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ABSTRACT Considered in isolation, the radiocarbon ( 14 C) dates on short-lived plant remains from the Jean-Baptiste Lainé (formerly Mantle) site, Ontario, yield an ambiguous result: more or less similar probability around AD 1500 or alternatively around AD 1600. This village site, likely of no more than ca. 20–30 years total duration, illustrates the challenges of high-resolution dating across periods with a reversal/plateau in the 14 C calibration curve. Another problem we identify is the tendency for dating probability for short-duration sites to sometimes be overly compressed as dating intensity increases under analysis with OxCal, and for probability to shift away from the real age range especially during reversal/plateau episodes. To address both issues additional constraints are necessary. While a tree-ring sequenced 14 C “wiggle-match” is the best option where available, we investigate how, in the absence of such an option, use of the in-built age in wood-charcoal samples can be used to distinguish the likely correct date range. This approach can resolve ambiguities in dating, e.g., for shorter-duration Late Woodland village sites in northeastern North America, but also other short-duration cases corresponding with reversal/plateau episodes on the 14 C calibration curve. We place the Jean-Baptiste Lainé site most likely more » in a range between ca. AD 1595–1626 (95.4% probability). « less
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National Science Foundation
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  1. ABSTRACT Reversals and plateaus in the radiocarbon ( 14 C) calibration curve lead to similar 14 C ages applying to a wide range of calendar dates, creating imprecision, ambiguity, and challenges for archaeological dating. Even with Bayesian chronological modeling, such periods remain a problem when no known order—e.g., a stratigraphic sequence—exists, and especially if site durations are relatively short. Using the reversal/plateau AD 1480–1630 and the archaeology of northeastern North America as our example, we consider possible strategies to improve chronological resolution across such reversal/plateau periods in the absence of stratigraphic sequences, including uses of wood-charcoal TPQs from even very short wiggle-matches, and site phase duration constraints based on ethnohistoric and archaeological evidence.
  2. Reversals and plateaus in the radiocarbon (14C) calibration curve lead to similar 14C ages applying to a wide range of calendar dates, creating imprecision, ambiguity, and challenges for archaeological dating. Even with Bayesian chronological modeling, such periods remain a problem when no known order—e.g., a stratigraphic sequence—exists, and especially if site durations are relatively short. Using the reversal/plateau AD 1480–1630 and the archaeology of northeastern North America as our example, we consider possible strategies to improve chronological resolution across such reversal/plateau periods in the absence of stratigraphic sequences, including uses of wood-charcoal TPQs from even very short wiggle-matches, and site phase duration constraints based on ethnohistoric and archaeological evidence.
  3. Biehl, Peter F. (Ed.)
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Although the igneous penetration was only two-thirds of the planned amount, drilling during Expedition 391 obtained samples that clearly will lead to a deeper understanding of the evolution of the Tristan-Gough hotspot and its track. Relatively fresh basalts with good recovery will provide ample samples for geochemical, geochronologic, and paleomagnetic studies. Good recovery of Late Cretaceous and early Cenozoic chalk successions provides samples for paleoenvironmental study.« less