72 research outputs found

    Petrogenesis of collision-related plutonic rocks, central Anatolia(Turkey)

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    Central Anatolia exhibits good examples of calc-alkaline and alkaline magmatism of similar age in a collision-related tectonic setting (continent-island arc collision). In the Central Anatolia region, post-collisional plutonic rocks (around 79.5 to 66.6 Ma) intrude Palaeozoic-Mesozoic metamorphic rocks overthrust by Upper Cretaceous ophiolitic units to make up the Central Anatolian Massif. In the Massif, three different intrusive rock types are recognised based on their geochemical characteristics: (i) calc-alkaline (Behrekdag, Cefalikdag, Celebi-BCC); (ii) transitional (Baranadag-B); and (ii) alkaline (Hamit-H). The BCC and B plutonic rocks are metaluminous, I-Type ranging from monzodiorite to granite. The H plutonic rocks are metaluminous to peralkaline, predominandy A-Type ranging from nepheline monzosyenite to quartz syenite. Two types of igneous enclave have been recognised in the BCC plutonic rocks; (i) fine-grained (Type-I); and (ii) medium-grained to porphyritic with feldspar megacrysts (Type-II). Field, petrographic and geochemical evidence suggest that the Type-I enclaves originated from injection of mafic magma into more silicic magma. Field, petrographic and mineralogical evidence together with major and trace element geochemistry suggest that the Type-II enclaves formed as cumulates of early-crystallised minerals (e.g. clinopyroxene, plagioclase, amphibole and biotite) from the granitoid magmas. All intrusive rocks show enrichment in LILE and LREE relative to HFSE and have high (^87)Sr/(^86)Sr and low (^143)Nd/(^144)Nd ratios. These characteristics indicate an enriched mantle source region(s) carrying a subduction component inherited from pre-collision subduction events. Rb, Nb, Y versus SiO(_2) diagrams and the tectonic discrimination diagram of Rb and the (Y+Nb) suggest that the BCC, B and H plutonic rocks have been affected by crustal assimilation combined with fractional crystallisation processes. Coexistence of calc-alkaline and alkaline magmatism in the Central Anatolian Massif has been attributed to mantle source heterogeneity before collision. Either thermal perturbation of the metasomatised lithosphere by delamination of the thermal boundary layer (TBL) or removal of a subducted plate (slab breakoff) are the likely mechanisms for the initiation of the post-collisional magmatism in the Massi

    Contemporaneous late cretaceous calc-alkaline and alkaline magmatism in Central Anatolia, Turkey: oxygen isotope constraints on petrogenesis

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    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 δ18O values between 6.5‰ and 14.8‰. Initial 87Sr/86Sr versus 143Nd/144Nd ratios, and both ratios versus δ18O 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

    Perceived esthetics and value of clear aligner therapy systems: A survey among dental school instructors and undergraduate students.

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    OBJECTIVE To investigate the attractiveness, acceptability, visibility and willingness-to-pay for clear aligner therapy (CAT) systems in first-year and final-year dental students and instructors. METHODS A questionnaire designed to collect information regarding esthetic preferences and intentions related to seven CAT systems was handed out to 120 undergraduate students and instructors at the Academic Centre for Dentistry Amsterdam (ACTA). Proportional odds models and population average generalized estimating equation models were used to examine potential association between participant characteristics, esthetic perceptions and CAT systems. RESULTS Overall, the examined CAT systems received favorable esthetic ratings. Expertise status was significantly associated with willingness-to-pay additionally for CAT, compared to fixed orthodontic appliances. There was no association between sex, previous orthodontic treatment history, satisfaction with own dental appearance and potential interest in treatment and aligner visibility and willingness-to-pay. CAT system was significantly associated with the perceived aligner visibility, acceptability and attractiveness by students and instructors. CONCLUSIONS CAT systems were considered to a great extent attractive and acceptable for future treatment by dental school instructors and students. Willingness-to-pay for CAT systems was significantly associated with expertise status, with instructors appearing more reluctant to pay for CAT

    Coeval extensional shearing and lateral underflow during Late Cretaceous core complex development in the Niğde Massif, Central Anatolia, Turkey

