Gümüşhane ÜniversitesiGümüşhane ÜniversitesiAçık Erişim Arşivi · RDL Open

Sürdürülebilir Kalkınma Amaçları

Yazarlar

Yayınlar

Yeniden eskiyeEskiden yeniye
  • MakaleYalnız künye2011
    The effects of some organic and chemical fertilizer applications on yield, morphology, quality and mineral content of common vetch (Vicia sativa L.)

    Yolcu, Halil

    A field experiment was conducted to evaluate the effects of some organic and chemical fertilizers on morphological, yield and quality properties and mineral contents of common vetch (Vicia sativa L.) between 2007 and 2008 in Gümüşhane, Turkey. Treatments were control (no fertilizer), liquid manure (LM = 51-52 L ha -1N), chemical fertilizer (CF = 30 kg N ha -1+ 80-100 kg P 2O 5ha -1), three leonardite doses (L 1= 2.8; L 2= 5.6 and L 3= 8.4 kg N ha -1), three zeolite doses (Z 1= 0.4; Z 2= 0.8 and Z 3= 1.2 N kg ha -1) and three solid cattle manure doses (SM 1= 34-35 kg N ha -1, SM 2= 68-70 kg N ha -1, SM 3= 102-105 kg N ha -1). Dry hay yield (DHY), leaf weight, stem weight, plant height, leaf number, crude protein content (CP), crude protein yield (CPY), acid detergent fiber (ADF), neutral detergent fiber (NDF), Ca, Fe, K, Mg, B, Cu, Mn, Na, Ni, P, Pb, S and Zn contents were determined. Organic and chemical fertilizer applications had significant effect (P<0.01) on DHY, leaf weight, stem weight, CP, CPY and mineral contents except leaf number, ADF and NDF in the both years. The plant height were significantly (P<0.05) affected by the treatments in the first year. The SM 2application in the first year and control and LM applications in the second year resulted to obtain improved yield components and crude protein yield. Z 2and Z 3applications also loomed large in terms of mineral contents.

    İncele
  • BildiriAçık Erişim2011
    The love of money is the root of all evil: Pay satisfaction and cpi as moderators

    Tang, Thomas Li-Ping; Sutarso, Toto; Ansari, Mahfooz A.; Lim, Vivien Kim Geok; Teo, Thompson Sian Hin; Arias-Galicia, Fernando; Garber, Ilya; Vlerick, Peter; Liang, Jian; Akande, Adebowale

    By incorporating pay satisfaction at Level 1 and Corruption Perceptions Index (CPI) at Level 2, we investigated the relationship between the love of money and self-reported corrupt intent among 6,382 managers in 31 geopolitical entities across six continents. Our significant cross-level three-way interaction effect showed that for managers with high pay satisfaction, the intensity (slope) of the love of money to corrupt intent relationship was almost identical in high or low CPI entities but the former had the lowest magnitude of corrupt intent, whereas the latter had the highest. For those with low pay satisfaction, the slope was the steepest in high CPI entities, but was flat in the low CPI entities and the difference between the two was significant.

    • SDG 16 · Barış, Adalet ve Güçlü Kurumlar
    İncele
  • MakaleYalnız künye2011
    Aromatisation in adducts of a-terpinene: Influence of hindered internal Rotations

    Kaya, Afşin Ahmet; Şengül, Mehmet Emin; Menzek, Abdullah; Kayaardi, Ibrahim; Karakuş, Murat; Şahin, Ertan

    Each adduct of α-terpinene with p-quinone and 1,4-naphthoquinone in Ac2O/Et3N at 180 °C gives two aromatic products, one of which had a distinctive smell formed by the loss of an ethylene group. Here, we report the crystal structure of (1RS, 4RS)-1-isopropyl-4-methyl-1,4-dihydro- 1,4-ethanoanthracene-9,10-diyl diacetate. It is crystallised in an orthorhombic space group, Pbca, with cell dimensions a = 10.2899(7), b = 19.7804(9), c = 19.7519(8) Å and Z = 8. According to its NMR and X-ray diffraction data, the isopropyl and acetate groups slowly rotate.

    İncele
  • MakaleAçık Erişim2011
    The effect of material properties on the seismic performance of Arch Dams

    Sevim, B.

