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Abstract:

The relationship between small-scale topographic features and tectonic response of orogenic belts is often neglected due to scale differences in topographic data. Using Aster GDEM2, we calculated swath elevation, 200m topographic relief, and average slope angle of a small-scale watershed in the middle Himalayan orogen. Based on the geological history of Gyirong and data on the Himalayan uplift process, this study analyzed the topographic characteristics of Gyirong watershed, discussed the relationships between landform and structure, lithology, and climate, and compared slope stability. The results showed that the topographic elevation characteristics retained correspondence to local basement forms and tectonic associations. Periodic spatial change at the summit level had a clear response to the structural distribution, and may support the theory that the Gyirong basin floor is a combination of normal and reverse faults. Average height increased at first and then stabilized, and these morphological characteristics and distribution patterns provide topographic evidence for the interpretation of tectonic uplift and erosional accumulation, which confirmed that 4000m was the vertical differentiation boundary for the tectonic landform. Although climate, landforms, tectonics, and lithology vary across different orogenic belts, the similar slope angle threshold provided the insight that erosion is the tectonic genesis to equilibrium of heterogeneous hillsides at different scales.