Article

A 14C age calibration curve for the last 60 ka: the Greenland-Hulu U/Th timescale and its impact on understanding the Middle to Upper Paleolithic transition in Western Eurasia

Universität zu Köln, Institut für Ur- und Frühgeschichte, Radiocarbon Laboratory, Weyertal 125, 50923 Köln, Germany.
Journal of Human Evolution (Impact Factor: 3.87). 11/2008; 55(5):772-81. DOI: 10.1016/j.jhevol.2008.08.017
Source: PubMed

ABSTRACT This paper combines the data sets available today for 14C-age calibration of the last 60 ka. By stepwise synchronization of paleoclimate signatures, each of these sets of 14C-ages is compared with the U/Th-dated Chinese Hulu Cave speleothem records, which shows global paleoclimate change in high temporal resolution. By this synchronization we have established an absolute-dated Greenland-Hulu chronological framework, against which global paleoclimate data can be referenced, extending the 14C-age calibration curve back to the limits of the radiocarbon method. Based on this new, U/Th-based Greenland(Hulu) chronology, we confirm that the radiocarbon timescale underestimates calendar ages by several thousand years during most of Oxygen Isotope Stage 3. Major atmospheric 14C variations are observed for the period of the Middle to Upper Paleolithic transition, which has significant implications for dating the demise of the last Neandertals. The early part of "the transition" (with 14C ages > 35.0 ka 14C BP) coincides with the Laschamp geomagnetic excursion. This period is characterized by highly-elevated atmospheric 14C levels. The following period ca. 35.0-32.5 ka 14C BP shows a series of distinct large-scale 14C age inversions and extended plateaus. In consequence, individual archaeological 14C dates older than 35.0 ka 14C BP can be age-calibrated with relatively high precision, while individual dates in the interval 35.0-32.5 ka 14C BP are subject to large systematic age-'distortions,' and chronologies based on large data sets will show apparent age-overlaps of up to ca. 5,000 cal years. Nevertheless, the observed variations in past 14C levels are not as extreme as previously proposed ("Middle to Upper Paleolithic dating anomaly"), and the new chronological framework leaves ample room for application of radiocarbon dating in the age-range 45.0-25.0 ka 14C BP at high temporal resolution.

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    • "The current standard estimate of r(t) for atmospheric Northern Hemisphere organic samples is the INTCAL13 calibration curve, and it extends close to the practical limits of radiocarbon dating, 50,000 cal BP (Niu, 2013; Ramsey et al., 2013; Reimer et al., 2013; Staff, 2013). A second r(t) estimate is the CalPal-Hulu 2007 curve, which includes much of the radiometric data included in the INTCAL13 curve, using simple cubic spline interpolation between radiometric data points throughout its length (Weninger and J€ oris, 2008). We used the CalPal-Hulu 2007 curve to extend our calibration dataset from 50,001 to 59,500 cal BP. "
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    • ". The laboratory protocols used by Maroto et al. (2012) include rigorous sample pre-treatment to minimize contamination of samples. For calibration the CalPal-2007-Hulu data set (Weninger and Jöris, 2008) and the CalPal software package (Weninger et al., 2008) were used. "
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