    The paper investigates the effect of material properties on the seismic performance of arch dam-reservoir-foundation interaction systems based on the Lagrangian approach using demand-capacity ratios. Type-5 arch dam is selected as a numerical application. The linear time history analyses of the arch dam-reservoir-foundation interaction system are carried out for different material properties. The foundation is taken into account as massless; behaviour of the reservoir is assumed to be linearly elastic, inviscid and irrotational. The north-south component of the Erzincan earthquake in 1992 is chosen as a ground motion. Dynamic equations of motions obtained from 3-D finite element modelling of the coupled system are solved by using the Newmark integration algorithm. The damage levels of the coupled system for the different material properties are demonstrated by using demand-capacity ratios and cumulative inelastic durations. The time histories and maximum values of the displacements and principal stresses, and performance curves, are obtained from linear analyses. It is clearly seen from the study that the different material properties affect the seismic behaviour of the dam.

    İncele
  • MakaleYalnız künye2011
    Restructuring of Turkey's electricity market and the share of hydropower energy: The case of the Eastern Black Sea Basin

    Uzlu, Ergun; Akpinar, Adem; Kömürcü, Murat Ihsan

    This paper presents the historical development of Turkey's electricity power sector, the efforts for introducing competition in the power industry in Turkey, and the concerns regarding restructuring in Turkey. The contribution of the hydropower energy potential in Turkey to the reconstruction of the electricity structure in Turkey is also investigated. Then, among the 25 hydrological basins in Turkey, the Eastern Black Sea Basin located in the northeast of Turkey, which has great advantages from the view point of small hydropower potential or hydropower potential without storage, is chosen as the case study to carry out some investigations concerning its potential and to analyze the contribution of the private sector (the corporate body) in regard to the development of hydro potential in this basin within the scope of the 4628 Electricity Market Law. With this law, concerning the restructuring of the electricity market, private sector investments in this segment have increased. In total, 1524 hydroelectric power projects with 22 360 MW installed capacity has been implemented until January 22nd, 2009 and this figure is continuously rising.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    İncele
  • BildiriYalnız künye2011
    Operational modal testing of an arch type steel highway bridge using SSI technique

    Altunişik, A.C.; Bayraktar, A.; Sevim, B.

    The paper determines the dynamic characteristics of an arch type steel highway bridge applying ambient vibration testing. A modern steel highway bridge which has arch type structural system with 216m total length and located in the Ayvacik county of Samsun, Turkey is selected as an application. Because of the fact that the bridge connects the villages which are separated with Suat Ugurlu Dam Lake, it has a major logistical importance for this region. The construction of the bridge completed in 2009 and opened the traffic. The experimental meas-urements are carried out by ambient vibration tests under traffic loads. Vibration data are gath-ered from the bridge deck. Measurement time, frequency span and effective mode number are determined considering similar studies in the literature and initial finite element analysis re-sults. Stochastic Subspace Identification technique (SSI) in the time domain are used for the output only modal identification and dynamic characteristics such as natural frequencies, mode shapes and damping ratios are determined, experimentally.

    İncele
  • MakaleYayıncıda açık erişim2011
    Analysis of support requirements for a tunnel portal in weak rock: A case study from Turkey

    Kaya, Ayberk; Bulut, Fikri; Alemdaǧ, Selçuk; Sayin, Aytuna

    In this paper, engineering geological properties of the entrance portal section of Konakönü Tunnel, located on Black Sea Coastal Highway, Turkey, is studied. Moderately weathered basaltic and andesitic tuffs orderly to be driven by the entrance portal section. Tunnel portal design in weak rock presents some special challenges to the designers, since misjudgements in the design of tunnel can lead to very costly failures. The entrance portal was analyzed by empirical and numerical methods. Both field and laboratory studies were carried out during this study. Field studies involved geological mapping, detailed discontinuity surveying and sampling. Laboratory tests were carried out to determine the physico-mechanical and elastical properties of rock units. For this purpose, tunnel stability analyses were performed at the entrance portal section. The RMR (rock mass rating), Q (rock mass quality), RMi (rock mass index), NATM (new Austrian tunnelling method) and GSI (geological strength index) systems were employed for empirical rock mass quality determination and preliminary tunnel portal support design. The parameters calculated by the empirical methods were used as input parameters for the FEM (finite element method) analysis. The results from the two methods were compared and preliminary support designs were carried out. This comparison suggests that for more reliable support design, empirical and finite element methods should be combined.

