Direct dating in archaeology
The extent of documentation varied considerably in 'historical' cultures and the information that survives is determined by a variety of factors.
If a context containing burnt debris and broken artefacts is excavated on a site from a historical period, it is tempting to search the local historical framework for references to warfare or a disaster in the region, and to date the excavated context accordingly.
Petrie used sequence dating to work back from the earliest historical phases of Egypt into pre-dynastic Neolithic times, using groups of contemporary artefacts deposited together at a single time in graves.Different researchers have applied a variety of absolute dating methods directly to petroglyphs or to sediments covering them, including AMS (accelerator mass spectrometry) radiocarbon, cation ratio, amino acid racemization, OSL (optically stimulated luminescence), lichenometry, micro-erosion and micro-stratification analysis of patina. These techniques have yielded mixed results in terms of reliability and feasibility, but, in any case, none has been applied to date in Saudi Arabia.It is hoped that absolute dating will be successfully implemented in the future in this region.The age is obtained by calculating the dose received compared to the dose rate generated by the surrounding environment, mainly radioisotopes K, U, and Th.The dating range is dependent on the nature and state of conservation of the sample and the surrounding environment but is between a few thousands and a couple of million years.