TESTING THE RELATIONSHIP BETWEEN MINERAL SUPPLY RATES AND CHEMICAL EROSION IN THE KLAMATH MOUNTAINS (Invited Presentation)

The relationship between rates of chemical erosion and mineral supply is central to many problems in Earth science, including how tightly Earth’s climate should be coupled to tectonics, how strongly nutrient supply to soils and streams depends on soil production, and how much lithology affects landscape evolution. We aim to test this relationship in the forested uplands of the Klamath mountains, along a latitudinal transect of granodioritic plutons that spans an expected gradient in mineral supply rates associated with the geodynamic response to the migration of the Mendocino Triple Junction. Here, we present new ¹⁰Be-derived erosion rates and Zr-derived chemical depletion factors, as well as bulk soil and rock geochemistry on 10 ridgetops along the transect to test hypotheses about supply-limited and kinetically-limited chemical erosion. Previous studies in this area suggest a balance between rock uplift rates and basin wide erosion rates, implying the study ridgetops may have adjusted to an approximate steady state. Preliminary results suggest that chemical erosion rates at these sites are influenced by both mineral supply rates and dissolution kinetics.