A demonstration of the importance of bedload transport for fluvial bedrock erosion and knickpoint propagation

Auteur(s) et Affiliation(s)

COOK, K.L.

Dept. of Geosciences, National Taiwan Univ., Taipei, Taiwan, Province de Chine

TUROWSKI, J.M.

Swiss Federal Research Inst. WSL, Birmensdorf, Suisse

HOVIUS, N.

Dept. of Earth Sciences, Univ., Cambridge, Royaume-Uni

Description :
Using aerial photographs, field surveys, and hydrological data, the AA. constrain the incision history of a bedrock gorge 1200 m long and up to 20 m deep cut by Da'an River in western Taiwan. This reach of the river experienced 10 m of uplift during the 1999 Chi-Chi earthquake. For 5 years following the earthquake, bedload was prevented from entering the uplift zone, the knickpoint was static and little incision took place. Bedload transport across the uplift zone resumed in 2004, initiating extremely rapid incision, with 620 m of knickpoint propagation and up to 20 m of downcutting by 2008. This change highlights the relative inefficiency of suspended sediment and the dominant role of bedload as a tool for fluvial erosion and knickpoint propagation. Knickpoint propagation was influenced by geological structure, lithology, and drainage organization. In particular, a change in dip of the sandstone beds at the site caused a decrease of knickpoint propagation velocity.

Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2013, vol. 38, n°. 7, p. 683-695, nombre de pages : 13, Références bibliographiques : 2 p.

Date :
2013

Editeur :
Pays édition : Royaume-Uni, Chichester, Wiley

Langue :
Anglais