Decoupling of erosion and precipitation in the Himalayas

Abstract

The hypothesis that abrupt spatial gradients in erosion can cause high strain rates in active orogens has been supported by numerical models that couple erosional processes with lithospheric deformation via gravitational feedbacks. Most such models invoke a 'stream-power' rule, in which either increased discharge or steeper channel slopes cause higher erosion rates. Spatial variations in precipitation and slopes are therefore predicted to correlate with gradients in both erosion rates and crustal strain. Here we combine observations from a meteorological network across the Greater Himalaya, Nepal, along with estimates of erosion rates at geologic timescales (greater than 100,000 yr) from low-temperature thermochronometry. Across a zone of about 20 km length spanning the Himalayan crest and encompassing a more than fivefold difference in monsoon precipitation, significant spatial variations in geologic erosion rates are not detectable. Decreased rainfall is not balanced by steeper channels. Instead, additional factors that influence river incision rates, such as channel width and sediment concentrations, must compensate for decreasing precipitation. Overall, spatially constant erosion is a response to uniform, upward tectonic transport of Greater Himalayan rock above a crustal ramp.

Three‐dimensional numerical models with varied material properties and erosion rates: Implications for the mechanics and kinematics of compressive wedges

“…The high erosion rates maintain material removal and deformation along the Alpine Fault [Koons, 1990;Beaumont et al, 1992]. Many recent studies also suggest that focused erosion along the Himalayan front also may have an effect on the nature and locus of the deformation [e.g., Thiede et al, 2004Thiede et al, , 2005Wobus et al, 2003Wobus et al, , 2005, although other authors argue against erosion playing such as controlling role [e.g., Burbank et al, 2003].…”

Digital Elevation Model Differencing and Error Estimation from Multiple Sources: A Case Study from the Meiyuan Shan Landslide in Taiwan

“…As a result, a profiling method that stack elevation values on parallel, equally-spaced tangents has been developed, i.e., the swath profile method. Applications of the swath profile method can often be found in the analysis of large-scale regional terrain issues, such as tectonic structures or landslides [44][45][46].…”

Late Miocene provenance change on the eastern margin of the Yinggehai-Song Hong Basin, South China Sea: Evidence from U–Pb dating and Hf isotope analyses of detrital zircons

“…The provenance change is consistent with the broad climate change in the Late Miocene (Harrison et al, 1992;Molnar et al, 1993), which was affected significantly by increases in altitude of the plateau . Erosion patterns in southeastern Asia may have been related to rock uplift rates, but are presently not climatically controlled (Burbank et al, 2003;Hoang et al, 2009). Wan et al (2007) used a multi-proxy approach to reconstruct the past change of the East Asian monsoon since 20 Ma.…”