Landscape evolution and exhumation history during active continental extension: the central Menderes Massif, western Turkey
Final Report Abstract
The work undertaken in this project has advanced our understanding of the tectonic and landscape evolution of a bivergent metamorphic core complex in a region of active continental extension. The central Menderes Massif in western Turkey consists of two eastwest trending mountain ranges (the Bozdag and Aydin ranges), which are bounded by the Gediz detachment fault in the north and the Büyük Menderes detachment fault in the south, respectively. Our low-temperature thermochronological results and thermo-kinematic modelling reveal that rates of rock exhumation in different parts of the central Menderes Massif vary from 200–400 to 600–1100 m/Myr, respectively. The highest exhumation rates are associated with slip on the Gediz detachment, which is characterized by resistant cataclasites and mylonitic quartzites underneath. Here, erosion proceeds at rather low rates of 40-150 m/Myr and contributes only ~10% to rock exhumation. In contrast, erosional denudation in the footwall of the Büyük Menderes detachment and in the other parts of the massif is significantly higher (~150 to ~400 m/Myr). These higher rates are caused by the presence of weak and easily erodible lithologies such as mica schists and phyllites. Hence, erosion in these areas accounts for about 40–50 % of the total rock exhumation. The two studied detachment faults were active diachronously between ~22 Ma and ~3 Ma, as shown by the cooling histories of the rocks in their footwall and by K-Ar dating of illite from fault gouges. Extension and normal faulting started at the Büyük Menderes detachment, which experienced two phases of faulting between ~22 and ~13 Ma and from ~9 to ~3 Ma. Slip on the Gediz detachment fault started in mid-Miocene time (~15 Ma) and proceeded until the latest Pliocene (3–2 Ma). Most of our local 10Be erosion rates for ridge crests fall in the narrow interval of 50–90 m/Myr. The consistency of these local erosion rates across the central Menderes Massif shows that the amalgamation of a large number of bedrock clasts yields robust and representative erosion rates. As the erosion rates for ridge crests are generally lower than the erosion rates obtained for the neighbouring catchments, our combined set of erosion rates indicates that topographic relief in most parts of the central Menderes Massif is growing (except in the western Bozdag range). This increase in local relief is attributed to the ongoing north-south extension and rock uplift in the footwall of the major graben-bounding faults of the Gediz and Büyük Menderes grabens.
Publications
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(2017). Constraints on water reservoir lifetimes from catchment-wide 10Be erosion rates – a case study from Western Turkey. Water Resources Research 53, 9206–9224
Heineke, C., Hetzel, R., Akal, C., Christl, M.
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(2017). Late Cenozoic cooling history of the central Menderes Massif: timing and slip rate of the Büyük Menderes detachment and the relative contribution of normal faulting and erosion to rock exhumation. Tectonophysics 717, 585–598
Wölfler, A., Glotzbach, C., Heineke, C., Nilius, N.-P., Hetzel, R., Hampel, A., Akal, C., Dunkl, I., Christl, M.
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(2019). Detachment faulting in a bivergent core complex constrained by fault gouge dating and low-temperature thermochronology. Journal of Structural Geology 127
Heineke, C., Hetzel, R., Nilius, N.-P., Zwingmann, H., Todd, A., Mulch, A., Wölfler, A., Glotzbach, C., Akal, C., Dunkl, I., Raven, M., Hampel, A.
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(2019). Exhumation history of the Aydın range and the role of the Büyük Menderes detachment system during bivergent extension of the central Menderes Massif, western Turkey. Journal of the Geological Society of London 176, 704–726
Nilius, N.-P., Glotzbach, C., Wölfler, A., Hampel, A., Dunkl, I., Akal, C., Heineke, C., Hetzel, R.
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Spatial patterns of erosion and landscape evolution in a bivergent metamorphic core complex revealed by cosmogenic 10Be: The central Menderes Massif (Western Turkey). Geosphere 15
Heineke, C., Hetzel, R., Nilius, N.-P., Glotzbach, C., Akal, C., Christl, M., Hampel, A.
