of muscovite from ortho- and paragneiss samples yielded ages of 533 +/- 25 Ma and 530 +/- 9 Ma, respectively, which are interpreted as early Cambrian cooling ages. Overall, the combined results reported here reveal that the Karadere Basement Unit is markedly different from NE African basement units but displays similarities to the basement rocks of both Avalonian and Amazonian terranes. It may have been formed and metamorphosed in an Avalonian-Cadomian active continental margin during the mid- to late Neoproterozoic and early Cambrian.
- MakaleYalnız künye2026Petrogenetic constraints and phase equilibria modelling on amphibole-bearing high-grade metamafic rocks from the Maku ophiolite (NW Iran): implications for metamorphism along the central Neo-Tethyan suture
Modjarrad, Monir; Uysal, Ibrahim; Yara, Irfan O. M. A.; Sen, Ahmet Dundar; Xin, Guangyao; Müller, Dirk
We present an integrated petrological, mineral-chemical, whole-rock geochemical, microstructural, and phase-equilibrium study of the West Maku metamafics (WMM), an ophiolite-related mafic unit in NW Iran. The WMM comprises garnet amphibolites and amphibole-bearing high-grade metamafic rocks containing almandine-rich garnet, tschermakite-ferro-tschermakite, andesine, epidote/zoisite, annite, muscovite-phengite, spinel, ilmenite, chlorite, quartz, and K-feldspar. Immobile element systematics indicate a tholeiitic, MORB-like basaltic protolith; LILE and crust-sensitive element enrichment likely reflect inherited crustal/sediment-derived components and metamorphic redistribution during subduction-accretion and/or m & eacute;lange assembly. P-T modelling defines four relative stages: M1, upper greenschist-facies metamorphism at ca. 6.4 kbar and 360 degrees C; M2, prograde heating to 8.0-8.4 kbar and 700-720 degrees C; M3, peak upper-amphibolite- to granulite-facies conditions at 9.0-9.8 kbar and up to 810 degrees C, with localized anatexis; and M4, retrogression at ca. 3.8 kbar and 520 degrees C. The clockwise path records the burial and heating of MORB-derived crust in a subduction-accretionary setting, followed by collision-related thermal relaxation/crustal thickening and subsequent uplift. Regional comparisons indicate thermally heterogeneous evolution along the central Neo-Tethyan suture across Armenia, SE T & uuml;rkiye, NE Iraq and NW Iran.
- Derleme MakaleYalnız künye2026Emerging thermal and non-thermal technologies addressing Salmonella contamination in low-moisture spices and herbs
Lian, Yi; Verma, Tushar; Chen, Long; Sun, Shengqian; Ozturk, Samet; Subbiah, Jeyamkondan; Liu, Shuxiang; Wei, Xinyao
Spices and herbs are vital flavoring agents in food. However, they are particularly vulnerable to microbial contamination primarily due to their open production environments and low water activity, which enhances microbial resistance to conventional pasteurization. In addition, traditional decontamination methods often struggle to balance microbial safety and product quality. This review aims to deliver valuable insights into innovative technologies designed for improving microbial safety and overall quality of spices and herbs while fostering advancements in the industry. This review comprehensively summarizes the principles, applications, and influencing factors of emerging thermal technologies (e.g., radio frequency heating, superheated steam, and vacuum steam) and non-thermal technologies (e.g., ethylene oxide, chlorine dioxide, cold plasma, and ionizing irradiation). Furthermore, it critically discusses the current limitations of these technologies and proposes strategies for future advancements. Novel decontamination technologies show promise in improving microbial safety and preserving the quality of spice and herb products. In particular, radio frequency and chlorine dioxide technologies emerge as promising options for spice decontamination due to their better ability to balance microbial control efficiency and quality retention. Further research should focus on optimizing parameters through models, developing combination technologies, and promoting pilot test verification to facilitate industrial application.