    İncele
  • MakaleYalnız künye2011
    The effect of fin pitch on heat transfer and fluid flow characteristics in the entrance region of a finned concentric passage

    Kuvvet, Kemal; Yavuz, Tahir

    In this study, the heat transfer and fluid flow characteristics in the unfinned and internally finned concentric passage (smooth and finned annulus) are investigated experimentally. The turbulence characteristics, mean flow, pressure drop and heat-transfer parameters in the entrance region of a concentric passage of diameter ratio 0.2 are measured. The hot-wire anemometer and the liquid-crystal technique are used for the turbulence and mean flow and the heat transfer measurements, respectively. The finned passage is designed as the fin width (W) of 2 mm, the fin height (H) of 2, 4, 6 and 8 mm and the fin pitch (P) of 20, 30 and 40 mm. Reynolds number ranges from 1.8 .104 to 1.24.105 and from 1.65.104 to 7.65.104 for flow and pressure drop and heat transfer measurements, respectively. Experiments are performed for the smooth and finned concentric passages by varying flow and fin parameters and the effects of the fin pitch are investigated. The developing of fluid flow is analyzed and the variation of turbulence intensity, friction factors, local and mean convective heat transfer coefficients in the smooth and finned concentric passages are obtained. Results obtained in the finned concentric passages are compared with the results of the smooth passage. For the average Nusselt numbers and friction factor, empirical equations are developed. As a result, it is seen that the friction factor in the finned passage increases between 3.61 and 18.05 times while the average Nusselt number augments between 1.36 and 5.23 times on the inner surface and between 1.03 and 1.80 times on the outer surface.

    İncele
  • MakaleYalnız künye2011
    Determination of seasonal changes in olive oil by using differential scanning calorimetry heating thermograms

    Ilyasoglu, Huri; Ozcelik, Beraat

    Thermal properties (upon heating) of extra virgin olive oils (EVOOs) from Aegean cultivars were determined to evaluate the possibility of using differential scanning calorimetry (DSC) as a tool for monitoring seasonal changes in chemical composition. Chemical properties of the samples were analyzed to assess the relationship between the thermal properties and chemical properties as well. The thermal properties of Aegean cultivars were found to be influenced by major components (palmitic acid, oleic acid, linoleic acid, triolein and palmitodiolein). The melting offset temperature, the temperature range of melting and the melting enthalpy of Aegean cultivars presented significant differences with respect to crop season (p < 0.05). DSC may be utilized to evaluate compositional changes with respect to crop season.

    • SDG 2 · Açlığa Son
    İncele
  • MakaleYalnız künye2011
    Petrochemistry and U-Pb zircon ages of adakitic intrusions from the pulur massif (eastern pontides, ne Turkey): Implications for slab rollback and ridge subduction associated with Cenozoic convergent tectonics in the eastern Mediterranean

    Eyuboglu, Yener; Santosh, M.; Chung, Sun-Lin

    The well-preserved magmatic arc in the eastern Pontides orogenic belt of northeastern Turkey offers critical clues on convergent margin tectonics associated with the late Mesozoic-early Cenozoic geodynamic evolution of the eastern Mediterranean region. Here we investigate the petrology, geochemistry, and U-Pb zircon chronology of adakitic intrusions from the Pulur region in the southern zone of the eastern Pontides belt. The intermediate to felsic intrusives in the Pulur region are characterized by the presence of abundant plagioclase, amphibole, and biotite phenocrysts. The rocks display extreme light rare earth element enrichment (LaN YbN p13.69-51.08); high Al2O3 (15.46-17.47 N Nwt%), Na2O (3.57-8.43 wt%), Sr (324.8-1468 ppm), and La (13.9-55.8 ppm) concentrations; a high Sr/Y ratio (35-473); and low Y (3-12.6 ppm) and heavy rare earth element concentrations, closely comparing with the typical features of adakites. Zircons extracted from the Pulur adakites show euhedral crystal shapes, oscillatory zoning patterns, andhigh Th/U ratios (up to 3.33) consistent with their magmatic origin. Their 206Pb/238U ages show a range of 55.21-53.07 Ma, correlating the magmatism to the early Eocene. We propose a tectonic model involving the initiation of a slab rollback and simultaneous opening of a slab window during ridge subduction in a south-dipping sub duction zone for the origin of the Tertiary adakitic and nonadakitic magmatism in the eastern Pontides orogenic belt. We also identify a close relation between slab rollback processes and back arc extension, which led to the opening of the Tertiary basins in the southern part of the eastern Pontide orogenic belt. The eastern Pontide orogenic belt is one of the world's largest metallogenic provinces, and it hosts various economic mine ralizations such as volcanogenic massive sulfide, epithermal gold-silver, porphyry copper-molybdenum, skarn-type, and chromite. However, the adakitic intrusions exposed in the southern part of the eastern Pontide orogenic belt are devoid of ore deposits, which leads us to propose that the Lutetian or later nonadakitic granitic intrusions exposed at the north of the Gumushane-Bayburt-Ispir line were probably responsible for the epithermal gold mineralization in this belt.

