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dc.contributor.authorKarsli, Orhan
dc.contributor.authorDokuz, Abdurrahman
dc.contributor.authorKaliwoda, Melanie
dc.contributor.authorUysal, Ibrahim
dc.contributor.authorAydin, Faruk
dc.contributor.authorKandemir, Raif
dc.contributor.authorFehr, Karl-Thomas
dc.description.abstractThe Eastern Pontides in NE Turkey is one of the major orogenic belts in Anatolia. In this paper, we report our new Ar-40/Ar-39 dating, mineral chemistry, major and trace elements and Sr-Nd-Pb isotopic analyses of the lamprophyre intrusions in this region. The lamprophyres are widely scattered and intrude Late Carboniferous granitoid rocks. The lamprophyres exhibit fine-grained textures and are mineralogically uniform. Hornblende Ar-40/Ar-39 dating yielded a plateau age of 216.01 +/- 10.64 Ma. Based on their geochemistry, mineral compositions and paragenesis, the lamprophyres are classified as calc-alkaline lamprophyres in general and spessartites in particular, which are rich in large ion lithophile elements (e.g., Rb, Ba, K) but depleted in Nb and Ti. Our samples exhibit moderate fractionation in LREE patterns approximately 100 times that of chondrite but HREE abundances less than 10 times that of chondrite. These calc-alkaline lamprophyres display a range of I-Sr (216 Ma) values from 0.70619 to 0.71291 and epsilon(Nd) (216 Ma) values from -1.4 to 4.1, with T-DM = 1.11 to 2.20 Ga. Their Pb isotopic ratios indicate an enriched mantle source. The enrichment process is related to metasomatism of a subcontinental lithospheric mantle source, which is caused by a large quantity of H2O-rich fluids, rather than sediments released from oceanic crust at depth during the closure of the Paleotethys Ocean in Triassic times. All of the geochemical data and the trace element modeling suggest that the primary magma of the calc-alkaline to high-K calc-alkaline spessartites was generated at depth by a low degree of partial melting (similar to 1-10%) of a previously enriched lithospheric mantle wedge consisting of phlogopite-bearing spinel peridotite. The ascendance of a hot asthenosphere triggered by extensional events caused partial melting of mantle material. The rising melts were accompanied by fractional crystallization and crustal contamination en route to the surface. All of the geochemical features combined with regional data suggest that the Eastern Pontides calc-alkaline lamprophyres originated in an extensional environment along an active continental margin throughout the Late Triassic. Such an extensional event, causing upwelling of hot asthenosphere, led to the opening of the northern branch of the Neotethys as a back-arc basin farther south of the Eastern Pontides. (C) 2014 Elsevier B.V. All rights reserved.en_US
dc.description.sponsorshipScientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [108Y200]en_US
dc.description.sponsorshipWe are most grateful to the staff of the Isotopic Laboratory of the Institute of Geology, Chinese Academy of Geological Sciences, in Beijing. This study was partly supported by the Scientific and Technological Research Council of Turkey (TUBITAK) with grant # 108Y200. Special thanks go to E. Yalcin Ersoy for the geochemical modeling. Thanks are due to Andrew Kerr for his editorial handlings and two anonymous reviewers for their accurate and constructive reviews.en_US
dc.publisherElsevier Science Bven_US
dc.subjectCalc-alkaline lamprophyresen_US
dc.subjectSubcontinental lithospheric mantleen_US
dc.subjectMantle meltingen_US
dc.subjectLate Triassic subductionen_US
dc.subjectBack-arc extensionen_US
dc.subjectEastern Pontidesen_US
dc.subjectNE Turkeyen_US
dc.titleGeochemical fingerprints of Late Triassic calc-alkaline lamprophyres from the Eastern Pontides, NE Turkey: A key to understanding lamprophyre formation in a subduction-related environmenten_US
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanıen_US
dc.departmentGümüşhane Üniversitesien_US
dc.authoridUysal, Ibrahim / 0000-0001-7607-2893
dc.authoridKANDEMIR, RAIF / 0000-0002-0344-9159
dc.authorwosidUysal, Ibrahim / AAE-3044-2019
dc.authorwosidAydin, Faruk / AAG-5614-2019

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