SOUTHERN MENDERES MASSIF - AN INCIPIENT METAMORPHIC CORE COMPLEX IN WESTERN ANATOLIA, TURKEY

In the southern sector of the Menderes Massif, north of Selimiye (Mila s) augen gneisses interpreted as a deformed peraluminous granite have been dynamothermally metamorphosed and are surrounded by and intrude a regionally metamorphosed Palaeozoic 'envelope'. The granitic rocks ex hibit a moderately-dipping mylonitic foliation and NNE-SSW- trending m ineral elongation lineation. The progressive deformation of the granit ic rocks produces a structural sequence typical of an extensional shea r zone marked, from bottom to top, by a very thick extensive zone of m ylonites followed in turn by brecciated mylonite and cataclasite. The kinematic indicators exhibit a top-to-the south, down-dip sense of she ar. These structures are attributed to exhumation of the granitic rock s of the massif along a major, south-dipping, normal-sense shear zone that accommodated crustal extension during Late Oligocene collapse of the orogen in western Turkey. Thus, the southern Menderes Massif may b e interpreted as the exhumed footwall of a major extensional shear zon e, and possibly as an incipient core complex.