    İncele
  • MakaleYalnız künye2011
    Mild and severe anal incontinence after lateral internal sphincterotomy: Risk factors, postoperative anatomical findings and quality of life

    Kement, M.; Karabulut, M.; Gezen, F.C.; Demirbas, S.; Vural, S.; Oncel, M.

    Aim: This study aims to evaluate the risk factors for incontinence after lateral internal sphincterotomy (LIS) and assess quality of life in different levels of incontinence. Methods: All consecutive patients (n = 253) with chronic anal fissure who underwent LIS between 2003 and 2006 were retrospectively reviewed. All patients were questioned for possible anal incontinence according to the Wexner Incontinence Score (WIS). Demographics, vaginal delivery history, additional procedures and surgeon's experience were evaluated as risk factors. Endoanal ultrasound (EUS) was performed in incontinent patients to assess the thickness of the remaining internal sphincter and to evaluate any injury in the external sphincter. Quality of life was questioned with SF-36. Results: Twenty-eight (11.7%) patients suffered from incontinence (mean WIS = 3.6 ± 2.5). The search for a risk factor was unsuccessful when continent and incontinent groups were compared. In subgroup analyses, patients were found to be suffering from mild (WIS <5, n = 19) or severe (WIS >5, n = 9) incontinence. Vaginal delivery history was found more often in the severely incontinent subgroup than in the continent group (p < 0.05). Also, vaginal delivery history and the additional procedures were more frequently observed in the severely incontinent subgroup than in the mildly incontinent subgroup. EUS did not find any external sphincter injury in these cases. WIS had negative correlations with the physical and mental component scores of SF-36. Conclusion: In our opinion, the threat for incontinence is unpredictable; however, vaginal delivery history may increase the risk of severe incontinence.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    İncele
  • MakaleYalnız künye2011
    Finite element model calibration of berke arch dam using operational modal testing

    Sevim, Bariş; Bayraktar, Alemdar; Altunişik, Ahmet Can

    This paper presents the finite element calibration of Berke Arch Dam by using Operational Modal Testing. Achievement of this purpose involves structural vibration characteristics of Berke Arch Dam using analytical and Operational Modal Analyses. Therefore, the study has two parts-analytical and experimental. In the analytical part of the study, the authors developed a 3D finite element model of Berke Arch Dam-reservoir-foundation system using ANSYS software, and analytically determined vibration characteristics such as natural frequencies and mode shapes. In the experimental part of the study, sensitive accelerometers were placed to several points of Berke Arch Dam, and ambient vibration tests were conducted over four days to obtain dynamic characteristics. The Enhanced Frequency Domain Decomposition technique is used to estimate natural frequencies, mode shapes and damping ratios of the Berke Arch Dam experimentally. Results showed that there were some differences between analytical and experimental natural frequencies of the dam. Therefore, an analytical model of Berke Arch Dam was calibrated to minimize these differences by changing material properties. Analytical results obtained from the calibrated model mainly conform to those of the experimental model.

    İncele
  • MakaleYalnız künye2011
    Solid waste management practices in Turkey

    Berkun, Mehmet; Aras, Egemen; Anılan, Tugce

    As an economically developing country, Turkey has very well operated integrated solid waste management applications structured on modern facilities, besides over 2,000 scattered open dump areas in the country. Integrated waste management applications seem eligible for the metropolitan cities like Istanbul and Izmit (Kocaeli). Attempts have not been encouraging for the scattered regional settlements using central storage sites due to financial shortages and received rejections from nearby settlements. Small-scale compact solid waste management systems with materials recycling and composting can be more suitable alternatives in the small-scale regional settlements. The major constituents of municipal solid waste are organic in nature and approximately a quarter of municipal solid waste is recyclable. Although paper, including cardboard, is the main constituent, the composition of recyclable waste varies strongly by the source or the type of collection point. Solid wastes need primary treatment in order to be suitable for incineration and composting. Turkey needs to give more emphasis on the usage of modern solid waste removal technologies to overcome the overgrowing solid waste disposal problems.

