Evaluating Luminescence as a Means to Understand Controls on Sediment Transport

Determining the controls on fluvial sediment transport remains an important goal for understanding how landscape signals propagate into the sedimentary record. However, sediment transport information, such as the virtual velocity and channel-floodplain exchange rates, is often difficult to quantify. This information is important for interpreting the sedimentary record because the time spent in transport and/or in storage can significantly modify landscape signals. Luminescence, with its dynamic nature of trapped-charge growth during sediment storage and charge release (bleaching) during transport, offers a unique potential means to obtain information on the mechanisms of sediment transport. This approach may allow us to measure sediment transport information over longer timescales than is currently possible with modern field methods. Recently, a model coupling the physics of luminescence with sediment transport was able to accurately reproduce the spatial patterns of luminescence observed in previously published datasets. The model also apparently produced realistic sediment transport values suggesting that the method has significant potential as a sediment transport indicator. However no independent verification of these values was possible. As a test of this finding, we explore the use of a coupled luminescence and suspended-sediment transport model in reproducing the sediment transport information observed by independent methods for three rivers in the Mid-Atlantic region of the United States. We explore where the model is successful or unsuccessful and how this relates to underlying model assumptions concerning sediment transport, sediment storage, and luminescence change. We conclude that luminescence may have significant potential as a means to quantify sediment transport due to its ease of use on ubiquitous quartz and feldspar sand.