Research paperTesting the applicability of optically stimulated luminescence dating to Ocean Drilling Program cores

Chronologies for marine sediments are usually constructed by tuning marine proxies for global ice volume (δ18O) to the well understood variations in the Earth's orbit, by the identification of event horizons and/or by radiocarbon dating. However, these techniques are not universally applicable. Optically stimulated luminescence dating (OSL) is potentially widely applicable to marine cores and may offer significant advantages over more conventional chronometric techniques but methodological considerations regarding the application of the techniques have yet to be systematically explored. Using material from core Ocean Drilling Program (ODP) core 658B, we assess the applicability of OSL dating to deep ocean sediments. For this core, equivalent dose does not change with depth below the split core face beyond the upper 1 mm, indicating that retrieval and prolonged storage of ODP material does not compromise the OSL signal. However equivalent dose decreases with increasing particle size, reaching a plateau at ∼30-40 μm. These data suggest that ocean floor sediment reworking causes the deposition of old material at the sediment-water interface, potentially resulting in OSL age overestimates. This observation strongly suggests that seafloor reworking processes should be considered both when selecting target cores and when interpreting results. Nonetheless, we observe a good general agreement between OSL ages and independent age estimates for a suite of sediments from the Marine Isotope Stage 6-5e transition, suggesting that the application of luminescence dating techniques to deep-sea sediments merits further investigation.