- MakaleYalnız künye2025Revealing the environmental influences of energy, transport, and pollution taxes on different transportation modes
Artan, Seyfettin; Pata, Ugur Korkut; Hayaloglu, Pinar; Cakir, Mehmet Ali; Recepoglu, Mursit; Cay Cakir, Sumeyra
The need for transportation is increasing with the effect of globalization in the developing economic system. The transportation sector, which is essential for economic development, may pose some threats to a sustainable environment. Although European countries have achieved various successes in reducing carbon emissions, they are struggling to reduce carbon dioxide (CO2) emissions from transportation. To overcome this difficulty, European countries are using various policy instruments such as environmental taxes. In this context, this study investigated the impact of disaggregated environmental taxes (pollution, energy, and transport), structural change, and institutional quality on transport-related carbon emissions (water, air, and road transport) in 24 European countries over the period 2008-2022. To this end, the study uses the novel half-panel jackknife estimation and the bias-corrected method of moments. The results indicate that there is no long-term relationship between environmental taxes and water transportation-related CO2 emissions. In contrast, structural changes and pollution taxes are effective in reducing road and air transport-related CO2 emissions. These results suggest that European countries should focus on reducing CO2 emissions through effective pollution taxes and encourage carbon taxes instead of energy and transport taxes, thereby supporting the European Green Deal's goal of becoming the first climate-neutral continent.
- MakaleYalnız künye2023Characterization of the Adsorption Mechanism of Cadmium(II) and Methylene Blue upon Corncobs Activated Carbon
Gundogdu, Ali; Bozbeyoglu, Pinar; Imamoglu, Mustafa; Baltaci, Cemalettin; Duran, Celal; Bulut, Volkan N.
A promising new activated carbon (AC) was produced from corncobs (CCs) by boric acid-based chemical activation to remove methylene blue (MB) as an organic pollutant and cadmium ions (Cd2+) as an inorganic pollutant from aqueous solutions. After the produced activated carbon (CCs-AC) was characterized, the adsorption mechanism of CCs-AC, which is one of the most interesting topics in the literature, was the primarily focus. The possible adsorption mechanisms of Cd2+ and MB on CCs-AC from aqueous solutions are discussed with respect to pH, thermodynamic values, and regeneration parameters. The results show that the adsorption of Cd2+ on CCs-AC was favorable at pH values higher than 4. In contrast, the adsorption process was almost pH-independent for MB. Variation of pH showed that the adsorption of Cd2+ on CCs-AC primarily occurs by electrostatic interaction. However, MB adsorption may also involve pi-pi dispersion forces and partial hydrogen bonding. The Cd2+ adsorbed on CCs-AC was quantitatively desorbed by HCl, whereas MB was not desorbed quantitatively by any solution. While a temperature increase has a positive effect on the adsorption of both methylene blue and Cd2+, the thermodynamic results show that MB adsorption is primarily chemisorption (Delta H of 24.28 kJ/mole), while Cd2+ adsorption is mostly physisorption (Delta H of 7.20 kJ/mole). Using Langmuir adsorption isotherms, the MB adsorption capacity of CCs-AC, which primarily has a microporous structure, was 0.88 mmol/g, while the Cd2+ adsorption capacity was 1.28 mmol/g.
- MakaleYalnız künye2022The Diagnostic Value of ischemia-modified albumin (IMA) and signal peptide-CUB-EGF domain-containing protein-1 (SCUBE-1) in an Experimental Model of Strangulated Mechanical Bowel Obstruction
Cekic, Arif Burak; Ozgen, Cekic Gonenc; Aygun, Ali; Pasli, Sinan; Ozer Yaman, Serap; Karahan Caner, Suleyman; Turedi, Suleyman; Acar, Sami; Tatli, Ozgur; Yulug, Esin
Background Mechanical bowel obstruction (MBO) is one of the principal pathologies requiring emergency surgery and a significant worldwide cause of morbidity. The identification of patients in whom bowel obstruction resolves spontaneously is important in terms of preventing unnecessary surgical interventions and future potential adhesions. The decision-making process is difficult in patients presenting without classic examination findings. Methods 36 female Sprague-Dawley rats randomly divided into six experimental groups. In Group 1, 3 and 5, laparotomy was performed, with blood and tissue specimens being collected after 1, 2 and 6 h, respectively. In Group 2, 4 and 6, the ileum segment was ligated following laparotomy, and blood and tissue specimens were collected after 1, 2 and 6 h, respectively. The ileum specimens were examined macroscopically, after which 1-cm sections were taken and examined in terms of histopathological changes. IMA and SCUBE-1 levels were determined for each group, and macro- and microscopic tissue examination findings were compared between the groups. Results Comparison within the groups exposed to waiting times of 1 h (groups 1 and 2), 2 h (groups 3 and 4) and 6 h (groups 5 and 6) revealed higher mean IMA and SCUBE-1 levels in rats undergoing ligation together with incision (groups 2, 4, and 6) compared to those undergoing laparotomy only (groups 1, 3, and 5). Correlation analysis was applied to determine the relationship between total scores obtained from histopathological examination and IMA and SCUBE-1 values. The analysis revealed strong, significant and positive correlation between histopathological examination scores and IMA (r=0.643, p=0.000) and SCUBE-1 (r=0.509, p=0.002) values. Conclusion The study findings showed that both IMA and SCUBE-1 values increased in a strangulated MBO model in rats. We think that IMA and SCUBE-1 values can be used as a markers of damage in the early period in strangulated MBO, and that the patient's surgery requirement can thus be determined in the early period.
