Swale and Ure Washlands :Single-grain optically stimulated luminescence measurements of fluvial and fluvioglacial sediments
Author(s): H M Roberts, Geoff A T Duller
Eight samples of fluvioglacial origin and one from a Holocene fluvial deposit were collected from the area around Ripon, with the aim of providing chronological constraints on the deglaciation of the area at the end of the Devensian. The depositional environments are such that there was a concern that not all the mineral grains in the sediment may have been exposed to daylight at deposition. Therefore, luminescence measurements were made on single sand-sized grains of quartz. The signals from these were generally very dim, with only very few grains (0.9%–2.2%) giving detectable optically stimulated luminescence (OSL). In spite of rigorous sample preparation to extract pure quartz, investigations demonstrated that many of these OSL signals originated from non-quartz minerals, probably feldspar inclusions. After rejecting grains with these signals, only 0.1–0.6% of grains remained for the eight fluvioglacial samples, and this was insufficient to allow an age to be determined. For the one fluvial sample a slightly higher proportion (1.0%) of grains was accepted. Statistical analysis was problematic because of the low recovery of suitable grains, but the results broadly agreed with independent age control.
- Report Number:
- 31/2007
- Series:
- Research Department Reports
- Pages:
- 16
- Keywords:
- Geochronology Optically Stimulated Luminescence
