Record Details
The role of rock resistance and rock uplift on topographic relief and river longitudinal profiles in the coastal mountains of Oregon and a landscape-scale test for steady-state conditions
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | The role of rock resistance and rock uplift on topographic relief and river longitudinal profiles in the coastal mountains of Oregon and a landscape-scale test for steady-state conditions |
| Names |
VanLaningham, Sam J.
(creator) Meigs, Andrew (advisor) |
| Date Issued | 2002-11-19 (iso8601) |
| Note | Graduation date: 2003 |
| Abstract | Analysis of topographic and river morphometric parameters was conducted using digital elevation models (DEMs) and field observations in order to determine the role of variable rock resistance on topographic relief, to examine how spatially and temporally variable rock uplift rates relate to river morphology, and to address the degree to which uplift and erosion are in steady-state in the actively uplifting region of the Coast Ranges and Klamath Mountains in Oregon. Four domains were differentiated based on mapped geology and topography - the northern (~45° - 46° N), central (-44° - 45° N), south-central (-43° - 44° N) and southern regions (-42° - 43° N). Bedrock control, on the range scale, is indicated through the association of higher topography with exposures of more resistant volcanic and metamorphic rocks. Lithologic changes coincide with knickpoints on river longitudinal profiles between the latitudes of 43° - 45° N, where rock uplift appears to be low. Rock type seems to be a strong control on topographic relief in these regions. However, in the southern region and less somewhat in the north, where rock uplift rates are highest, changes in lithology along river profiles do not display significant knickpoints. Uplift likely controls river profile form in the northern and southern regions. Basin hypsometric integrals and drainage density values are relatively constant in the study area except in the central region. Rivers in this region are almost exclusively alluvial - whereas most rivers in the Coast Ranges are bedrock or mixed bedrock-alluvial types. These low values in the central region, coupled with the presence of alluvial channels, suggests that the topography is expressing signals of low to no rock uplift in this region. The correspondence seen between low uplift rates and bedrock control and high uplift rates and a transparent bedrock signal suggests that an uplift rate threshold may exist. This has implications for modeling topographic evolution in tectonically-active mountain belts. |
| Genre | Thesis |
| Topic | Morphotectonics -- Oregon |
| Identifier | http://hdl.handle.net/1957/9006 |
