HR: 1340h
AN: H53C-1255    [Abstracts]
TI: Experimental Channel Response to Tectonic Uplift
AU: * Turowski, J M
EM: jmt43@esc.cam.ac.uk
AF: Department of Earth Sciences University of Cambridge, Downing Street, Cambridge, CB2 3EQ United Kingdom
AU: Lague, D
EM: dlag02@esc.cam.ac.uk
AF: Geosciences Rennes, UMR G118 CNRS, Campus de Beaulieu, Rennes Cedex, 35042 France
AU: Crave, A
EM: alain.crave@univ-rennes1.fr
AF: Geosciences Rennes, UMR G118 CNRS, Campus de Beaulieu, Rennes Cedex, 35042 France
AU: Hovius, N
EM: nhovius@esc.cam.ac.uk
AF: Department of Earth Sciences University of Cambridge, Downing Street, Cambridge, CB2 3EQ United Kingdom
AB: We performed a series of experiments to investigate the relationship between channel geometry and tectonic forcing in steady state landscapes at various uplift rates. The experiment consists of uniformly uplifted silica paste eroded by artificial rainfall. The landscape evolves by growth and amalgamation of incisions and organises into a drainage network. High precision (0.5mm pixel size) digital elevation models were taken by a stereometric camera system. Channel bed slope is found to be independent of discharge and position on the experimental surface and increases linearly with uplift rate. This suggests it is controlled by global conditions rather than local channel processes. Using hydraulic assumptions the channel parameters width, depth, cross-sectional area, wetted perimeter and hydraulic radius were derived. We find that the channel width, cross-sectional area and wetted perimeter decay exponentially with uplift rate. The hydraulic radius is approximately constant and the channel depth rises linearly with uplift rate. These results are qualitatively consistent with recent field surveys.
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting