Links between tectonic processes and landscape morphology in an alpine collision zone, south-central Turkey

Diverse landforms in south-central Turkey developed in response to feedbacks among extensional tectonics, topography, climate, and erosion in a collisional orogen during the last 40 million years. The neotectonic evolution of south-central Turkey represents a classic example of collapse of tectonically thickned continental crust in an alpine-style collision zone. The current landscape is characterized by a peneplain surface containing narrow, curvilinear basins and an extensive volcanic field in the north. A rugged mountain chain in the south has a steep slope facing the peneplain surface to the north and a gentle slope towards the Mediterranean Sea in the south. Several episodes of collisional events during the Late Cretaceous and Early Tertiary were responsible for crustal thickening, high T/P metamorphism, and topographic build-up prior to the onset of the neotectonic phase in the region. Isostatic rebound of the partially subducted platform facilitated the uplift of deformed carbonates in the lower plate and the exhumation of thermally-weakened high-grade metamorphic rocks of the Nigde massif in the upper plate of the paleo-subduction zone. The uplift of the carbonate platform occurred in the footwall of a steeply north-dipping frontal fault zone during the Oligo-Miocene, and the exhumation of the Nigde metamorphic rocks occurred in the footwall of a detachment fault during the Miocene. Both the uplifted carbonate platform and the exhumed core complex underwent extensive fluvial denudation in the Oligo-Miocene. Widespread Plio-Pleistocene glaciation accelerated erosion rates which in turn increased the surficial uplift and surface topography of the mountains in response to isostatic compensation. Post-orogenic magmatism in the subsiding hinterland of the collision zone produced the Cappadocian Volcanic Province with bimodal volcanism and stratovolcanoes during Middle Miocene to Quaternary time. This magmatic pulse marks an advanced stage of the morphotectonic evolution of the collapsing orogen and was driven by further lithospheric extension and thinning.