STRUCTURAL EVOLUTION OF THE KAYABUKU SHEAR ZONE, SW TURKEY

The south-dipping Kayabuku (Selimiye) shear zone is located in the southern Menderes massif of the Western Anatolia Extended Terrane. It separates highly deformed metamorphic rocks composed of orthogneiss and augengneiss in its footwall from schist and marble rock units in its hanging wall. The schist unit is composed of garnet mica schist, chloritoid schist, quartz mica schist, quartzite, calcschist. The shear zone contains well-developed mesoscopic and microscopic shear sense indicators, especially within the augengneiss. A south-dipping normal fault is locally present between the schist and marble units on the hanging wall of the shear zone.

We have conducted a detailed field work along the shear zone between the towns of Milas and Yatagan in a strip that is 44 kms long and 3 kms wide. We also made systematic measurements of shear sense indicators along 7 geo-transects and collected 51 oriented rock samples from different lithologies and outcrops for microtectonic and petrographic studies. The average attitude of the foliation planes within the shear zone is measured as 274°/50°S with a NNE-SSW trending mineral lineation which is parallel to direction of the extension. The samples contain several shear sense indicators. Our field observations and preliminary microtectonic studies suggest that the shear zone shows two different sense of shearing; 1) top to the north and 2) top to the south which overprinted the former one. Therefore we suggest that the rocks within the shear zone have been subjected to at least two different deformation phases.