Decoupling of erosion and precipitation in the Himalayas

Published

Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Burbank, DW; Blythe, AE; Putkonen, J; Pratt-Sitaula, B; Gabet, E; Oskin, M; Barros, A; Ojha, TP

Published Date

  • December 11, 2003

Published In

Volume / Issue

  • 426 / 6967

Start / End Page

  • 652 - 655

International Standard Serial Number (ISSN)

  • 0028-0836

Digital Object Identifier (DOI)

  • 10.1038/nature02187

Citation Source

  • Scopus