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    Collision-related granite magma genesis, potential sources and tectono-magmatic evolution: comparison between central, northwestern and western Anatolia (Turkey)
    (Taylor & Francis Inc, 2009) Ilbeyli, Nurdane; Kibici, Yasar
    The central, northwestern and western Anatolian magmatic provinces are defined by a large number of late Mesozoic to late Cenozoic collision-related granitoids. Calc-alkaline, subalkaline and alkaline intrusive rocks in central Anatolia are mainly metaluminous, shoshonitic, I- to A-types. They cover a petrological range from monzodiorite through quartz monzonite to granite/syenite, and are all enriched in LILE. Their geochemical characteristics are consistent with formation from a subduction-modified mantle source. Calc-alkaline plutonic rocks in northwestern Anatolia are mainly metaluminous, medium- to high-K and I-types. They are monzonite to granite, and all are enriched in LILE and depleted in HFSE, showing features of arc-related intrusive rocks. Geochemical data reveal that these plutons were derived from partial melting of mafic lower crustal sources. Calc-alkaline intrusive rocks in western Anatolia are metaluminous, high-K and I-types. They have a compositional range from granodiorite to granite, and are enriched in LILE and depleted in HFSE. Geochemical characteristics of these intrusive rocks indicate that they could have originated by the partial melting of mafic lower crustal source rocks.
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    Contemporaneous Late Cretaceous Calc-alkaline and Alkaline Magmatism in Central Anatolia, Turkey: Oxygen Isotope Constraints on Petrogenesis
    (Tubitak Scientific & Technological Research Council Turkey, 2009) Ilbeyli, Nurdane; Pearce, Julian A.; Meighan, Ian G.; Fallick, Anthony E.
    A wide variety of rock types were produced by the latest Cretaceous magmatism in the Central Anatolian Crystalline Complex. These rocks can be divided into three distinct units: (i) calc-alkaline, (ii) subalkaline/transitional, and (iii) alkaline. The calc-alkaline rocks are mainly metaluminous (I-type) ranging from monzodiorite to granite. The subalkaline/ transitional rocks are also metaluminous (I-type) ranging from monzonite to granite. The alkaline rocks are mainly peralkaline (A-type), ranging from feldspathoid-bearing monzosyenite to granite. Whole-rock oxygen isotope data from the complex have a considerable range of delta O-18 values between 6.5% and 14.8%. Initial Sr-87/Sr-86 versus Nd-143/Nd-144 ratios, and both ratios versus d18O values diagrams show that the intrusive rocks are derived from a subduction-modified mantle and also have experienced fractional crystallisation coupled with crustal assimilation. Delamination of a thermal boundary layer, and/or slab breakoff is the likely mechanisms for the initiation of the diverse magmatism in the complex.
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    Geochemical characteristics of the Sebinkarahisar granitoids in the Eastern Pontides, northeast Turkey: Petrogenesis and tectonic implications
    (Taylor & Francis Inc, 2008) Ilbeyli, Nurdane
    A series of Cretaceous to Eocene granitoids are present in the Eastern Pontides of northeastern Turkey. The Asarcik (Saplica, Catakhan), Eskine, and Saydere (Sebinkarahisar-Giresun) are the least-studied, thus least-understood plutons in the orogen. Rock assemblages range from monzonite to granite. They contain mainly K-feldspar, plagioclase, quartz, hornblende, biotite, and Fe-Ti oxides. They are high-K, calc-alkaline, and I-type granites. Chondrite-normalized REE patterns are fractionated and have small negative Eu anomalies. They show enrichment in LILE and LREE relative to HFSE, displaying features of arc-related granitoids. Low molar Al2O3/(FeO+MgO+TiO2) in combination with variable molar (Na2O+K2O)/(FeO+MgO+TiO2) ratios indicate that the magmas were derived from mafic lower-crustal source rocks. The Eu and Sr anomalies and unfractionated HREE Suggest the presence of plagioclase and absence of garnet in the source.
