- Turkish Journal of Earth Sciences
- Vol: 17 Issue: 3
- The Geochemistry and Setting of the Demirci Paragneisses of the Sünnice Massif, NW Turkey
The Geochemistry and Setting of the Demirci Paragneisses of the Sünnice Massif, NW Turkey
Authors : Erdinç Yiğitbaş, John A. Winchester & Christopher J. Ottley
Pages : 421-431
Doi:10.3906/sag-1205-49
View : 5 | Download : 2
Publication Date : 9999-12-31
Article Type : Makaleler
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 (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.Keywords : geochemistry, nappes, Proterozoic paragneiss, Sünnice Massif, Turkey