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    27 p.International audienceThe Nig¢de Massif, at the southern tip of the Central Anatolian Crystalline Complex, consists of two structural units. Foliations in the lower unit define a dome cored by migmatites. The contact between the two units bears all the elements of a ductile to brittle extensional detachment. Hence the Nig¢de Massif represents an extensional metamorphic core complex. Top-to-NE/ENE shearing at higher levels of the lower unit relates to displacement along the detachment. Deeper levels of the lower unit display hightemperature top-to-SSW ductile shearing. The two shearing deformations show a difference in the mean trend of stretching lineations of up to 58. New 40Ar/39Ar ages combined with previously published data enable us to infer that the two shears were contemporaneous. In our favored interpretation, oblique shearing in the core of the dome reflects lateral underflow, i.e., horizontal flowing of the lower crust in a direction highly oblique to the direction of extension. As a result of the interaction between lateral underflow and downdip shearing along the overlying detachment, distinct structural domains are expected to exist within the migmatitic part of the core complex, with observed counterparts in the Nig¢de dome. Lateral underflow may reflect ''inward'' flow on the scale of the core complex. Regional-scale channel flow is an alternative that would better account for the record of non-coaxial deformation in the core of the dome. More generally, we suspect that the development of lateral underflow in a metamorphic core complex more likely reflects regional channel flow, rather than local inward flow

    Alt ekstremite primer malign ve metastatik kemik tümörlerinde rezeksiyon artroplastisi sonuçları

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    TEZ5366Tez (Uzmanlık) -- Çukurova Üniversitesi, Adana, 2005.Kaynakça (s. 77-82) var.vii, 93 s. : rnk. res. ; 29 cm.

    Orta Anadolu Kristalen Kompleksi' nde bulunan Hamit alkalen intrüzyonunun arazi, petrografik ve jeokimyasal özellikleri, Türkiye

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    Hamit plütonu, Orta Anadolu Kristalen Kompleksi (OAKK) içerisinde yeralan alkalen intrüzyonlardan biridir. Plüton, nefelin siyenit, psödolösit siyenit, alkali feldspat siyenit ve kuvars siyenitden meydana gelir. Nefelin siyenit ve psödolösit siyenit, foidli mikrosyenitik dayklar tarafından kesilirken, alkali feldspat siyenit ve kuvars siyenit ise aplitik ve silisli dayklar tarafından kesilir. Peraikalen Hamit intrüzif kayaçları arazi, petrografik ve jeokimyasal özellikleri ile A-tipi granitlere benzerlik gösterirler. Tüm intrüzif kayaçlar HFSE nazaran, LILE ve LREE ile zenginleşmiştir. Th/Yb-Ta/Yb diyagramı, intrüzif kayaçlar için kaynak bölgesinin, çarpışma öncesi dalma-batma olayı ile zenginleşmiş manto olduğunu göstermektedir. Kompleks de çarpışma sonrası magmatizmanın başlangıcı için uygun mekanizmalar, ya metasomatize olmuş litosferin termal sınır tabakasının (TST) delaminasyonu ya da dalmakta olan levhanın (kırılıp?) yok edilmesidir (slab breakoff).The Hamit pluton is one of the alkaline intrusions in the Central Anatolian Crystalline Complex (CACC). The pluton consists of nepheline syenite, pseudoleucite syenite, alkali-feldspar syenite and quartz syenite. The nepheline syenite and pseudoleucite syenite are cut by fold-bearing microsyenitic dykes, whereas the alkali-feldspar syenite and quartz syenite are cut by aplitic and silicic dykes. The predominantly peralkaline Hamit intrusive rocks possess field, petrographic and geochemical characteristics comparable to A-type granites. All intrusive rocks of this pluton show enrichment in LILE and LREE relative to HFSE. The Th/Yb versus Ta/Yb plot suggests that the intrusive rocks formed from an enriched mantle source region carrying a subduction component inherited from pre-collision subduction events. Either thermal perturbation of the metasomatised lithosphere by delamination of the thermal boundary layer (TBL) or removal of a subducted plate (slab breakoff) are the likely mechanisms for initiation of the post-collisional magmatism of this complex

    Petrogenesis and geochemical characteristics of the Subalkalen Baranadağ Pluton (Kaman - Kırşehir)

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    Orta Anadolu Kristalen Kompleksi'nde kalk-alkalenden alkalene kadar değişen farklı bileşimli kayaçlar bulunmaktadır. Bunlardan bir tanesi de, monzonit ve kuvars monzonit bileşimli Baranadağ plütonudur. Plüton, subalkalen ve metalümin karakterde olup, mafik magmatik anklav ve potasyumlu feldispat megakristalleri içerir. Baranadağ plütonu, aplitik, pegmatitik ve mikrosiyenitik dayklar tarafından kesilmiştir. Baranadağ intrüzif kayaçları arazi, petrografik ve jeokimyasal özellikleri ile I-tipi granitlere benzerlik göstermektedirler. Baranadağ plütonik kayaçlannın toplam alkali (Na2O+K2O) ve Rb değerleri yüksektir. Bu kayaçlar ayrıca HFSE' e nazaran, LILE ve LREE bakımından zenginleşmiştir. Th/Yb-Ta/Yb dağılımı, intrüzif kayaçlar için kaynak bölgesinin çarpışma öncesi dalma-batma ile zenginleşmiş olan manto olduğunu göstermektedir.Within the Central Anatolian Crystalline Complex different rock types in composition from calc-alkaline to alkaline are found. One of these is the Baranadağ pluton containing monzonite and quartz monzonite. This pluton has subalkaline and metaluminous characteristics, and includes mafic igneous enclaves and potassium feldspar megacrysts. The Baranadağ pluton is cut by aplitic, pegmatitle and microsyenitic dykes. The Baranadağ intrusive rocks show comparable field, petrographic and geochemical characteristics with I-type granites. The Baranadağ plutonic rocks have high total alkali (Na2O+K2O) and Rb values. In addition, these rocks show enrichment in LILE and LREE relative to HFSE. The Th/Yb versus Ta/Yb plot displays that the intrusive rocks formed from an enriched mantle source region carrying a subduction component inherited from pre-collision subduction events

