Luminescence dating applications in geomorphological research

Chronological control remains critical to the interpretation of environmental change and to establishing long-term rates of geomorphological processes. Radiocarbon dating will continue to be the central technique for age assessment of carbon-bearing sediments deposited in the last ca. 40 ka, but alternative absolute dating strategies are required for older or non-carbon-bearing sediments. They include uranium-series dating of precipitated sediments, K–Ar and Ar–Ar dating of primary volcanic materials, and cosmogenic isotopic dating of surface exposure ages. An additional family of methods, collectively termed luminescence techniques, is increasingly providing a basis for the age assessment of detrital sedimentary deposits. These methods directly date the deposition of detrital mineral grains (typically quartz and feldspar) and have been demonstrated to provide accurate deposition chronologies for up to 800 ka, although 150 ka is more typical. In the past decade, a subset of luminescence techniques which employ optical sample stimulation methods (called optical dating) has made it possible to date samples from a much wider range of depositional systems. Given that the methods directly date sedimentation, they allow direct assessment of depositional dynamism in numerous terrestrial and subaqueous (including marine) sedimentary systems, and have demonstrated particular potential in the elucidation of chronologies from aeolian (dune and loess), fluvial, colluvial, coastal, and volcaniclastic environments. This paper provides a summary of the principles of the luminescence (especially optical) dating methods and shows how recent developments (specifically single aliquot dating procedures) have dramatically enhanced the scope and potential of the method. The luminescence techniques are increasingly being incorporated into a wide range of geomorphological studies which seek to establish the nature of landscape changes over the past interglacial–glacial cycle and beyond.