Low optically stimulated luminescence (OSL) sensitivity is commonly observed in quartz from tectonically active catchments, suggesting limited or short-lived conditions favorable for sensitization. We characterize the OSL sensitivity of quartz sand within a small, tectonically active catchment in Sicily using modern fluvial samples and a hillslope soil sample. We investigate how OSL sensitivity varies with bedrock lithology, weathering proxies, and topographic metrics. OSL sensitivity spans three orders of magnitude (60–2800 counts/Gy/mm3) with no clear linkage to bedrock source. The soil sample exhibits the highest OSL sensitivity, and positive relationships between OSL sensitivity, magnetic susceptibility, and weathering intensity suggest that pedogenic hillslope processes enhance quartz OSL sensitivity. In contrast, fluvial sediments show low OSL sensitivity and a modest inverse relationship to channel steepness and hypsometry. OSL sensitivity decreases downstream, suggesting that highly sensitized grains from hillslope soils are progressively diluted by low OSL sensitivity sediment likely generated by rapid bedrock erosion in the catchment. These results highlight a hierarchy of controls: bedrock lithology sets the initial OSL sensitivity, hillslope processes enhance it, rapid erosion dilutes it, and fluvial transport modulates it through mixing, explaining why tectonically active catchments rarely preserve quartz with high OSL sensitivity.

The optically stimulated luminescence (OSL) sensitivity of quartz ranges across five orders of magnitude. Previous studies suggested that quartz OSL sensitivity is enhanced by solar exposure–burial irradiation cycles. Spatially resolved luminescence measurements and laboratory illumination–irradiation experiments were used to investigate the OSL sensitivity of quartz crystals from a granodiorite cobble and quartz grains from a fluvial sand. Quartz from the granodiorite cobble has low OSL sensitivity, showing an approximately linear sensitization path that resulted from laboratory illumination–irradiation cycles. The mean OSL sensitivity of quartz sand grains (100 grains) increased from ∼40 to 80 counts after 1260 illumination–irradiation cycles. Each grain has a specific sensitization trajectory due to illumination–irradiation cycles, suggesting that quartz crystal composition heterogeneities drive the OSL sensitization of their daughter sediment grains. Maximum OSL sensitivity of quartz sand grains is reached after illumination–irradiation cycles representing an accumulated dose of around 4000 Gy. This dose corresponds to sediment burial time of 2–4 Ma, which is unlikely to occur during a single sediment transport route. This study suggests that illumination–irradiation cycles are unable to produce quartz sand grains with OSL sensitivity up to five orders of magnitude higher than the sensitivity of parent crystals in igneous or metamorphic rocks.

Although luminescence sensitivity of quartz grains of desert sands has been used in discriminating provenance, it still remains unclear about its spatiotemporal variations and climatic implications. In this paper, the luminescence sensitivity of quartz grains from the northern margin of the Chinese Loess Plateau (CLP) was studied using single-aliquot optically stimulated luminescence (OSL) and “pseudo” single-grain OSL measurements. Our results indicate that the OSL sensitivities have lower values in sand/loess beds and higher values in paleosols. We suggest that the variations in OSL sensitivity of quartz grains with depth on the CLP are mainly influenced by the origin of the quartz grains as they are related to the loess-sized material production processes and the migration of desert regions. More quartz grains of glacial origin with lower luminescence sensitivity, together with the reduced durations of irradiation and exposure cycles induced by shorter transport distance due to desert expansion, account for the lower luminescence sensitivity of glacial periods. Moreover, both the mountain processes and the retreat–advance of deserts are ultimately related to climatic changes, therefore, the orbital scale variations of luminescence sensitivity are controlled by glacial–interglacial oscillations on the CLP.