Uncertainty with carbon 14 dating


By the late 1970s, the use of accelerator mass spectromettry (AMS) began gaining favor as a method for precisely counting carbon isotopes, following the production of catalytically condensed graphitic carbon (CCGC) from COC to the atmosphere, which is called the Libby Effect.

It is now possible to obtain an accurate and precise radiocarbon date from the Libby Effect era, due to reduced (but still elevated) concentrations in atmospheric C in the atmosphere and troposphere, the life cycle, and postmortem diagenesis of certain organisms as they relate to uptake of carbon molecules, the way to evaluate legacy (archival) radiocarbon ages and the significance of calibration as it relates to specific events in African prehistory.

This review will begin generally to explain the process of radiocarbon production in the atmosphere, and how three isotopes of carbon become associated with all living organisms that eventually die and find their way into the archaeologist’s sample collection.

Six issues will then be brought into focus facing archaeologists working in Africa that may not be common knowledge: (1) dating ostrich ( sp.) can provide overestimates of ages on the order of hundreds of years; (3) diagenetic changes in bone chemistry within archaeological contexts in hot and/or humid climates of Africa confound accurate C age estimations in many contexts; (4) nonclimate controlled archival storage of archaeological collections can promote the growth of microorganisms on artifacts, which can contribute to the datable carbon fraction; (5) legacy data may have been subject to systematic errors in processing and analyzing samples; and (6) wiggles and flatlines in the atmospheric concentrations of It is safe to assume that all professional archaeologists are generally aware of the radiocarbon dating technique, that it can be performed on carbon recovered in archaeological deposits, and handling datable materials is best done with relative care to avoid contaminating the materials with finger oils, cigarette ashes, or other environmental contaminants found on archaeological sites.

Legacy radiocarbon ages must be critically examined for what method was used to generate the age, and calibration radiocarbon ages from critical periods of African prehistory lack precision to resolve significant debates.

A multipronged dating strategy and careful selection of radiocarbon sample materials are advocated from the earliest stages of research design. Cette revue fournit les archéologues africanistes avec des appréciations et des mises en garde sur l’utilisation des âges radiocarbone.

External effects such as p H, temperature, and the microbial environment can amplify diagenesis while internal factors such as the crystal size, porosity, and solubility of the material also play a role (Zazzo and Saliège C ratio presumed in radiocarbon dating.