Since the mid-1990s, we have been measuring 10-Be in river and stream sediment to learn more about the rate at which drainage basins erode and rivers mix sediment. This work has included study of some of the world's great mountain systems as well as work in lowlands and ancient mountain belts. From the isotopic data, we interpret erosion rates and use these to test geomorphic models and to compare long-term rates of erosion with short-term rates of sediment yield.

A finding common to all river systems in which we have worked is the decrease in variability of nuclide concentration with basin area. Clearly, fluvial systems mix sediment effectively even in arid regions where flow is intermittent.

This research has been supported by the DoD, NSF, and the USGS.

Relevant Publications:

• Safran. E., Bierman, P.R., Aalto, R., Dunne, T., Whipple, K., and Caffee, M. (2005). Erosion rates driven by channel network incision in the Bolivian Andes. Earth Surface Processes and Landforms. 30(8): 1007
   
• Bierman, P. R. and Nichols, K.K. (2004) Rock to sediment - Slope to sea with 10Be - Rates of landscape change, Annual Review of Earth Science. v. 32. p. 215-255
   
• Bierman, P. and Steig, E. (1996) Estimating rates of denudation and sediment transport using cosmogenic isotope abundances in sediment. Earth Surface Processes and Landforms, 21, 125-139.
   
• Bierman, P., Clapp, E.M., Nichols, K.K, Gillespie, A.R., Caffee, M. (2001) Using cosmogenic nuclide measurements in sediments to understand background rates of erosion and sediment transport, in Landscape Erosion and Evolution Modeling, Harmon, R. S. and Doe, W. W., eds., Kluwer/Plenum, New York. p. 89-116.