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    Geochemical comparison of ultramafic-mafic cumulate rocks from the Central Anatolian ophiolites, Turkey
    (Taylor & Francis Inc, 2008) Ilbeyli, Nurdane
    Ophiolites, formed during closure of the Neo-Tethyan ocean, are widespread in Turkey and have been extensively studied. In addition to ophiolites showing recognizable stratigraphic sequences, numerous massive and layered gabbroic masses occur as isolated outcrops in the Central Anatolian Crystalline Complex. An example from the Akeakent region ranges from gabbro to diorite; another, from the Kustepe area, is characterized by dunite, wehrlite, troctolite, olivine gabbro, clinopyroxene gabbro, clinoproxene hornablende gabbro, uralite gabbro, and fine-grained gabbro. Samples from bothe regions desplay adcumulate and orthocumulate textures and show low-K and subalkaline characters; they are enriched in some LILE (e.g. Sr, Rb, K, Ba) and depleted in HFSE (e.g., Ta, Nb, Zr, Ti) relative to N-MORB. Petrological data, negative Ta, Nb, Zr, Ti anomalies, and ratios of elements such as Ba/Nb and La/Nb indicate a suprasubduction setting for the central Anatolian ultramafic-mafic rocks, suggesting that both rock types may have formed in a backare setting.
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    Geochemical constraints on the genesis of the Gunyuzu pluton, northwest Anatolia, Turkey
    (Taylor & Francis Inc, 2008) Kibici, Yasar; Ilbeyli, Nurdane; Yildiz, Ahmet; Bagci, Metin
    Tavsanli Zone in northwest Turkey is intruded by many Late Cretaceous to Eocene (91-45 Ma) calc-alkaline granitoids, of which the Gunyuzu pluton in the Eskisehir region is the least studied. The Gunyuzu rocks are high-K, calc-alkaline (I-type) intrusions. and are comprised of diorite, granodiorite, granite, and granite porphyry. Typical minerals are plagioclase, K-feldspar, quartz, biotite, hornblende and Fe-Ti oxides. Chondrite-normalized REE patterns for the Gunyuzu rocks are moderately fractionated and have small negative Eu anomalies. They are enriched in LILE and LREE relative to HFSL, showing characteristics of arc-related granitoids. Low values of molar K2O/Na2O, Al2O3/(FeO+MgO+TiO2). and (Na2O+K2O)/(FeO+MgO+TiO2) ratios demonstrate that the Gunyuzu magma(s) were produced from mafic lower crustal rocks.
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    Insight into magma genesis at convergent plate margins - a case study from the eastern Pontides (NE Turkey)
    (E Schweizerbartsche Verlagsbuchhandlung, 2010) Kaygusuz, Abdullah; Siebel, Wolfgang; Ilbeyli, Nurdane; Arslan, Mehmet; Satir, Muharrem; Sen, Cuneyt
    Convergent plate margins are the most intense areas of granitoid magmatism on Earth. The Eastern Pontide Magmatic Belt in NE Turkey represents a paleo-arc with numerous quartz diorite to syenite intrusions, ranging in age from 142 to 56 Ma and being composed of K-feldspar, plagioclase, quartz, pyroxene, hornblende, biotite, and Fe-Ti oxides. The granitoids exhibit low-to high-K calc-alkaline, metaluminous to slightly peraluminous I-type features and contain abundant mafic magmatic enclaves (MME). They are characteristically enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) relative to high field strength elements (HFSE). Chondrite-normalized REE patterns are fractionated (La-N/Lu-N = 1.49-17.4) with pronounced negative Eu anomalies (Eu/Eu* = 0.46-1.77). Initial Sr-87/Sr-86 values are between 0.7056 and 0.7079, and epsilon(Nd(i)) values between -5.3 and 1.6. Fractional crystallization, magma mixing/mingling and crustal contamination played an important role during magma evolution. All these characteristics, combined with the low values of K2O/Na2O, Mg-number, ASI and ratios of Al2O3/(FeOT+MgO+TiO2) and (Na2O+K2O)/(FeOT+MgO+TiO2), suggest an origin by dehydration melting of mafic (amphibolitic) or tonalitic lower crustal source rocks.
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    Petrogenesis of the Late Cenozoic Egrigoz pluton in western Anatolia, Turkey: implications for magma genesis and crustal processes
    (Taylor & Francis Inc, 2008) Ozgenc, Ismet; Ilbeyli, Nurdane
    The western Anatolian magmatic province is typified by a large number of Late Cenozoic post-collisional granitoids. Of these magmatics, the Egrigoz pluton is one of the largest and least-understood plutons in the Menderes Massif. The Egrigoz intrusives are subalkaline, high-K, and calc-alkaline, and have characteristics of I-type granites. They consist mainly of granodiorite and granite. The intrusive rocks show enrichment in LILE and LREE relative to HFSE. Their chondrit-enormalized REE patterns are fractionated and have small negative Eu anomalies. Geochemical characteristics of the Egrigoz pluton indicate an origin through partial melting of mafic lower-crustal source rocks. In western Anatolia, the melt generation mechanism for the intrusive rocks could be crustal extension and uplift following collision.