    • SDG 11 · Sürdürülebilir Şehirler ve Topluluklar
    • SDG 12 · Sorumlu Üretim ve Tüketim
    İncele
  • BildiriYalnız künye2011
    Hydroxyapatite production on ultrafine-grained pure titanium by micro-arc oxidation and hydrothermal treatment

    Alsaran, A.; Purcek, G.; Hacisalihoglu, I.; Vangolu, Y.; Bayrak, O.; Karaman, I.; Celik, A.

    In this study, pure-Ti (Grade-2) was severely plastically deformed by equal-channel angular extrusion (ECAE) to improve its strength, and then subjected to micro arc oxidation (MAO) and hydrothermal treatment (HT) to achieve improved surface behavior with hydroxyapatite (HA)-containing titania (TiO(2)) coating. Microstructure, tensile properties and wear behavior of UFG Ti were investigated systematically before and after surface modification. ECAE considerably enhanced the strength of coarse-grained (CG) Ti by forming an ultra-fine grained (UFG) microstructure with high dislocation density. The application of MAO with or without HT did not cause remarkable decrease in strength and ductility of CG and UFG Ti, but resulted in a considerable increase in its wear resistance and osseointegration due to the formation of hard and adhered HA-containing TiO2 coating on the surface. It can be concluded that the use of ECAE plus MAO/HA coating provides a simple and effective procedure to obtain pure Ti with high strength and high wear resistance. The improved bulk and surface properties can make this biocompatible material a good potential candidate for biomedical applications instead of alloys including toxic elements. (C) 2011 Elsevier B.V. All rights reserved.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    İncele
  • MakaleAçık Erişim2011
    Transition from shoshonitic to adakitic magmatism in the eastern Pontides, NE Turkey: Implications for slab window melting

    Eyuboglu, Yener; Chung, Sun-Lin; Santosh, M.; Dudas, Francis O.; Akaryali, Enver

    The formation of the eastern Pontides orogenic belt has been widely assigned to a northward subduction of the Neotethyan oceanic slab during the late Mesozoic-Cenozoic. Here we provide an alternate model based on new geological, geochemical and isotopic data. The magmatic activity in the far south of the belt started in the early Campanian with shoshonitic trachyandesites and associated pyroclastics. This sequence is covered by the late Campanian-early Maastrichtian reefal limestones and another stage of high-K volcanism represented by analcimized leucite-rich ultrapotassic rocks of the Maastrichtian-early Paleocene (?) ages. The shoshonitic and ultrapotassic rocks, with K2O contents ranging from 0.26 to 6.95 wt.%, display broadly similar rare earth and multi-element distribution patterns. Both rock types are enriched in LILE and LREE and depleted in HFSE (Nb,Ta and Ti), suggesting a subduction-enriched mantle source for the magma generation. Subsequently, during the late Paleocene, a stage of acidic magmatism (SiO2 of 53.25-73.61 wt.%) that shows adakitic geochemical characteristics including high Sr/Y (46-416) and La/Yb (11-51) and low Y (2.6-12.2 ppm), is documented characterized by melting of a mafic source such as the MORB crust with garnet in the residue. The adakitic magmatism began at similar to 56 Ma and migrated toward the north through time, culminating with porphyritic andesites (similar to 47 Ma) that were emplaced in the Gumushane-Bayburt line and its vicinity. North of this line, coeval magmas show typical calc-alkaline nature and continued to develop toward further north until the middle to late Eocene. Based on the spatial and temporal variations in the magmas generated in the eastern Pontides orogenic belt, we propose a new geodynamic model to explain the tectonomagmatic evolution of these rocks and correlate the adakitic magmatism to ridge subduction and slab window process within a south-dipping subduction zone. Our model is in contrast to the previous proposals which envisage partial melting or delamination of thickened lower continental crust due to the collision in the south during the Paleocene-Eocene. (C) 2010 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

    İncele
  • MakaleYalnız künye2011
    Adakite-like granitoid porphyries in the Eastern Pontides, NE Turkey: Potential parental melts and geodynamic implications

    Karsli, Orhan; Ketenci, Murat; Uysal, Ibrahim; Dokuz, Abdurrahman; Aydin, Faruk; Chen, Bin; Kandemir, Raif; Wijbrans, Jan

