Luminescence, Soils

Establishing chronologies for profiles of soils and for young sedimentary deposits is an essential aspect of quantifying sediment transport processes and rates. Dating soils also enjoys wide application to archaeology, land-use management, tectonic geology, and sedimentary geology. It is, however, exceedingly difficult to do and decades of work involving scores of researchers and a wide variety of methodologies have been devoted to it. Luminescence dating, specifically OSL and especially single-grain OSL, shows great promise as the leading methodology that enables both an accurate and precise dating tool that is ideally suited to the task. There are, however, essentially only two studies that have applied single-grain OSL dating to the rich problem of dating soils and using the dates to better understand erosional processes. The other applications of dating soils (sediments) have focused on the age of the deposit for archaeological needs rather than geomorphic. There are many challenges to overcome before this methodology becomes more widespread. First and foremost is the fact that sample collection is challenging and needs to be carefully tailored to the process geomorphology of the site in question. Second and related to the first because of the limits on sample numbers is that the method is relatively expensive, with each analysis approaching the cost of obtaining a cosmogenic nuclide age analysis. Third, there remain sources of significant uncertainty in establishing the particle flow paths such that interpreting the OSL age can be a challenge. Given the nearly endless list of exciting scientific problems that can be tackled using luminescence dating of soils, it is likely that these challenges will soon be overcome and this method will truly shine.