Yi?itbaş, ErdinçWinchester, John A.Ottley, Christopher J.2025-01-272025-01-2720081303-619Xhttps://search.trdizin.gov.tr/tr/yayin/detay/79096https://hdl.handle.net/20.500.12428/13663The Demirci migmatitic quartzofeldspathic gneisses of the Sünnice Massif, exposed in the İstanbul Zone north of Bolu, have compositions that show them to be paragneisses, associated with subordinate para-amphibolites. They consist principally of metamorphosed, rather calcareous greywackes, with sediment derived from a continental arc source. They occur in the para-autochthon below a nappe pile (Çele meta-ophiolite), deformed and subjected to amphibolite facies metamorphism before the emplacement of late Neoproterozoic metavolcanic rocks later subjected to greenschist-facies metamorphism (Yellice volcanics). As they are overlain in sequence by nappes comprising sections of the Çele meta-ophiolite with ocean floor basalt and island arc tholeiite compositions respectively, the Demirci paragneisses may represent a section of the ancient continental basement on to which the meta-ophiolite was obducted during the Proterozoic. Copyright © TÜBİTAK.eninfo:eu-repo/semantics/closedAccessGeochemistry; Nappes; Proterozoic paragneiss; Sünnice Massif; TurkeyArticle1734214312-s2.0-5474908387479096Q2