- MakaleAçık Erişim2019Anticholinergic, antidiabetic and antioxidant activities of cinnamon (cinnamomum verum) bark extracts: polyphenol contents analysis by LC-MS/MS
Gulcin, Ilhami; Kaya, Ruya; Goren, Ahmet C.; Akincioglu, Hulya; Topal, Meryem; Bingol, Zeynebe; Cakmak, Kader Cetin; Sarikaya, Sevim B. Ozturk; Durmaz, Lokman; Alwasel, Saleh
Ethanolic (EEC) and aqueous (WEC) extracts of cinnamon (Cinnamomum verum) were evaluated for their antioxidant profiles by eight distinguished bioanalytical antioxidant methods. Their inhibitory effects were tested against some enzymes including acetylcholinesterase, butyrylcholinesterase, alpha-glycosidase and alpha-amylase, which linked to different diseases. Additionally, the antioxidant properties were determined and polyphenolic compositions of the both extracts were evaluated by LC-MS/MS analysis. According to the LC-MS/MS experiments, thirteen compounds were found in WEC and EEC. Also, p-hydroxybenzoic acid (321.1 mg/kg extract), p-coumaric acid (291.4 mg/kg extract), and pyrogallol (142.4 mg/kg extract) were found to be the most abundant ingredients in the WEC. On the other hand, pyrogallol (264.3 mg/kg extract), ferulic acid (224.7 mg/kg extract) and p-coumaric acid (170.2 mg/kg extract) were found as the most plentiful chemicals in the EEC. For the estimation of the antioxidant capacities of the both extracts (WEC and EEC), DPPH center dot and ABTS(center dot+) scavenging activities, as well as Fe3+-Fe2+, and Cu2+-Cu+ reducing assays were studied. The IC50 values of the WEC and EEC indicated that they were potent effective DPPH center dot (21. 25 and 15.71 mu g/mL) and ABTS(center dot+) (6.52 and 5.79 mu g/mL) scavengers, as well as AChE (221.33 and 110.26 mu g/mL), BChE (461.69 and 94.93 mu g/mL), alpha-glycosidase (206.86 and 220.00 mu g/mL) and alpha-amylase (189.86 and 200.86 mu g/mL) inhibitors. As a conclusion, both EEC and WEC had rich phenolic contents and demonstrated effective anticholinergic, antidiabetic and antioxidant effects.
- MakaleAçık Erişim2014Dynamic mechanical spectra of selected turkish honeys: Construction of predictive models for complex viscosity using two different nonlinear modeling techniques
Kayacier, Ahmed; Yüksel, Ferhat; Karaman, Safa
Dynamic oscillatory shear rheological characteristics of honey samples from different floral sources were evaluated using frequency sweep test and stress sweep test at three different temperatures (10, 15, and 20°C). All honey samples showed liquid-like behavior because the loss modulus was significantly greater than the elastic modulus. Pine honey showed the highest complex viscosity (86.33 Pa s at 10°C), while the lowest complex viscosity was observed in citrus honey (22.15 Pa s) at the same temperature. Temperature dependency of complex viscosity of honey samples was modeled by Arrhenius model and activation energy values of honeys ranged from 83.13 to 97.46 kJ/mol. An efficient predictive model for complex viscosity values of honeys was constructed using adaptive neuro fuzzy inference system that showed satisfactory prediction performance with high coefficient of determination (0.995) and low root mean square error (0.04) in the validation period compared to artificial neural networks.
