Radiocarbon allows us to date back to ~55,000 years ago. Beyond this, other techniques are required.
Optically Stimulated Luminescence (OSL) can routinely measure the age of sediments from 0–200,000 years and is therefore extremely useful in cases where the limit of the radiocarbon method is reached. In addition, for sites with no, or few, suitable organic samples for radiocarbon dating, analysis of mineral grains and burnt flint using OSL and TL (thermoluminescence), respectively, can provide the best means of securing a chronological framework for the sedimentological history and occupation of a Pleistocene site.
OSL dating provides an estimate of the time since grains of quartz or feldspar were last exposed to sunlight.
More advanced single-grain OSL analyses can help resolve issues affecting partially bleached sediments and inform us regarding site formation processes. This may help to assess the degree of mixing undergone in sediment processes and aid in identifying AMS specimens that are unlikely to be derived from secure contexts.
The PalaeoChron project will apply both optical and thermal luminescence dating methods to sites across Eurasia. This part of the project is led by Dr. Jean-Luc Schwenninger and Dr. Marine Frouin.
We have purchased a new LEXSYG Luminescence reader from Freiberg Instruments specifically for the research project. The new reader is optimised to allow continuous measurement using a 80-sample carousel.
The new luminescence reader has been purchased as part of the PalaeoChron ERC project.
Tom Higham and Jean Luc Schwenninger next to new LEXSYS luminescence reader, now called "CHRONOS"
OSL and TL dates can be incorporated in Bayesian statistical models and may also provide an independent check on radiocarbon dates, strengthening the reliability of the chronology at selected sites. It is crucial that at the timescale PalaeoChron is working multiple dating methods are adopted.