Petrogenesis of the Neogene alkaline volcanics with implications for post-collisional lithospheric thinning of the Eastern Pontides, NE Turkey

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dc.contributor.authorAydin, Faruk
dc.contributor.authorKarsli, Orhan
dc.contributor.authorChen, Bin
dc.date.accessioned2019-08-01T13:38:39Z
dc.date.available2019-08-01T13:38:39Z
dc.date.issued2008
dc.departmentNiğde ÖHÜ
dc.description.abstractWhole-rock geochemistry, Sr-Nd-Pb isotopes and K-Ar data are reported for alkaline samples collected from the Neogene alkaline volcanics (NAVs) in the Eastern Pontides, northeastern Turkey, in order to investigate their source and petrogenesis and geodynamic evaluation of the region. The NAVs were made of three groups that comprise of basanite-tephrite (feldspar-free; Group A), tephrite-tephriphonolite (feldspar and feldspathoid-bearing; Group B) and alkaline basalt-rhyolite (feldspathoid-free, Group C) series. These rocks cover a broad compositional range from silica-undersaturated to silica-oversaturated types, almost all of which are potassic in character. They show enrichment of LREE and LILE and depletion of HFSE, without a Eu anomaly in most of the mafic, samples. Textural features and calculated pressures based on the Cpx-barometer in each series indicate that the alkaline magma equilibrated at shallow crustal depths under a pressure of about 3-4.5 kbar and approximating a crystallization depth of 9-14 km. The NAVs are slightly depleted in isotopic composition, with respect to Sr-87/Sr-86 (ranging from 0.705018 to 0.705643) and Nd-143/Nd-144 (ranging from 0.512662 to 0.512714) that indicate young Nd model ages (0.51-059 Ga). This may indicate that the parent melts tapped a homogeneous and young lithospheric mantle source which was metasomatized by subduction-derived sediments during the Late Mesozoic. Pb isotopic compositions (Pb-206/Pb-204=18.85-18.95; Pb-207/Pb-204=15.60-15.74; Pb-208/Pb-204=38.82-39.25) may also be consistent with a model for an enriched subcontinental lithospheric mantle source. Lithospheric thinning and resultant upwelling of asthenosphere induced by lithospheric delamination may have favoured partial melting of chemically enriched, Young lithospheric mantle beneath the Eastern Pontides. Then, the melt subsequently underwent a fractional crystallization process along with or without minor amounts of crustal assimilation, generating a wide variety of rock types in a post-collision extensional regime in the Eastern Pontides during the Neogene. (C) 2008 Elsevier B.V. All rights reserved.
dc.description.sponsorshipResearch Foundation of Karadeniz Technical University from Trabzon, NE-Turkey; DAAD
dc.description.sponsorshipThis work was partly supported by the Research Foundation of Karadeniz Technical University from Trabzon, NE-Turkey. Sincere thanks are due to the DAAD for scholarship to Faruk Aydin. We thank Rainer Altherr and Hans-Peter Meyer in providing the microprobe analyses at Mineralogy and Petrology Institute, Heidelberg. We are grateful to M. Burhan Sadiklar for logistic support. Many thanks are given to Ismet Gedik and Abdurrahman Dokuz for their comments on the geodynamic modeling of this study. Raif Kandemir is thanked for his never-ending assistance during some figure designs. Special thanks are due to G. Pe-Piper and M.F.J. Flower for their useful suggestions and comments which considerably improved the manuscript. O. Cakir edited the English of the final text. Editorial comments by N. Eby are also acknowledged.
dc.identifier.doi10.1016/j.lithos.2007.12.010
dc.identifier.endpage266
dc.identifier.issn0024-4937
dc.identifier.issue45383
dc.identifier.scopus2-s2.0-49449102639
dc.identifier.scopusqualityQ1
dc.identifier.startpage249
dc.identifier.urihttps://dx.doi.org/10.1016/j.lithos.2007.12.010
dc.identifier.urihttps://hdl.handle.net/11480/5216
dc.identifier.volume104
dc.identifier.wosWOS:000259667400016
dc.identifier.wosqualityQ1
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.institutionauthor[0-Belirlenecek]
dc.language.isoen
dc.publisherELSEVIER SCIENCE BV
dc.relation.ispartofLITHOS
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanı
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.subjectNortheastern Turkey
dc.subjectalkaline volcanics
dc.subjectfractional crystallization
dc.subjectSr-Nd-Pb isotopes
dc.subjectenriched lithospheric mantle
dc.titlePetrogenesis of the Neogene alkaline volcanics with implications for post-collisional lithospheric thinning of the Eastern Pontides, NE Turkey
dc.typeArticle

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