    The tectonic setting of the Eastern Pontides during the late Mesozoic to early Cenozoic remains a subject of debate. Petrogenesis of adakite-like granitoid porphyries plays a critical role in determining the nature of the lower continental crust and mantle dynamics during orogenic processes in the region. Here we describe, for the first time, the late Paleocene to early Eocene adakite-like granitoid porphyries from the northern part of the Eastern Pontides although their counterparts in the southern part have recently been found. The adakitic porphyries, which emplaced into the subduction-related Turonian-Santonian volcanics from northern part of the region, consist of I-type calc-alkaline quartz monzonite-tonalite (SiO2 = 62.89-65.07 wt.%) and high-k calc-alkaline granodiorite-granite associations (SiO2 = 69.06-70.43 wt.%). The former displays peraluminous to metaluminous signatures, whereas the latter shows peraluminous geochemical character. The granite-granodiorite porphyries have high K2O (3.32-3.84 wt.%), and low Na2O (3.48-4.61 wt.%) and MgO (0.91-1.04 wt.%) relative to the quartz monzonite-tonalite association (K2O = 1.50-1.92 wt.%; Na2O = 4.08-6.45 wt.%; MgO = 1.44-2.07 wt.%). Ar-Ar geochronology studies on the amphibole separates reveal that the adakite-like porphyries have a crystallization ages of 51.34 +/- 0.27 to 53.55 +/- 0.34 Ma. Here, we contend that these rocks were formed by partial fusion of a mafic lower continental crust in a collisional phase but not in a subduction setting. All the samples exhibit the typical geochemical characteristics of adakite, that is, high Sr (250-1141 ppm), high Sr/Y ratios (16-147), low Y (6.8-14.8 ppm) and low HREE concentrations; they are similar to adakites formed by slab melting associated with the subduction zone. However, the rocks exhibit heterogeneity in isotopic composition, with I-Sr ranging from 0.70554 to 0.70986, epsilon(Nd) (51 Ma) from -8.5 to -0.9 and Nd model ages from 0.72 to 1.26 Ga. The samples are characterized by relatively high Th, Th/U and no significant Eu anomalies, implying that garnet was stable in their source during partial melting. The compositional diversity between rock groups is probably related to partial melting of heterogeneous lower crustal source. All of the features are inconsistent with a slab-melting origin and slab-related petrogenetic model, but instead, they favor an origin by melting of heterogeneous lower continental crust due to a thermal anomaly that was induced by the upwelling of the asthenosphere through a slab break-off in a collisional setting. These interpretations argue against the evidence for the presence of an early Cenozoic arc setting in the Eastern Pontides. Instead, the early Cenozoic time in the region may be attributed to a geodynamic response to a post-collisional uplift phase that occurred along the continent-continent collision between the Pontide and the Anatolide-Tauride blocks. (C) 2011 Elsevier B.V. All rights reserved.

    İncele
  • MakaleYalnız künye2011
    Migrating magmatism in a continental arc: Geodynamics of the Eastern Mediterranean revisited

    Eyuboglu, Yener; Santosh, M.; Dudas, Francis O.; Chung, Sun-Lin; Akaryali, Enver

    The eastern Pontide orogenic belt in Turkey offers a critical region to evaluate the geodynamic evolution of the eastern Mediterranean region during the late Mesozoic-Cenozoic. Here we synthesize results from our exhaustive database on the geochemical characteristics of adakitic magmatism from 137 bodies covering 7 domains in the southern zone of eastern Pontides. Together with new Pb-Sr-Nd results, we show that the adakitic magmatism in the eastern Pontide belt is clearly linked to slab window processes during ridge subduction, as against the earlier models that assumed partial melting of a delaminated or thickened lower continental crust following collision. The isotopic compositions display a complex pattern and suggest mixing of multiple source materials such as depleted mantle, enriched lithospheric mantle, and upper crust. We also confirm a southward polarity of subduction as against the previous models that assumed a northward subduction. We supplement our model with evidence for a northward propagation of the adakitic magmatism, spatial and temporal variations in arc magmatism, presence of south-dipping reverse faults and a synthesis of the available paleomagnetic data. Our studies also suggest that the Black-Sea is a remnant of the Tethyan ocean that was situated to the north of the arc during the late Mesozoic-Cenozoic as against the correlation to a late Mesozoic-Cenozoic back-arc basin related to a northward subduction of the Paleo- or Neo-tethyan oceanic lithosphere in alternate models. (C) 2010 Elsevier Ltd. All rights reserved.

    İncele