    Geochemical constraints on petrogenesis of Late Cretaceous alkaline magmatism in east-central Anatolia (Hasancelebi-Basoren, Malatya), Turkey

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    Late Cretaceous alkali magmatic rocks occur widely in the Hasancelebi and Basoren regions (Malatya). The Hasancelebi and Basoren intrusive rocks are mainly peralkaline and alkaline-oversaturated. The Hasancelebi intrusive rocks are made up of syenite to quartz monzonite. On the other hand the Basoren intrusive rocks mainly contain feldspathoidal syenites that are cut by feldspathoid-bearing dykes. The Hasancelebi intrusive rocks show comparable field, petrographic and geochemical characteristics with A-type rocks. All intrusive rocks show enrichment in LILE and LREE relative to HFSE. The Th/Yb versus Ta/Yb diagram indicates that all magmatic rocks formed from an enriched mantle source region(s). The parental magma for the Basoren rocks has a higher intraplate component than that from the Hasancelebi rocks which could be attributed to mantle source heterogeneity before collision in east-central Anatolia. Either delamination of the thermal boundary layer or slab-breakoff are likely mechanisms for the initiation of post-collisional magmatism in the Hasancelebi-Basoren areas

    Sectors Analysis of export led growth hypothesis in Turkey

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    Bu çalışma, Türkiye ekonomisi için “İhracata Dayalı Büyüme Hipotezi”nin geçerliliğini Toda-Yamamoto nedensellik yaklaşımını kullanılarak sektörler itibariyle, 2002Q1-2018Q4 dönemi için test etmeyi amaçlamaktadır. Toda-Yamamoto nedensellik testi sonuçlarına göre, Türkiye imalat sektörü için büyümeye dayalı ihracat hipotezinin geçerli olduğu, tarım, orman ve hayvancılık sektörü için ihracata dayalı büyüme hipotezinin geçerli olduğu tespit edilirken, hizmet sektörü için ise nedensellik ilişkisi tespit edilememiştir. Toplam ihracat ile GSYH arasındaki nedensellik ilişkinin ise çift yönlü olduğu görülmektedir.In this study, ‘Export-Led Growth Hypothesis’ is tested on the sectoral basis by applying Toda-Yamamoto causality approach in Turkey for the 2002Q1-2018Q4 period. The Toda-Yamamoto causality test results support the hypothesis of growth-led exports in the manufacturing sector and the hypothesis of export-led growth in the Agriculture, forestry and fishing sector. The results also indicate no causal relationship in the services sector. The causal relationship between total exports and GDP seems to be bidirectional

    Sectors analysis of export led growth gypothesis in Turkey

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    Bu çalışma, Türkiye ekonomisi için “İhracata Dayalı Büyüme Hipotezi”nin geçerliliğini Toda-Yamamoto nedensellik yaklaşımını kullanılarak sektörler itibariyle, 2002Q1-2018Q4 dönemi için test etmeyi amaçlamaktadır. Toda-Yamamoto nedensellik testi sonuçlarına göre, Türkiye imalat sektörü için büyümeye dayalı ihracat hipotezinin geçerli olduğu, tarım, orman ve hayvancılık sektörü için ihracata dayalı büyüme hipotezinin geçerli olduğu tespit edilirken, hizmet sektörü için ise nedensellik ilişkisi tespit edilememiştir. Toplam ihracat ile GSYH arasındaki nedensellik ilişkinin ise çift yönlü olduğu görülmektedir.In this study, ‘Export-Led Growth Hypothesis’ is tested on the sectoral basis by applying Toda-Yamamoto causality approach in Turkey for the 2002Q1-2018Q4 period. The Toda-Yamamoto causality test results support the hypothesis of growth-led exports in the manufacturing sector and the hypothesis of export-led growth in the Agriculture, forestry and fishing sector. The results also indicate no causal relationship in the services sector. The causal relationship between total exports and GDP seems to be bidirectional
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