Optically stimulated luminescence dating
However, such uncertainties do not apply to grains measured individually. Age models constitute a statistical means of recognizing clusters of grains with distinct exposure/burial histories within a sample (Galbraith et al.
masonry, slabs, orthostats, and pillars) would receive sufficient daylight before they were assembled together to erect the structure.Examples of OSL dating illustrate its use in palaeoenvironmental and archaeological contexts, although problems associated with the technique are also addressed.Finally, we discuss long-range variants of OSL that may help date deposits currently considered too old for OSL to be applied.This article reviews optically stimulated luminescence (OSL) dating as used on Quaternary sediments and for archaeological dating.The underlying physics is summarized and the laboratory method itself is described.For this purpose, in addition to archaeological and geomorphological reasoning, radiocarbon dating (C) is used to date organic materials.
But in view of its ineffectiveness to date materials older than 50 ka and the omnipresence of (inorganic) clastic sediments in most depositional contexts, optically stimulated luminescence (OSL) dating and its long-range dating alternatives are indispensable.
In the case of feldspar, released luminescence is termed infrared stimulated luminescence (IRSL).
However, feldspars frequently undergo loss of trapped electrons at ambient temperatures, a phenomenon known as anomalous fading (Wintle 1973), which, if not corrected, can result in severe age underestimation.
The last few decades have seen a significant impact of geoscience techniques and concepts on palaeoenvironmental and (geo)archaeological studies.
Geoarchaeology and palaeoenvironmental studies both require a solid chronological framework by which to recognize causes and effects, as well as rates of processes.
If an adequate amount of quartz grains can be extracted, which would involve only sampling the surface of the stone, then conventional OSL dating protocols could be employed to generate a numerical age for the structure. The degree of tolerance to precision is case-specific but, usually, anything less than 10% is satisfactory. These include intrinsic ones related to the crystalline properties of the material, or extrinsic ones due to factors such as differential bleaching or post-depositional sediment mixing.