HR: 1340h
AN: H53D-0497    [Abstracts]
TI: A Comparison of Sediment Volumes Supplied to and Retained in Alluvial Fans of NE Owens Valley, California, USA
AU: * Verdeyen, M E
EM: m.verdeyen@alum.dartmouth.org
AF: Dartmouth College, 6105 Fairchild Hall, Hanover, NH 03755 United States
AU: Dade, W B
EM: brian.dade@dartmouth.edu
AF: Dartmouth College, 6105 Fairchild Hall, Hanover, NH 03755 United States
AU: Sonder, L
EM: leslie.sonder@dartmouth.edu
AF: Dartmouth College, 6105 Fairchild Hall, Hanover, NH 03755 United States
AB: Alluvial fans are useful settings for the study of the effects of tectonic, lithologic and climatic conditions on landscape evolution. Previous research in this regard has aimed to quantify the effects of environmental conditions on the plan geometric relationship between alluvial fans and their source catchments. This approach reflects the untested assumption that catchment-fan pairs are closed systems in which all sediment eroded from the catchment is retained in the fan. We compare the volume of sediment supplied to a fan, equated to the volume of a source canyon, with the volume of sediment retained in the fan, assessed with existing and newly acquired gravimetric and topographic surveys conducted across nine alluvial fan systems in northeastern Owens Valley, CA. On average, about 50 percent of the sediment supplied to the valley is apparently retained in the fans, but proximity to a local sink, in this study, Owens River, significantly influences the amount of sediment one accounted for in an individual alluvial fan deposit. In the extreme, fans closest to Owens River appear to retain only about 15 percent of material supplied to it. We speculate that fan deposits are either carried away by the river or buried under flood plain deposits. As a result of such processes, we conclude that the ratio of areas of fan and source catchment can vary systematically with proximity to a local sink. Such complications need to be considered in interpretations of fan-catchment geometry.
DE: 1824 Geomorphology: general (1625)
SC: Hydrology [H]
MN: Fall Meeting 2005