The project goal is straight forward, to determine if landslides influence the cosmogenic radionuclide (CRN) inventory of grain-sizes in a steep tropical basin. By characterizing the nuclide input of landslide debris the research will determine the importance of landslide sources and develop a mass and nuclide model for basin-wide erosion rates. Specifically, the nuclide inventory of five grain-sizes collected from 1) the landslide debris, 2) integrated depth profiles from the landslide scar and 3) upstream channel sediment will be evaluated. Channel bedrock samples will also be collected to test the nuclide input of local sources for large grains. These data will result in a greater understanding of the processes that contribute sediment to the Rio Chagres and will assist in developing a mass and nuclide balance model to better characterize the basin-wide erosion rates in similar settings.
Erosion rates are a major issue for many places. Knowledge of these can help in planning, agricultural applications, and the analysis of flood frequencies. It has been possible for several years to estimate erosion rates from the ditribution of radionuclides that are contained in sediments. However, the concentration of these may depend on source of sediment and the grain sizes, leading to erroneous estimates. This project will evaluate whether the erosion rates in an areas affected by landsliding processes are affected by the size of the material in the sediments. This will lead to better precision in calculating erosion rates in the future.
