How does climate affect the topography in tectonically active orogens

Abstract

AbstractA central theme in geomorphology is the quantitative determination of the relationship between topography and its controlling factors, such as tectonics, lithology, and climate. However, rather than relief and slope, channel steepness (ksn) is a more effective metric for topography, and together with the abundance of beryllium‐10 (10Be) erosion rate data, it provides a more convenient means of quantitatively revealing the relationship between topography and its driving factors. A power‐law relationship between ksn and 10Be erosion rates has been widely demonstrated, which indicates the dominant control of tectonics on topography, while the dominant control of climate has not been clearly revealed. In this study we selected nine tectonically active regions, comprising 241 catchments, covering a wide range of mean annual precipitation values, and by extracting ksn values and hypsometric curves, we obtained the relationship between ksn and erosion rates. The results show that the power‐law relationship differs between regions, largely due to differences in the erosion coefficient, K. After separating the influences of lithology and climate, we found that although soft sedimentary rocks will increase the erosion coefficient, precipitation plays the main role in controlling the erosion coefficient, resulting in a linear relationship between precipitation and K. This relationship clearly demonstrates the occurrence of higher relief under a drier climate, even with similar rates of tectonic uplift.