Coupling of tectonics, climate, and lithology in orogenic systems. Insights from cosmogenic 10Be erosion rates and river profile inversion modeling in the Talesh Mountains, NW Iranian Plateau

The landscape of the Talesh Mountains, located in the NW sector of the Iranian Plateau (within the Arabia-Eurasia collision zone), results from the interplay of multiple forces. To explore the interaction between tectonics, climate, and lithology we present 11 new erosion rates derived from meteoric 10Be on the eastern (wetter) and western (drier) flanks of the range. The erosion rates range from approximately 100 to 400 m/Myr, with lower values in the more arid plateau interior and higher values in the more humid plateau exterior (western and eastern Talesh flanks, respectively). These rates exhibit a positive correlation with topographic metrics and a moderate correlation with mean annual precipitation, suggesting a tectonic control possibly enhanced by the across-strike precipitation gradient. Conversely, erosion rates do not correlate with rock strength. However, along- and across-strike changes in rock erodibility suggest that lithology may have influenced the landscape response time to evolving boundary conditions. Furthermore, relative rock-uplift histories from river profile inversion analysis indicate that mountain-building processes accelerated around 12–10 Ma, possibly due to a combination of short-wavelength (i.e., shallower) processes, such as thrusting, and long-wavelength (i.e., deeper) processes, such as lower mantle inflow. This led to a progressive precipitation concentration along the windward side of the orogen, leading to efficient mass removal via erosion and further enhancing tectonic activity. Additionally, an increase in erosion rates occurred during the 0.6–1.5 km lowering of the Caspian Sea base-level between ∼6 and 3.2 Ma. Overall, the efficient erosion on the wetter side likely concentrated tectonic deformation, ultimately contributing to the development of a stationary wedge.