The Geochemistry and Setting of the Demirci Paragneisses of the Sünnice Massif, NW Turkey

Authors : Erdinç YİĞİTBAŞ, John A Winchester Christopher J OTTLEY

Pages : 421-431

Doi:10.3906/sag-1205-49

View : 16 | Download : 5

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The 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 insert ignore into journalissuearticles values(Çele meta-ophiolite);, deformed and subjected to amphibolite facies metamorphism before the emplacement of late Neoproterozoic metavolcanic rocks later subjected to greenschist-facies metamorphism insert ignore into journalissuearticles values(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.
Keywords : geochemistry, nappes, Proterozoic paragneiss, Sünnice Massif, Turkey