Premium
Monsoonal hillslope processes determine grain size‐specific suspended sediment fluxes in a trans‐Himalayan river
Author(s) -
Struck Martin,
Andermann Christoff,
Hovius Niels,
Korup Oliver,
Turowski Jens M.,
Bista Raj,
Pandit Hari P.,
Dahal Ranjan K.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl063360
Subject(s) - sediment , geology , erosion , sedimentary budget , grain size , sedimentary rock , hydrology (agriculture) , fluvial , monsoon , orographic lift , sediment transport , geomorphology , geochemistry , oceanography , structural basin , precipitation , geography , geotechnical engineering , meteorology
Sediments in rivers record the dynamics of erosion processes. While bulk sediment fluxes are easily and routinely obtained, sediment caliber remains underexplored when inferring erosion mechanisms. Yet sediment grain size distributions may be the key to discriminating their origin. We have studied grain size‐specific suspended sediment fluxes in the Kali Gandaki, a major trans‐Himalayan river. Two strategically located gauging stations enable tracing of sediment caliber on either side of the Himalayan orographic barrier. The data show that fine sediment input into the northern headwaters is persistent, while coarse sediment comes from the High Himalayas during the summer monsoon. A temporally matching landslide inventory similarly indicates the prominence of monsoon‐driven hillslope mass wasting. Thus, mechanisms of sediment supply can leave strong traces in the fluvial caliber, which could project well beyond the mountain front and add to the variability of the sedimentary record of orogen erosion.