Radiocarbon Dating to a Single Year by Means of Rapid Atmospheric ¹⁴C Changes

Abstract

In the best case, radiocarbon measurements allow artificial objects to be dated with a precision of 10 calendar years when conventional wiggle-matching onto the IntCal09 calibration curve is applied. More precise dating can only be achieved by using annually resolved 14 C calibration data, particularly in timespans when there are rapid changes in atmospheric 14 C concentration. The recently observed jump in atmospheric 14 C concentration of 1.5% between AD 774 and 775, though expected to be rare, is a good example for such a rapid change. We demonstrate by example that is possible to precisely 14 C date the cutting year of a timber in the historically important and well-preserved Holy Cross chapel of the convent St. John the Baptist in Val Müstair, Switzerland.

Increase of radiocarbon concentration in tree rings from Kujawy (SE Poland) around AD 774–775

“…A short-lived 14 C sample formed in AD 775, such as a leaf or seed, could appear to date to the early tenth century if its 14 C age is calibrated using the international consensus calibration curve for the Northern Hemisphere [11]. On the other hand, the 14 C peak means that wood samples spanning the AD 770s can be wiggle-matched precisely: for example, Wacker et al [12] used a series of 7 14 C samples from single annual rings in a conifer timber from Holy Cross chapel, St John's convent (Müstair, Switzerland) to confirm a tentative dendrochronological felling date of winter AD 785/6 for this timber.…”

RICH – A new AMS facility at the Royal Institute for Cultural Heritage, Brussels, Belgium

“…The good performance is demonstrated by the good accuracy and precision on known standards and low backgrounds are measured. A future aim is the performance of high-precision radiocarbon measurements (<0.2%) as described in [15].…”

Status of mass spectrometric radiocarbon detection at ETHZ

“…Hence the results are accurate, and the scatter between results for different aliquots of the same sample appears to be correctable by averaging between multiple aliquots. The precision is sufficient for many dating applications, though today precisions of less than 0.2% are reached on larger systems [14]. The normalized blank level corresponds to a radiocarbon age of about 40,000 years, similar to what was seen in the proof-of-principle experiment.…”

“…The feasibility of mass spectrometric 14 C detection has been shown in a proof-of-principle experiment called lCADAS [1]. This was a temporary setup and was built out of components from two MICADAS systems which are now in use in Debrecen [2] and at the Centro Nacional de Aceleradores (CNA) in Seville, Spain.…”