Late Neogene mountain building of eastern Kunlun orogen: Constrained by DEM analysis

Abstract

Topography, as a net result of the dynamic interaction between endogenesis and exogene- sis, holds immense information on tectonic uplift, surface erosion and thus mountain building. The eastern Kunlun (昆仑) orogen, which experienced significant Late Neogene tectonic uplift and is located in an arid environment, is advantageous for morphotectonic analysis based on well-preserved tectonic landforms. The digital elevation model (DEM) analysis was carried out for the central segment of the eastern Kunlun orogen based on shuttle radar topography mission (SRTM) data. River longitudinal profile analysis indicates that major rivers across the orogen are characterized by high river gradient indexes and intensive tectonic uplift. Differential uplift was also identified in swath-topography analysis in the studied area, which can be divided into three major tectonic-geomorphic units by orogenic- strike-parallel faults. It is indicated that the most active region is located to the south of the Xidatan (西 大滩) fault with significant differential uplift. Another identified fault with differential uplift is the Middle Kunlun fault; however, the timing of which is suggested to be much older than that of the Xidatan fault. These analyses are concordantly supported by both field survey and studies of thermo- chronology, which in turn indicates that the DEM analysis bears great potential in morphotectonic analysis.