Correlating uplift rate and river erosion rate using channel modelling in southwest Qinghai Tibet Plateau

Abstract

Bedrock uplift rate is one of the most fundamental quantities in the field of orogen studies, as it has the utility for quantifying large-scale tectonic forces. Recent studies have provided evidence that the river incision rate exerts significant impact on controlling the bedrock uplift rate. Detachment limited stream power model is one of the most well-known river erosion models, which uses the balanced longitudinal channel profile and introduces the channel steepness index to extract the correlation between bedrock uplift rate and river erosion rate. The southwest of Qinghai Tibet Plateau, adjacent to the Himalayas, is the region with the strongest interaction between global tectonics and climate, The high mountains and peaks disturb the local atmospheric circulation, which will react with erosion and tectonic activities. Therefore, this region is an ideal natural laboratory to study the coupling between tectonics and climate and its impact on geomorphology, which will also help for understanding the uplift mechanism and quantifying mountain building forces of entire Qinghai Tibet Plateau. In this study, the 30m-90m spatial resolution digital elevation dataset “SRTM” are utilized to extract the river profile, using ArcGIS and Matlab software to calculate Steepness Index value, and then revised the correlation of the uplift rate and erosion rate. Our results show that the river steepness index can effectively quantify the uplift rate. There is a significant positive correlation between the uplift rate and erosion rate along the active fault zone in the study area, and fault activity may be an important controlling factor affecting the correlation between them.