Structural Evolution of the Kayabuku Shear Zone, Southern Menderes Massif, Western Turkey

Abstract

This study is concerned with the geologic evolution of the Kayabuku (Selimiye) shear zone, Menderes Massif, Turkey. A geologic map between the towns of Milas and Yatagan was compiled from 1:25,000 scale previous geologic maps. 7 transects were made along the shear zone and 51 oriented rock samples were collected for microtectonic and petrographic analysis. Mesoscopic shear sense indicators were examined in the field. The Kayabuku shear zone separates orthogneiss in its footwall from schist and marble in its hanging wall. The first developed ductile shearing is top-to-the north, overprinted by top-to-the south ductile shearing which, in turn, is overprinted by top-to-the south brittle deformation. The hanging wall of the shear zone is locally brittlely deformed by a south-dipping normal fault zone, discontinuously exposed between the schist and marble units. Therefore, the shear zone must have been subjected to at least two deformation phases; D1: top-to-the north and D2: top-to-the south.