『Abstract
The relationships between climate, topography, and erosion are
significant in understanding landscape evolution. In order to
study this relationship in a tectonically active landscape, the
details of 11 drainage basins were collected from Qilian Shan
Mountains. Decadal-scale erosion rates, including the mechanical
load and solute load contributions, are estimated in natural conditions.
The calculated erosion rates show that the average erosion rate
of Qilian Shan Mountains is about 0.08 mm/yr, while the variation
of annual erosion rates within each basin is significant. The
changes of topography and climate, which potentially control erosion
rates, are also employed in this paper for correlating analyses.
Correlation analyses indicate that erosion rates are more closely
correlated with topographic variables, such as mean local relief
and mean slope, than all of the climatic variables; and mean local
relief and decadal-scale erosion rates show a linear relationship
in these tectonically active mountains. However, some topographic
variables like basin area and elongation ratio exert limited influence
on erosion rates; while others, such as basin elevation, basin
relief and basin roughness, show poor correlation. The results
indicate that topographic control, like aspects of the local terrain
steepness, plays the most important role in spatial distribution
of decadal-scale erosion rates throughout Qilian Shan Mountains.
Under topographic control, some climatic variables, like discharge
and runoff, however, could account for the significant variation
of annual erosion rates are lower than the long-term river incision
rates, as well as the exhumation rates during early and middle
Miocene. The change to more arid climatic condition since the
middle Miocene combining with tectonic uplift should attribute
to the inconsistent erosion rates over different timescales in
Qilian Shan Mountains.
Keywords: Qilian Shan Mountains; erosion; mean local relief; topography;
climate』
1. Introduction
2. Geologic and geographic setting
3. Materials and methods
3.1. Erosion rates
3.2. Potential variables controlling erosion
4. Results and discussion
4.1. Potential controls on erosion rates
4.2. Decadal erosion rates versus long-term erosion rates
5. Conclusion
Acknowledgements
Appendix A. Supplementary data
References