ESTIMATING RATES OF DENUDATION USING COSMOGENIC ISOTOPE ABUNDANCES IN SEDIMENT

• Published in: Earth surface processes and landforms Vol. 21; no. 2; pp. 125 - 139
• Main Authors: BIERMAN, PAUL, STEIG, ERIC J.
• Format: Journal Article
• Language: English
• Published: Sussex John Wiley & Sons, Ltd 01.02.1996; Wiley
• Subjects: Bgi / Prodig; cosmogenic isotopes; denudation rate; erosion; Geomorphology; hillslope; Methods and techniques; modelling; Physical geography; sediment budget; Erosion rate; Soil erosion; Methodology; Watershed; Model; Isotope analysis; Sediment budget
• ISSN: 0197-9337; 1096-9837
• DOI: 10.1002/(SICI)1096-9837(199602)21:2<125::AID-ESP511>3.0.CO;2-8

We propose, as a testable hypothesis, a basin‐scale approach for interpreting the abundance of in situ produced cosmogenic isotopes, an approach which considers explicitly both the isotope and sediment flux through a drainage basin. Unlike most existing models, which are appropriate for evaluating in situproduced cosmogenic isotope abundance at discrete points on Earth's surface, our model is designed for interpreting isotope abundance in sediment. Because sediment is a mixture of materials, in favourable cases derived from throughout a drainage basin, we suggest that measured isotope abundances may reflect spatially averaged rates of erosion. We investigate the assumptions and behaviour of our model and conclude that it could provide geomorphologists with a relatively simple means by which to constrain the rate of landscape evolution if a basin is in isotopic steady state and if sampled sediments are well mixed.