The full programme book (PDF) - Royal Geographical Society

THEME 2: MEASURING TIME
Radiocarbon dating and its revolutions
Christopher Bronk Ramsey
Research Laboratory for Archaeology and the History of Art, University of Oxford, Dyson Perrins
Building, South Parks Road, Oxford
The term “Radiocarbon Revolution” was first used to describe the impact on archaeology
of Willard Libby's 1949 discovery of the dating technique over the succeeding two
decades. The term is equally valid in describing the impact on environmental sciences.
Soon after the discovery, however, it was realised that radiocarbon dates required
calibration. The development of tree-ring based calibration is often referred to as the
second radiocarbon revolution. The calibration revolution has continued ever since, as the
period covered has edged steadily back to the limit of the technique. It is no coincidence
that the duration of this particular revolution has coincided with the existence of the QRA,
many of whose members have contributed significantly to the enterprise.
In the wake of the first two revolutions it is easy to lose count of subsequent developments
that have been termed ‘revolutionary’. The development of Accelerator Mass
Spectrometry (AMS), allowing the measurement of smaller samples and therefore
samples of different types, was responsible for an explosion in the number of
measurements available, and this has had a profound impact on the application of the
technique. Another revolution has been seen in our understanding of the dating of the
Palaeolithic, through new chemical methods that allow accurate dating of materials like
bone and charcoal towards the limit of the technique. With the explosion of data have
come equally important developments in statistics and information technology, made
possible by the widespread availability of powerful computers. Just as Geographic
Information Systems (GIS) have revolutionised the way we use spatial information, so
chronological modelling approaches have revolutionised the way in which we use dating
information. This is a revolution that is still in its infancy. As we aim to combine information
from many different dating techniques in ways that allow us to better understand
processes of change throughout the Quaternary it is clear that the boundaries between
understanding chronology and understanding environmental processes have broken
down: chronology is no longer something which is imported into Quaternary research, it
must be fully integrated with it.
Keywords: radiocarbon; quaternary geochronology; Bayesian age modelling; quaternary
environments; archaeology; accelerator mass spectrometry.