Landscape evolution and exhumation history during active continental extension: the central Menderes Massif, western Turkey

• Applicants: Dr. Christoph Glotzbach; Professor Dr. Ralf Hetzel
• Subject Area: Palaeontology
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 266603677

In tectonically active regions, crustal deformation and surface processes act in concert to shape Earth's landscapes. To reconstruct the spatiotemporal evolution of the Earth's surface and to evaluate the impact of long-term and short-term processes on landscape evolution, quantifying the rates of faulting and surface processes across different time scales is inevitable. In the proposed project, we will investigate landscape evolution during continental extension, where exhumation of rocks does not only occur by erosion (as in regions undergoing crustal shortening) but also by normal faulting. To date, quantitative constraints on rates of landscape evolution in such actively extending regions is sparse and hence knowledge about the relative importance of the involved processes limited. In our project we will use cosmogenic nuclides and low-temperature thermochronology to unravel the landscape evolution across time scales in a key region of continental extension, the central Menderes Massif (western Turkey). In this part of the Aegean realm, ongoing bivergent extension since the Miocene has created a pronounced topographic asymmetry, with the shallow-dipping flanks of the massif being the geomorphological expression of detachment faults while steep escarpments are presumably dominated by high-angle normal faulting. The central Menderes Massif offers excellent outcrop conditions including well preserved detachment faults and ideal lithologies for applying both cosmogenic nuclides (10Be) and low-temperature thermochronology. Using 10Be, we will determine spatially averaged erosion rates for a broad spectrum of catchment morphologies. Our 10Be data will resolve how the fault-induced topographic asymmetry influences the Holocene erosion pattern. By comparing catchment-wide erosion rates with local erosion rates to be obtained from ridge crests, we will decipher if the relief in the central Menderes Massif is still growing. From apatite and zircon (U-Th)/He and fission track dating, we will obtain cooling ages that will be used to derive a) the slip rates of the two detachment faults framing the central Menderes Massif and b) the exhumation pattern and its hypothesized spatiotemporal variation. The thermochronological data will be analysed using advanced 3D thermokinematic modelling (software PECUBE), which will yield quantitative constraints on fault geometry and slip rates as well as on exhumation and erosion rates. By combining the results from both methods, we will provide a comprehensive synthesis of rock exhumation, normal faulting, and landscape development during continental extension. Ultimately, our results will advance the understanding of landscape evolution across time scales.

• DFG Programme: Research Grants
• Co-Investigators: Professorin Dr. Andrea Hampel; Dr. Andreas Wölfler