LUMINESCENCE DATING: SHEDDING LIGHT ON COMPLEX SOIL AND ARCHAEOLOGICAL SITE FORMATION (Invited Presentation)

Luminescence dating is routinely applied to sediments and pottery to provide an age of last exposure of mineral grains to light or heat, which resets the luminescence clock. In contrast to older techniques, new methods use optically stimulated luminescence (OSL) dating and applications include single-grain dating of sand-sized grains. Refinement in OSL dating in the 21st Century has allowed the expansion of applications beyond well-bleached (zeroed) eolian and fluvial deposits and new applications include previously ‘untouchable’ deposits such colluvium, soils and anthropogenic deposits and features. In fact, while it has long been recognized that soils and anthropogenic living surfaces are not ideal for luminescence dating and should be avoided (e.g. Nelson et al. 2015), single-grain luminescence results and distribution of ‘ages’ from individual grains are particularly useful in shedding light on bioturbation and other site processes that can create a perplexing palimpsest of artifacts and age-reversals using traditional dating techniques. This presentation will provide examples of applications of OSL to settings with complex relationships between soils and archaeological horizons and advise on best practices for sample collection. New approaches and opportunities afforded by luminescence dating in archaeological settings will be discussed along with remaining challenges.