Polyphase deformation features and extensional detachment faults on the northern and southern edges of the Nigde Massif (Central Anatolia-Turkey)

Abstract

The polyphase deformation features and detachment faults on the northern (Gumusler) and southern (Camardı) borders of the Nigde Massif rocks, as well as the structures developed as a result of these faults, are investigated in this paper. The Nigde Massif in the studied areas is basement Palaeozoic–Mesozoic metamorphic units. The Late Cretaceous Uckapılı granodiorite and Sineksizyayla meta-gabbro introduced the Nigde massif. These units are overlain unconformably by Late Cretaceous-Quaternary rocks. The metamorphic rocks on the massif's southern edge underwent 5-phase ductile deformation, whereas the metamorphic rocks on the northern margin underwent 3-phase folding. Both the northern and southern edges include post-Middle Eocene extensional detachment features. These are most likely extensional detachment faults related to the massif's uplift. Central Anatolia is still under an extensional tectonic regime today. Therefore, detachment fault activity and occurrence continue. A large portion of the low-angle normal faults shows an extensional detachment feature. The detachment faults identified north and south of the study area are also active today.