How to constrain the uplift history and landscape evolution processes of the youthful stage mountain by the landscape evolution model?

Abstract

<p>Starting in the 1990s，geoscientists began to translate many geomorphic processes into computer program (landscape evolution models LEMs) to simulate the form and characteristics of Earth surface. How to correctly evaluate the similarity of simulated and realistic terrain is a main problem to verify the accuracy of reproducing the landscape evolution. In the process of landscape evolution, the landform experiences vertical variation and horizontal spatial topological structure variation. The lack of effective characteristic to compare the similarity of different topographies in two dimensions has been the major problem restricting the application of LEMs in geomorphic application. We speculate that the appropriate topographic characteristics group can measure the similarities of simulated and realistic terrain in two dimensions, and constrain its landscape evolution processes by LEMs. A region with a uniform climate and with well-defined geological and geomorphic processes is well suited to verify the foregoing speculation via numerical simulation. The arid region of North-West China (Hexi Corrdior and northern piedmont of the Chinese Tian Shan) has an arid climate with spatially uniform precipitation, and is subjected to relatively simple erosional processes. Moreover, there are many youthful stage mountains with obvious difference form and characteristics. which indicates that different tectonic activity is the main factor for their difference surfaces. First of all, we have analyzed difference topographic characteristics of four youthful stage mountains (the Jintanan Mt., Heli Mt. around Hexi Corrdior; the Manas Ant. Huoerguosi Ant. in northern piedmont of the Chinese Tian Shan) and simulated its evolution by Landlad. Then, with the topographic characteristics group (uniform valley spacing, local relief, outlet spacing), we compared the realistic and simulated terrain for different model ages. Finally, based on the similarity of the terrains, we estimated the timing of the initial uplift and the rock uplift rate of those mountains. The results are consistent with previous geological and geomorphological records from these youthful stage mountains. Our findings demonstrate that LEMs combined with topographic characteristics are a reliable means of constraining the timing of the initial uplift and the rock uplift rate of the youthful stage mountain. Our approach has the potential to be applied in other youthful stage mountains and to become widely-used tool in tectonic geomorphology.</p>