- MakaleAçık Erişim2014The effect of cooking on total polyphenolic content and antioxidant activity of selected vegetables
Şengül, Memnune; Yildiz, Hilal; Kavaz, Arzu
The aim of this study to investigate the effect of different cooking methods (boiling, steaming, stir-frying, and microwaving) on the total polyphenolic content and total antioxidant activity of selected vegetables (beet, red cabbage, broccoli, white cabbage, black radish, kale, turnip, and red radish) from Turkey. A wide variation on total phenolic content was observed in raw vegetables, ranging from 44.94 ± 0.47 (beet, Beta vulgaris L. subsp. vulgaris) to 350.94 ± 5.18 (red radish, Raphanus sativus L.) μg gallic acid equivalent/mg of sample. Considering uncooked vegetables, the order of total antioxidant activity determined by β-carotene bleaching assay was beet > red cabbage > broccoli > white cabbage > black radish > kale > turnip > red radish. In DPPH• assay, kale had an exceptionally high antioxidant activity followed by red cabbage, broccoli, turnip, black radish, beet, white cabbage, and red radish.
- MakaleYalnız künye2013Organic geochemical characteristics and depositional environments of the eocene deposits in the eastern black sea region, NE Turkey
Eker, C.S.
Type of organic material, thermal maturity, depositional environment, and source rock potential of Eocene aged clastic rocks of the Eastern Black Sea Region were investigated. Based on total organic carbon values, clastic rocks range from weak-good source rock. Samples contain a mixture of Type I-Type III kerogen. Based on T max values, Eocene aged clastic rocks were thermally mature. Moretane/hopane ratio of samples <0.15, 22S/(22S + 22R) homohopane (C32), and 20S/(20S + 20R) sterane (C29) maturity parameters were equal or very close to equilibrium value of oil generation. The deposition environment was transitional marine environment and clastic rocks do not have the potential to form hydrocarbon.
- MakaleYalnız künye2012The total electricity energy production of the world, European Union, and Turkey: Projections and comparison
Akpinar, A.; Tavşan, F.; Kömürcü, Murat Ihsan; Filiz, M.H.; Kaygusuz, K.
This study aims to forecast the world's, European Union's (EU), and Turkey's electricity energy generation until 2030. For this purpose, the electricity energy sector of the world, EU, and Turkey was overviewed from past to present. The total electricity energy generation for the world, EU, and Turkey were then modelled by using historical energy generation data as years with regression analysis. Data from 1970 to 2004 for Turkey and data from 1980 to 2004 for the world and EU were used for the projections. Electricity energy productions have been forecasted up to year 2030. According to the results, it is determined that cubic (R2 = 0.997) and linear (R2 = 0.993) models for projection of the world's and EU's electricity energy generation, respectively, is fitness while the quadratic (R2 = 0.996) model fits for the projection of Turkey's total electricity energy generation and Turkey will have 0.995% of the world's electricity energy generation in 2030, while the EU will have 8.41% within the world's electricity energy generation in 2030 if the current trend continues.
- MakaleYalnız künye2012Performance and emission studies of castor bean (Ricinus Communis) oil biodiesel and its blends with diesel fuel
Özcanli, M.; Serin, H.; Saribiyik, O.Y.; Aydin, K.; Serin, S.
An experimental study was conducted to evaluate the use of various blends of castor (Ricinus Communis) oil methyl ester with diesel fuel. Performance and exhaust emissions of castor oil biodiesel with diesel fuel in a commercial compression ignition engine were presented in this study. Biodiesel produced from castor oil was blended with diesel fuel at the volumetric ratios of 5% (B5), 10% (B10), 25% (B25), 50% (B50), and 100% (B100). Fuel properties of castor oil methyl ester and its blends with diesel fuel were stated. The performance results showed that blends of castor oil methyl ester with diesel provided an increase on brake specific fuel consumption and a small decrease on brake power output. Compared with diesel fuel, diesel-castor oil methyl ester blends showed that while the carbon monoxide and carbon dioxide emissions became reduced; the oxides of nitrogen emissions observed higher than diesel fuel emission characteristics. Test results showed that B25 was determined as a suitable alternative fuel for diesel engines.
