Refining the Hallstatt Plateau: Short-Term¹⁴C Variability and Small Scale Offsets in 50 Consecutive Single Tree-Rings from Southwest Scotland Dendro-Dated to 510–460 BC

Abstract

ABSTRACT. Radiocarbon ( 14 C) wiggle-match dating is a technique with a substantial potential to improve the precision of dating timbers in situations where dendrochronology is not tenable. However, one of the key reasons why obtaining a dendrochronological determination might be difficult is the short-lived nature of timbers on a range of archaeological sites, something that also affects the efficiency of the wiggle-match dating technique. Combined with the potential for high expense that the technique presents, it is paramount that wiggle-match dating research design has a good empirical basis. To this end we dated 50 consecutive, individual rings from a timber that grew during the Hallstatt radiocarbon calibration plateau (ca. 750-400 cal BC) in southwest Scotland. The results indicate that (1) the precision and accuracy of wiggle-match dates carried out on short-lived sequences during the Hallstatt plateau may suffer due to insufficient resolution of the calibration data, (2) sampling time-frames roughly equivalent to the underpinning calibration data are recommended (for the period in question this means decadal blocks), and (3) short-lived sequences are at risk of losing accuracy if the actual past trend of radiocarbon diverges from the mean of the radiocarbon calibration curve.

More Rapid 14C Excursions in the Tree-Ring Record: A Record of Different Kind of Solar Activity at About 800 BC?

“…We note that the decline of 30‰ in 14 C effectively cancels the increase in 14 C over 200 years with a decrease in 14 C age equivalent to 240 years in the younger (550 BC) sample. This effect causes a relatively flat period in apparent 14 C age, as has been noted by earlier studies and referred to as the Hallstatt period (Friedrich and Henning 1996;Grabner et al 2007;Jacobssen et al 2017). To continue our comparison with the 660 BC event (Park et al 2017), we note the rise time of that event is about 11-12 years between BC 667.5 to 659.5, similar to the increase observed in 814-804 BC and the 5480 BC event (Miyake et al 2017a).…”

“…Moreover, measuring 14 C on tree rings around the cosmogenic event(s) provides the opportunity to date an archaeological occurrence to a single year (Wacker et al 2014). We note also the importance of the Hallstatt period in 14 C dating (Friedrich and Henning 1997;van der Plicht 2004;Grabner et al 2007;Jacobssen et al 2017), due to its original association with LBA mine workings at Hallstatt in Austria. Therefore, if we can improve our understanding of the detailed structure of the 14 C record in this period, this also has implications for archaeological dating in this region, as well as for our understanding of solar effects on climate.…”

Chronology of the Archaeological Site of Playa Del Mango, Rio Cauto, Granma, Cuba

“…The 14 C age for the shark vertebra (ornament) associated with PM1_e-T4 (the sample that failed to produce results) overlaps the Hallstatt Plateau in the calibration curve (Jacobsson et al 2017). The resulting wide age range [from cal BC 110-AD 394 (2 σ)] overlaps the 14 C age for the PM1_M44, supporting that it was a PM1_e-T4 burial inclusion.…”

High‐resolution proglacial lake records of pre‐Little Ice Age glacier advance, northeast Greenland

“…a BP (sample ZAC-2, 11.0-12.0 cm depth). The overlapping calibrated age range of ZAC-1 and ZAC-2 is a product of the 14 C calibration curve plateau (Hallstatt plateau) and is not thought to reflect a true age inversion of the sample (Jacobsson et al 2018). Above these dated horizons, the upper-most laminations remain horizontally bedded, but it cannot be ruled out that this part of the succession (i.e.…”