Chemistry Reference
In-Depth Information
From the amount or radiocarbon in archaeological remains, it is rela-
tively easy to calculate the time of death of a living organism, that is, to
determine the time elapsed since its dead remains became separated from
the carbon exchange reservoir. It is important, particularly in archaeology,
to remember that radiocarbon dates provide only the time of death of
organisms. Materials such as wood, for example, which were used in the
past for building or for making tools, might have been derived from trees
that had been dead for a long time before their wood was used. It should
also be noted that the time of removal of a tree from the radiocarbon
exchange reservoir, that is, the time of death of its wood, may be valid
only for the outer part of the trunk or branches. Often, the inner part of
the trunk and branches of a tree are dead, while the outer layers are still
growing. The time of death of the inner core may be much earlier than
that of the outer wood - often even before the latter was only being
formed. In any case, the radiocarbon method provides only the maximum
possible age of a material, revealing solely when living matter died, not
when it was put to use (Hedges 2000).
The list below provides a rather limited but nevertheless impressive
inventory of materials that have been dated with the technique:
Antler
Avian eggshells
Blood
Bone
Cement
Charcoal
Coprolites
Coral
DNA
Fats
Feathers
Ferrous alloys
Fibers
Glue
Gum
Hair
Hide
Horn
Incense
Ivory
Leather
Mortar
Oils
Paints
Paper
Papyrus
Parchment
Peat
Plaster
Pollen
Pottery
Resins
RNA
Seeds
Shell
Skin
Slags
Soil
Teeth
Textile fabrics
Varnish
Vellum
Waxes
Wood
Methodology of Radiocarbon Dating.
The natural concentration of
radiocarbon in materials on earth is extremely low; add to this the fact that
the beta radiation emitted by radiocarbon is very weak, and the conclusion
is that the measurement of natural levels of radiocarbon is a rather difficult
task. Indeed, very elaborate physical and chemical procedures are required
to obtain accurate radiocarbon measurements and dates.