- MakaleYalnız künye2012Geochronological evidence and tectonic significance of Carboniferous magmatism in the southwest Trabzon area, eastern Pontides, Turkey
Kaygusuz, Abdullah; Arslan, Mehmet; Siebel, Wolfgang; Sipahi, Ferkan; Ilbeyli, Nurdane
The northern and southern zones of the eastern Pontides (northeast Turkey) contain numerous plutons of varying ages and compositions. Geochemical and isotopic results on two Hercynian granitoid bodies located in the northern zone of the eastern Pontides allow a proper reconstruction of their origin for the first time. The intrusive rocks comprise four distinct bodies, two of which we investigated in detail. Based on LA-ICP-MS U-Pb zircon dating, the Derinoba and Kayadibi granites have similar 206Pb/ 238U versus 207Pb/ 235U Concordia ages of 311.1 2.0 and 317.2 3.5 million years for the former and 303.8 1.5 million years for the latter. Aluminium saturation index values of both granites are between 0.95 and 1.35, indicating dominant peraluminous melt compositions. Both intrusions have high SiO 2 (74-77 wt.%) contents and show high-K calc-alkaline and I-to S-type characteristics. Primitive mantle-normalized element diagrams display enrichment in K, Rb, Th, and U, and depletion in Ba, Nb, Ta, Sr, P, and Ti. Chondrite-normalized rare earth element patterns are characterized by concave-upward shapes and pronounced negative Eu anomalies with L acn/Y bcn=4.6-9.7 and E ucn/Eu*=0.11-0.59 (Derinoba), and L acn/Y bcn=2.7-5.5 and E ucn/Eu*=0.31-0.37 (Kayadibi). These features imply crystal-melt fractionation of plagioclase and K-feldspar without significant involvement of garnet. The Derinoba samples have initial Nd values between-6.1 and-7.1 with Nd model ages and T DM between 1.56 and 2.15 thousand million years. The Kayadibi samples show higher initial Nd (I) values,-4.5 to-6.2, with Nd model ages between 1.50 and 1.72 thousand million years. This study demonstrates that the Sr isotope ratios generally display negative correlation with Nd isotopes; Sr isotope ratios were lowered in some samples by hydrothermal interaction or alteration. Isotopic and petrological data suggest that both granites were produced by the partial melting of early Palaeozoic lower crustal rocks, with minor contribution from the mantle. Collectively, these rocks represent a late stage of Hercynian magmatism in the eastern Pontides.
- BildiriYalnız künye2012Acetohydrazide derivative for selective separation and preconcentration of Cu(II) ions by coprecipitation method without using a carrier element
Ozdes, Duygu; Duran, Celal; Bektaş, Hakan; Tufekci, Mehmet; Soylak, Mustafa
A simple and rapid procedure based on the combination of carrier element free coprecipitation (CEFC) and flame atomic absorption spectrometric (FAAS) determinations has been developed for selective separation and preconcentration of Cu(II) ions in some environmental solid (Turkish and import coffee) and liquid (sea and stream waters) samples. In this method, acetohydrazide derivative was used as an organic coprecipitant without adding any carrier element for coprecipitation of Cu(II) ions. The preconcentration factor was found to be 50, the limit of detection (LOD) was 0.31 μgL -1, while the relative standard deviation (RSD) was found to be 1.6% for Cu(II) ions.
- MakaleYalnız künye2011Total electricity and hydroelectric energy generation in Turkey: Projection and comparison
Akpinar, A.; Kömürcu, M.I.; Özölçer, I.H.; Şenol, A.
The main goal of this study is to forecast total electricity and hydroelectricity energy generation using historical electricity energy production data in order to determine the future level of electricity and hydroelectricity energy generation in Turkey. For this purpose, Turkey's electricity energy sector was reviewed during the period of 1940-2005. The total electricity and hydroelectricity energy generation were then modelled using historical energy generation data as years with regression analysis. Additionally, the portion that hydroelectric energy generation of Turkey has within total electricity energy production and probable meeting capacity of Turkey's hydroelectric potential of its future total demand was determined. According to the results, it is deduced that hydropower energy will have portion of 13.6% within the total electricity energy generation in 2030. In addition, it is concluded that the whole of Turkey's technical and economical hydroelectric energy potential that is equal 129.9 billion kWh will be used in the year of 2102 if the current trend continues.
