|2005 Salt Lake City Annual Meeting (October 16–19, 2005)|
|Paper No. 83-13|
|Presentation Time: 11:25 AM-11:40 AM|
LONG-TERM EROSION RATES OF COASTAL WATERSHEDS IN THE PACIFIC NORTHWEST
GENDASZEK, Andrew1, THOMPSON, Nathaniel1, BALCO, Greg2, TODD, Claire1, and STONE, John2, (1) Earth and Space Sciences, University of Washington, 310 Condon Hall, Box 351310, Seattle, WA 98195, email@example.com, (2) Dept of Earth and Space Sciences and Quaternary Research Center, Univ of Washington, Seattle, WA 98195-1310|
We measured the Be-10 concentration of alluvial sediment leaving 16 coastal watersheds in Northern California and Oregon to determine mean basin-wide erosion rates of the Northwest Coast Ranges. The large spatial scale of these watersheds allows us to relate erosion rates to uplift rates between latitudes 39 degrees and 47 degrees north. Erosion rates are highest in Northern California, approaching 0.8 mm/yr in the Van Duzen River watershed, and reach a low of less than 0.1 mm/yr in the Central Oregon Coast Range, but increase again in the northern part of the Oregon Coast Range (see graph below). Our data confirm previous suggestions that erosion rates balance rock uplift in the Central Oregon Coast Range. To the south, near the Mendocino Triple Junction, our basin-scale erosion rate estimates of 0.3 - 0.8 mm/yr are lower than estimated uplift rates of 1 mm/yr. This suggests that rock uplift may be outpacing erosion, leading to an increase in the average elevation of the coast range, but the comparison is complicated by differences in the spatial scale and averaging time of the uplift and erosion rate measurements.
2005 Salt Lake City Annual Meeting (October 16–19, 2005)
General Information for this Meeting
|Session No. 83|
Thermochronology: Techniques, Applications, and Interpretations I
Salt Palace Convention Center: Ballroom B
8:00 AM-12:00 PM, Monday, 17 October 2005
Geological Society of America Abstracts with Programs, Vol. 37, No. 7, p. 200
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