Browsing by Author "Blackwell, PG"

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    SHCal13 Southern Hemisphere calibration, 0–50,000 years cal BP
    (University Arizona Department Geosciences, 2016-02-09) Hogg, AG; Hua, Q; Blackwell, PG; Niu, M; Buck, CE; Guilderson, TP; Heaton, TJ; Palmer, JG; Reimer, PJ; Reimer, RW; Turney, CSM; Zimmerman, SRH
    The Southern Hemisphere SHCal04 radiocarbon calibration curve has been updated with the addition of new data sets extending measurements to 2145 cal BP and including the ANSTO Younger Dryas Huon pine data set. Outside the range of measured data, the curve is based upon the ern Hemisphere data sets as presented in IntCal13, with an interhemispheric offset averaging 43 ± 23 yr modeled by an autoregressive process to represent the short-term correlations in the offset. © 2013, by the Arizona Board of Regents on behalf of the University of Arizona.
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    SHCal20 Southern Hemisphere calibration, 0–55,000 years cal BP
    (Cambridge University Press, 2020-08-12) Hogg, AG; Heaton, TJ; Hua, Q; Palmer, JG; Turney, CSM; Southon, J; Bayliss, A; Blackwell, PG; Boswijk, G; Bronk Ramsey, C; Pearson, C; Petchey, F; Reimer, P; Wacker, L
    Early researchers of radiocarbon levels in Southern Hemisphere tree rings identified a variable North-South hemispheric offset, necessitating construction of a separate radiocarbon calibration curve for the South. We present here SHCal20, a revised calibration curve from 0–55,000 cal BP, based upon SHCal13 and fortified by the addition of 14 new tree-ring data sets in the 2140–0, 3520–3453, 3608–3590 and 13,140–11,375 cal BP time intervals. We detail the statistical approaches used for curve construction and present recommendations for the use of the Northern Hemisphere curve (IntCal20), the Southern Hemisphere curve (SHCal20) and suggest where application of an equal mixture of the curves might be more appropriate. Using our Bayesian spline with errors-in-variables methodology, and based upon a comparison of Southern Hemisphere tree-ring data compared with contemporaneous Northern Hemisphere data, we estimate the mean Southern Hemisphere offset to be 36 ± 27 14C yrs older. © 2020 by the Arizona Board of Regents on behalf of the University of Arizona. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.