- MakaleYalnız künye2010Late Cretaceous high-K volcanism in the eastern Pontide orogenic belt: Implications for the geodynamic evolution of NE Turkey
Eyüboǧlu, Yener
High-K volcanics were produced in two different Late Cretaceous cycles during the infilling of back-arc basins of the eastern Pontides. The first cycle, represented by shoshonitic trachyandesites and associated pyroclastics, containing high K2O (2.74-4.81 wt-%) and NaK2O (3.60-5.51 wt-%), overlies a mid-Cretaceous ophiolitic-olistostromal melange formed during the rifting stage of a back-arc basin (Neotethys). 40Ar39Ar dating of biotite from trachyandesite at the base of the first cyle indicates that shoshonitic volcanism in the far south of the eastern Pontides started in the early Campanian. Volcanic rocks of this cycle are overlain by upper Campanian-Maastrichtian rudist-bearing reefal limestones. The second cycle of high-K volcanism is represented by analcime-bearing volcanic rocks erupted in a Neotethyan lagoonal environment. These volcanic rocks, intercalated with continental detritus, are characterized by high a2O (3.22-7.16 wt-%), now concentrated in secondary analcime crystals. Their K2O contents also range between 0.83 and 6.05 (wt-%). All of these units are disconformably overlain by Eocene turbidites with a basal conglomerate. Volcanic rocks belonging to both cycles show various enrichment degrees in LILE, HFSE, LREE, and HREE with respect to primitive mantle and chondrite [(La/Lu) cn=11.10-25.89]. Negative Nb, Ta, Zr, Hf, and Ti anomalies are typical of these subduction-related arc magmas. Geochemical similarities between the two volcanic cycles suggest that trachyandesites and analcime-bearing volcanics were derived from similar enriched mantle sources, and that they formed in the same geotectonic setting of a back-arc basin environment of the eastern Pontide magmatic arc during the Late Cretaceous. In addition, Nd-Sr and Pb isotope ratios of the investigated volcanic units indicate that their mantle melt sources were similar. The new geological, geochemical and isotopic data suggest that southward subduction of the Palaeotethyan oceanic crust can be separated into two main stages for the late Mesozoic Pontide orogenic belt. Early southward subduction ended by slab break-off during the mid-Cretaceous, resulting in upwelling and injection of asthenospheric mantle that caused the opening of the eastern Pontide back-arc basin (Neotethys). Resumption of southward subduction began with intense TH-CA bimodal volcanism in the northern front of the arc during the Turonian-Coniacian. The intensity of this Late Cretaceous magmatism in the north decreased towards the south, and a transition to monogenic calcalkaline-alkaline (CA-A) Campanian andesitic volcanism developed in the southern zone. Yet farther south, andesitic igneous activity graded into the Campanian-Maastrichtian shoshonitic and ultrapotassic volcanism in the Bayburt-Maden, Tokat, Amasya, and Gümüshaciköy areas. This zoning of the Late Cretaceous arc magmatism (TH-CA, CA-A and shoshonitic-ultrapotassic, from north to south) also supports the concept of southward subduction during late Mesozoic evolution of the eastern Mediterranean region.
