- 1Department of Environmental Engineering, Marmara University, Istanbul, Türkiye (kamil.erkan@marmara.edu.tr)
- 2Department of Earth & Environmental Sciences, University of Minnesota, Minneapolis, MN, USA
- 3School of Geosciences, University of Sydney, Sydney, NSW, Australia
The Menderes Massif in western Anatolia is a large metamorphic core complex that formed in the back arc of the Aegean subduction zone. Geological and geodetic studies show that extension has occurred almost uniformly since the cessation of continental collision at c. 30 Ma. In this study, we used 2D numerical modeling informed by measurements of abundances of radioactive heat producing elements in exhumed Menderes metamorphic rocks (gneiss, schist, migmatite, granite) to investigate the effect of variation in vertical distribution of crustal radioactivity on the style of extensional deformation during core complex evolution. We assumed four different scenarios with the same total crustal radioactive heat production but fractionated differently between the upper and lower crust: 0%, 25%, 50%, and 62.5% of the total crustal radioactivity located within the thickened lower crust. Our numerical experiments reveal that lower crustal radioactivity has a major effect on the temperature (T) of the lower crust and hence its geodynamic evolution. We observed significant partial melting and core complex development only in the scenarios with fractions of 50% or more. The results are nearly independent of upper crustal radioactivity. The elevated radioactivity levels and therefore T of the lower crust drives partial melting, which in turn results in lower viscosity and enhanced crustal flow. According to these results, the lower part of the thickened orogenic crust in western Anatolia must be highly radiogenic in order for the formation of the observed core complex structure.
How to cite: Erkan, K., Whitney, D. L., and Rey, P. F.: Effect of variation in the vertical distribution of crustal radioactivity in metamorphic core complex development (Menderes Massif, Türkiye), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16582, https://doi.org/10.5194/egusphere-egu25-16582, 2025.