Interactions of Tectonics and Rivers with the Surface of the Earth: Studies from Nepal, New Zealand's South Island, and the Naryn Basin, Kyrgyzstan

Both tectonic processes deforming the earth's lithosphere and erosion at the surface act to modify the landscape. Numerical modeling of bedrock rivers, interacting with ongoing surface deformation is an efficient way to learn what landforms may result from different combinations of erosional and tectonic processes. Exploration of a sophisticated model of bedrock channel erosion in concert with vertical rock uplift demonstrates that fluvial hanging valleys may form where the incision of bedrock tributaries is limited by a dearth of bedload tools to drive channel incision. Sporadic aggradation of sediment in the main stem can effectively reconnect hanging tributaries with the trunk stream. A simpler model of bedrock channel incision driven by stream power in concert with diverse surface deformation patterns indicates that the kinematics of fold growth at the surface may be recorded by the shape of channel incision profiles. I apply this new approach to Rough Ridge, one of the Otago Folds in New Zealand. The growth of folds and faults at the surface is commonly controlled by faults that extend deep into the crust. A unique combination of remote sensing, field work, and structural interpretation from the Naryn Basin, Kyrgyzstan, demonstrates how the weight of high topography may control the growth of structures within a low-lying basin. Finally, the deformation of river-cut terraces in the Naryn Basin constrains the timing of deformation across the western Naryn Basin.