Evaluating optically stimulated luminescence rock surface exposure dating as a novel approach for reconstructing coastal boulder movement on decadal to centennial timescales

Abstract. Wave-transported boulders represent important records of storm and tsunami impact over geological timescales. Their use for hazard assessment requires chronological information on their displacement that in many cases cannot be achieved by established dating approaches. To fill this gap, study investigated, the first time, potential optically stimulated luminescence rock surface exposure (OSL-RSED) estimating cliff-detachment ages wave-transported coastal boulders. The approach was tested calcarenite clasts at Rabat coast, Morocco. Calibration OSL-RSED model based samples with surfaces exposed to sunlight ∼ 2 years, OSL were evaluated against age control deduced from satellite images. Our results show precision is limited all targeted due local source lithology which has low amounts quartz feldspar. accuracy may affected erosion rates boulder 0.02–0.18 mm yr−1. Nevertheless, we propose a robust relative chronology are not significant post-depositional share angles inclination calibration samples. indicates (i) most detached cliff waves; (ii) these storms lifted masses up 24 t; (iii) role formation deposits along coast more than previously assumed. Although provide reliable absolute study, large composed rocks larger or feldspar less susceptibility erosion.