- MakaleYalnız künye2007Mid-Cretaceous olistostromal ophiolitic mélange developed in the back-arc basin of the eastern Pontide magmatic arc, northeast Turkey
Eyuboglu, Yener; Bektas, Osman; Pul, Dilek
Geological and geochemical characteristics of the Mid-Cretaceous olistostromal ophiolitic mélange exposed in the southern part of the eastern Pontide magmatic arc indicates that it originally formed during the drifting stage of a back-arc basin (Neotethys). This view conflicts with the popular idea that this ophiolitic mélange represents a typical tectonic mélange or an accretionary prism developed in the fore-arc of the eastern Pontide magmatic arc by northward subduction of Neotethys or Paleotethys during the Cretaceous. This Mid-Cretaceous ophiolitic mélange is composed of the three distinct lithological facies that may reflect a strike-slip cycle - from transtensional to transpressive tectonic regimes - in the deep spreading troughs of pull-apart basins. The lower part of the mélange is represented by redeposited carbonate rocks that occur as an upward thinning and fining sequence. The middle level of the melange comprises basaltic pillow lavas, hyaloclastics, and intercalated pelagic sediments such as radiolarite, mudstone, and red pelagic limestone. The upper part of the mélange is represented by an olistolith-olistostromal facies that includes sandstone, siltstone, marl, and intervening olistoliths and olistostromes - mainly limestone, peridotite-gabbro, and metamorphic blocks derived from the continental shelf and a nearby peridotitic-metamorphic ridge. Trace-element and REE contents of the basaltic rocks belonging to the Mid-Cretaceous ophiolitic mélange show distinct geotectonic settings (IA, WP, MOR) with various enrichment and depletion trends with respect to MORB and chondrite. Moreover, this ophiolitic mélange is overlain by analcime-bearing Upper Cretaceous-Paleocene(?) shoshonitic basalts in the Bayburt-Maden area. These geological and geochemical data imply that mélange formed in the back-arc basin of the eastern Pontide magmatic are.
- MakaleYalnız künye2004Energy and sustainable development. Part II: Environmental impacts of energy use
Kaygusuz, Kamil; Kaygusuz, Abdullah
As a consequence of the fast-growing energy requirements and the increasing use of low-grade domestic fuels, air pollution has increased considerably in recent years in Turkey. Since the energy demand is projected to continue to increase rapidly in the future also, energy-supply strategies are required to control air-pollutant emissions in a cost-efficient way, taking into account the legal emission-control regulations that have been enforced. This article extensively concentrates on energy and environmental impacts in Turkey only. Energy utilization and its major environmental impacts are discussed from the standpoint of sustainable development, including anticipated patterns of future energy use and subsequent environmental issues. Several aspects relating to energy utilization, renewable energy, energy efficiency, environment, and sustainable development are examined from both current and future perspectives in the country. In this study, air-pollutant emissions due to power generation and their harmful effects on the environment are also estimated.
- MakaleYalnız künye2002Energy and sustainable development in Turkey. Part I: Energy utilization and sustainability
Kaygusuz, K; Kaygusuz, A
Turkey is an energy importing country; more than half of the energy requirement has been supplied by imports. Domestic oil and lignite reserves are limited, and lignites are characterized by high ash, sulfur and moisture content. In this regard, renewable energy resources appear to be one of the most efficient and effective solutions for sustainable energy development in Turkey. Turkey's geographical location has several advantages for extensive use of most of these renewable energy sources. Because of this and the fact that it has limited fossil fuel resources, a gradual shift from fossil fuels to renewables seems to be serious and the sole alternative for Turkey. This article presents a review of the present energy situation and sustainability, technical and economical potential of renewable energy sources, and future policies for the energy, sector in Turkey. Throughout this paper several problems relating to energy sources and sustainable development are discussed from both current and future perspectives.
- MakaleYalnız künye2002Geothermal energy: Power for a sustainable future
Kaygusuz, Kamil; Kaygusuz, Abdullah
This paper discusses the potential and utilization of geothermal energy in Turkey. Geothermal energy for electricity generation has been produced commercially since 1913, and for 4 decades on the scale of hundreds of MW both for electricity generation and direct use. Utilization has increased rapidly during the last 3 decades. In 2000, geothermal resources were identified in over 80 countries, and there are quantified records of geothermal utilization in 58 countries in the world. The worldwide use of geothermal energy amounts to 49 TWh/y of electricity and 53 TWh/y for direct use. On the other hand, Turkey is one of the countries with significant potential in geothermal energy. Resource assessments have been made many times by the Mineral Research and Exploration Directorate (MTA) of Turkey. The main uses of geothermal energy are mostly moderate and low temperature applications such as space heating and domestic hot water supply, greenhouse heating, industrial processes, heat pumps, and electricity generation. The data accumulated since 1962 show that the estimated geothermal power and direct use potential are about 4500 MWe and 31500 MWt, respectively. Present applications have shown that geothermal energy in Turkey and other countries is clean and much cheaper compared to the other fossil and renewable energy sources.