Wiggle-Match Dating of Tree-Ring Sequences

Abstract

Given the non-monotonic form of the radiocarbon calibration curve, the precision of single 14C dates on the calendar timescale will always be limited. One way around this limitation is through comparison of time-series, which should exhibit the same irregular patterning as the calibration curve. This approach can be employed most directly in the case of wood samples with many years growth present (but not able to be dated by dendrochronology), where the tree-ring series of unknown date can be compared against the similarly constructed 14C calibration curve built from known-age wood. This process of curve-fitting has come to be called “wiggle-matching.”In this paper, we look at the requirements for getting good precision by this method: sequence length, sampling frequency, and measurement precision. We also look at 3 case studies: one a piece of wood which has been independently dendrochronologically dated, and two others of unknown age relating to archaeological activity at Silchester, UK (Roman) and Miletos, Anatolia (relating to the volcanic eruption at Thera).

Tropical cloud forest climate variability and the demise of the Monteverde golden toad

“…The older (1900-1949) portion of the chronology has an estimated maximum age model error of AE2 yr due to slower growth rates and lower radiocarbon precision. The actual calendar dates that could be realistically associated with the radiocarbon assays, particularly on MV15, can be better constrained using Bayesian probability estimates between the radiocarbon calibration curve and the sample measurements (52)(53)(54). The likely dates are restricted foremost by the growth orientation of the tree-that is, samples from near the bark must be more recently formed than those near the center of treeand secondly using the number of annual cycles between each Δ 14 C measurement, in order to determine the most probable interval spanned by the core.…”

Towards High-Precision AMS: Progress and Limitations

“…However, the pretreatment methods applied to charcoal are a subset of those applied to wood, so the tree-ring data is pertinent here. In addition, some measurements do have internal checks as in the case of wigglematched dating of charred wood from Miletos (Galimberti et al 2004). In this instance, we have 7 decades of charcoal from a wiggle-matched piece of wood.…”

A Wiggle-Matched Date for the Copper Age Cemetery at Manerba Del Garda, Northern Italy

“…This chronology does not currently cross-date against any other available tree-ring chronology, and its relatively short length, and rather erratic pattern, likely preclude a successful dendrochronological crossmatch dating in isolation. Therefore, to obtain a relatively precise approximate absolute date for the sample, we employed 14 C wiggle-match dating of the tree-ring series Bayliss and Tyers 2004;Galimberti et al 2004). …”