METAMORPHISM OF PRECAMBRIAN-PALAEOZOIC SCHISTS OF THE MENDERES CORE SERIES AND CONTACT RELATIONSHIPS WITH PROTEROZOIC ORTHOGNEISSES OF THE WESTERN ÇINE MASSIF, ANATOLIDE BELT, WESTERN TURKEY

Abstract

The tectonic setting of the southern Menderes Massif, part of the western Anatolide belt in western Turkey, is characterized by the exhumation of deeper crustal levels onto the upper crust during the Eocene. The lowermost tectonic units of the Menderes Massif are exposed in the Çine Massif, where Proterozoic basement orthogneisses of the Çine nappe are in tectonic contact with Palaeozoic metasedimentary rocks of the Selimiye nappe. In the southern Çine Massif, orthogneiss and metasedimentary rocks are separated by the southerly dipping Selimiye shear zone, preserving top-to-the-S shearing under greenschist facies conditions. In contrast, in the western Çine Massif, the orthogneiss is deformed and mylonitic near the contact with the metasedimentary rocks. The geometry of the mylonite zone and the observed shear directions change from north to southwest. In the north, the mylonite zone dips shallowly to the north, with top-to-the-N shear sense indicators showing northward thrusting of the orthogneiss over the metasedimentary rocks. In the southwest, the mylonite zone resembles a steep N–S striking strike-slip shear zone associated with top-to-the-SSW sense of shear. Overall, the geometry of the mylonite shear zone is consistent with northward movement of the orthogneiss relative to the metasedimentary rocks. Different shear senses are attributed to strain partitioning.