Quantifying the coupling effects of tectonics, climate, and lithology on the main drainage divide of a mountain belt

The formation and evolution of the main drainage divide (MDD) of mountain belts are of great significance in Earth's system as they control water allocation and species exchange. Extensive research has focused on deciphering the controlling factors (including vertical and horizontal tectonic movements, climate, and lithology) of MDD morphologies. However, a persistent limitation is the predominant focus on analyzing these controlling factors in isolation or in parts. Here, we develop a comprehensive equation for the steady-state position of MDD, which integrates all the tectonic and non-tectonic factors examined in previous work. We further conduct numerical simulations to verify the robustness of this equation. Additionally, based on the equation, we design an interactive program that allows users to predict an MDD's stable position under the set parameters. We also apply the equation to two natural examples to demonstrate its utility. This study will facilitate not only a deeper understanding of the evolution mechanism of the Earth’s surface but also the reconstruction of tectonic and/or climatic processes from mountain belt morphology.