The age is obtained by measuring the radiation dose received by the sample since it was last bleached by sunlight and dividing this estimate by the dose rate from environmental sources of ionising radiation.
OSL dating can be used to determine the time since naturally occurring minerals, such as quartz and feldspar, were last exposed to light within the last few hundreds of thousands of years.
It is one of the main methods used to establish the timing of key events in archaeology and human evolution, landscape and climate change, and palaeobiology in the latter half of the Quaternary.
The laboratory has two portable gamma-ray spectrometry units to measure the on-site dose rate from gamma radiation, and laboratory determinations of sample radioactivity can be made using a Risø GM-25-5 low-level beta-counting unit and three Daybreak 583 thick-source alpha counters.
Amino acid racemisation dating of fossils, such as eggshell and mollusc shell, found at archaeological and geological sites is performed at the University of Wollongong in a new AAR laboratory housed in the School of Earth & Environmental Sciences.