Document Type
Article
Department/Program
Virginia Institute of Marine Science
Publication Date
9-2006
Journal
Global Biogeochemical Cycles
Volume
20
Issue
3
First Page
GB3022
Abstract
To assess the role that erosion processes play in governing the character of particulate organic carbon (POC) discharged from small mountainous and upland rivers, a suite of watersheds from Oregon, California, and New Zealand was investigated. The rivers share similar geology, tectonic setting, and climate, but have sediment yields that range over 3 orders of magnitude. The (14)C age of the POC loads is highly correlated with sediment yield. Carbon isotope mass balances reveal that the rivers carry bimodal mixtures of modern-plant-and ancient-rock-derived OC. At lower yields, modern plant OC dominates the material delivered to the river by sheetwash and shallow landsliding. With increasing yield, a progressively larger part of the POC is contributed directly from bedrock erosion via deep gully incision. Our results support the inference that active margin watersheds are important sources of aged POC to the ocean.
DOI
10.1029/2005GB002677
Keywords
Oregon Coast Range; Digital Elevation Models; New-Zealand; Gully Erosion; Sediment Discharge
Recommended Citation
Leithold, EL; Blair, NE; and Perkey, DW, Geomorphologic controls on the age of particulate organic carbon from small mountainous and upland rivers (2006). Global Biogeochemical Cycles, 20(3), GB3022.
10.1029/2005GB002677
