Generation of the Early Cenozoic adakitic volcanism by partial melting of mafic lower crust, Eastern Turkey: Implications for crustal thickening to delamination

Basit Öğe Kaydı
dc.authorid0000-0002-8091-1239
dc.contributor.authorKarsli, Orhan
dc.contributor.authorDokuz, Abdurrahman
dc.contributor.authorUysal, Ibrahim
dc.contributor.authorAydin, Faruk
dc.contributor.authorKandemir, Raif
dc.contributor.authorWijbrans, Jan
dc.date.accessioned2019-08-01T13:38:39Z
dc.date.available2019-08-01T13:38:39Z
dc.date.issued2010
dc.departmentNiğde ÖHÜ
dc.description.abstractEarly Cenozoic (48-50 Ma) adakitic volcanic rocks from the Eastern Pontides NE Turkey consist of calc-alkaline and high-K calc-alkaline andesite and dacite, with SiO(2) contents ranging from 56 01 to 65 44 wt.%.. This is the first time that Early Eocene volcanism and adakites have been reported from the region. The rocks are composed of plagioclase, amphibole, quartz, and Mg-rich biotite. They have high and low-Mg# values ranging from 55 to 62 and 13 to 42. respectively. High-Mg# rocks have higher Ni and Co contents than low-Mg# samples. The rocks exhibit enrichments in large ion lithophile elements including the light rare earth elements, depletions in Nb, Ta and Ti and have high La/Yb and Sr/Y ratios. Their relative high I(Sr) (0.70474-0.70640) and low epsilon(Nd) (50 Ma) values (-2.3 to 0.8) are inconsistent with an origin as partial melts of a subducted oceanic slab. Combined major- and trace element and Sr-Nd isotope data suggest that the adakitic magmas are related to the unique tectonic setting of this region, where a transition from a collision to an extension stage has created thickening and delamination of the Pontide mafic lower crust at 50 Ma The. high-Mg adakitic magmas resulted from partial melting of the delaminated eclogitic mafic lower crust that sank into the relatively hot subcrustal mantle, and its subsequent interaction with the mantle peridotite during upward transport, leaving garnet as the residual phase, elevates the MgO content and Mg# of the magmas, whereas low-Mg# magmas formed by the melting of newly exposed lower crustal rocks caused by asthenospheric upwelling, which supplies heat flux to the lower crust. The data also suggest that the mafic lower continental crust beneath the region was thickened between the Late Cretaceous and the Late Paleocene and delaminated during Late Paleocene to Early Eocene time, which coincides with the initial stage of crustal thinning caused by crustal extensional events in the Eastern Pontides and rules out the possibility of an extensional regime before similar to 50 Ma in the region during the Late Mesozoic to Early Cenozoic. (C) 2009 Elsevier B.V. All rights reserved.
dc.description.sponsorshipScientific and Technological Research Council of Turkey (TUBITAK) [107Y177]
dc.description.sponsorshipFinancial support of this work was provided by the Scientific and Technological Research Council of Turkey (TUBITAK) with grant# 107Y177. We thank Bin Chen for the Sr-Nd isotopic analyses and Ahmet D. Sen and Murat Ketenci for their assistance with the fieldwork. Special thanks are due to Murat Erduran for his useful comments on an early version of this manuscript. We thank the editor, Professor Nelson Eby, and Pat Castillo and an anonymous reviewer for their constructive reviews.
dc.identifier.doi10.1016/j.lithos.2009.08.003
dc.identifier.endpage120
dc.identifier.issn0024-4937
dc.identifier.issue45323
dc.identifier.scopus2-s2.0-71649088766
dc.identifier.scopusqualityQ1
dc.identifier.startpage109
dc.identifier.urihttps://dx.doi.org/10.1016/j.lithos.2009.08.003
dc.identifier.urihttps://hdl.handle.net/11480/4966
dc.identifier.volume114
dc.identifier.wosWOS:000274378300008
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.publicationcategoryDiğer
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.subjectSr-Nd isotopes
dc.subjectAdakites
dc.subjectAndesite and dacite
dc.subjectDelaminated mafic lower crust
dc.subjectEarly Eocene volcanism
dc.subjectEastern Pontides
dc.subjectNE Turkey
dc.titleGeneration of the Early Cenozoic adakitic volcanism by partial melting of mafic lower crust, Eastern Turkey: Implications for crustal thickening to delamination
dc.typeReview Article

Dosyalar

Koleksiyon

WoS İndeksli Yayınlar Koleksiyonu
Scopus İndeksli Yayınlar Koleksiyonu