The way that we do this is through sampling sand from the landforms in opaque plastic tubes and taking the sample back to a luminescence laboratory where only red light conditions are used. Optically stimulated luminescence dating of glaciofluvial sediments on the Canterbury Plains, South Island, New Zealand. We have to be very careful not to expose the sediments to sunlight when we do this! The equivalent dose value is measured in the SI unit “grays” (Gy). Depositional pathway tracing in glacial catchments using the OSL of coarse-grained quartz and K-feldspar. Measuring the environmental dose rate for an OSL sample from Glen Tulla, Scotland. This can be measured either at the sample location using a portable gamma spectrometer, through measurement of alpha, beta and gamma counts in the laboratory, or through direct measurement of uranium, thorium and potassium concentrations using inductively-coupled plasma mass spectrometry. The methods through which dose rates are calculated vary between different laboratories worldwide.
| Calculating Age | Challenges for OSL | Case studies of OSL dating in glacial environments | References | Comments | Another way of dating glacial landforms is optically stimulated luminescence dating (OSL). When these quartz or feldspar minerals are exposed to the ionising radiation emitted by the radioactive isotopes in zircons, electrons within the crystals migrate and become trapped in their crystal structure. The number of trapped electrons depends on the total amount of radiation that the mineral has been exposed to. We measure this emitted light (the luminescence) and this is the first stage towards measuring the sample age. We then give our sand sample a range of laboratory radiation doses and measure the luminescence that each dose produces to develop a calibration curve. From this curve we can calculate the dose that our sample must have received to produce the amount of light that we measured first.