Quartz luminescence as a light-sensitive indicator of sediment transport in coastal processes

Samples of sand collected from a beach profile after a storm were studied u sing thermoluminescence (TL) and optically stimulated luminescence (OSL). B oth methods yield signals from quartz which are depleted as a function of t he duration of previous light exposure, but with different fractional loss constants for TL vs. OSL. A strong gradient in the TL signal intensity as a function of position on the beach profile was found. This apparently arise s because of differences in the duration of natural light exposure experien ced during the six hour period after the sand was moved from the nearshore underwater environment onto the beach. Laboratory experiments established t hat TL signals can distinguish between exposure time differences ranging fr om about 30 minutes to about 6 hours for the quartz from the locality studi ed. OSL signals were absent in both offshore and onshore samples, as would be expected because OSL signals can be completely depleted within seconds t o minutes for most quartz sediments. Use of TL differences with quartz expo sure times is proposed as a tool for study of various coastal depositional processes, with obvious implications for engineering of coastal structures and sand mining. It is hoped that professionals in these areas and sediment ologists might consider how this tool, which should be very simple to apply , might be applicable to their own particular areas of interest.