Hostname: page-component-8448b6f56d-mp689 Total loading time: 0 Render date: 2024-04-19T20:33:47.873Z Has data issue: false hasContentIssue false

Reservoir Offset Models for Radiocarbon Calibration

Published online by Cambridge University Press:  18 July 2016

Martin Jones
Affiliation:
Centre for Archaeological Research, University of Auckland, Private Bag 92019, Auckland, New Zealand. Email: Martin@analytic.co.nz.
Geoff Nicholls
Affiliation:
Department of Mathematics, University of Auckland, Private Bag 92019, Auckland, New Zealand. Email: Nicholls@math.auckland.ac.nz.
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The purpose of a reservoir offset is to enable the application of calibration data (μ(θ), e.g. Stuiver et al. 1998) developed for one reservoir (primary reservoir) to CRAs from another (secondary reservoir), for example the use of a hemispheric offset for terrestrial samples (Barbetti et al. 1995; McCormac et al. 1998; Sparks et al. 1995; Vogel et al. 1986, 1993). The usual approach has been to define the activity of the secondary reservoir as some form of constant offset (with error) from the primary reservoir (e.g. Higham and Hogg 1985; McFadgen and Manning 1990). In this case, all CRAs from a secondary reservoir are given the same offset. The value of this common offset is not known exactly, but any uncertainty in the measured value of the offset corresponds to uncertainty in the common offset for all CRAs. However, the standard procedure for incorporating offset error into CRAs incorrectly allows a different offset for each CRA. The offset for each CRA is incorrectly allowed to vary by the measurement error reported for the offset value. Technically, the offset is incorrectly treated as varying independently from one CRA to the next, when in fact it is a single parameter for the secondary reservoir in question. In light of this, the calibrated date distributions will be incorrect for CRAs where an offset has been applied and the standard approach to offset error treatment has been used. In many cases, the differences between correct and incorrect calibrated date distributions will be insignificant. However, in some cases significant differences may arise and other approaches to treating the error associated with offsets need to be adopted.

Type
Notes and Technical Comments
Copyright
Copyright © The Arizona Board of Regents on behalf of the University of Arizona 

References

Anderson, AJ, Smith, IWG, Higham, TFG. 1996. Radiocarbon chronology. In: Anderson, AJ, Allingham, B, Smith, IWG, editors, Shag River Mouth: the archaeology of an early Southern Maori village. Volume 27. Canberra, Australia: ANH Publications, RSPAS, ANU. p 60–9.Google Scholar
Barbetti, M, Bird, T, Dolezal, G, Taylor, G, Francey, R, Cook, E, Petersen, M. 1995. Radiocarbon variations from tasmanian conifers: results from three holocene logs. Radiocarbon 37(2):361–9.Google Scholar
Buck, C, Cavanagh, W, Litton, C. 1996. Bayesian approach to interpreting archaeological data. Chichester: Wiley.Google Scholar
Buck, C, Christen, J, James, G. 1999. Bcal: an online bayesian radiocarbon calibration tool. Internet Archaeology 7. http://intarch.ac.uk.Google Scholar
Christen, A, Nicholls, G. 2000. Random-walk radiocarbon calibration. Technical report 457. Mathematics Department, Auckland University, New Zealand. http://www.math.auckland.ac.nz/≃nicholls.Google Scholar
Higham, TFG, Hogg, AG 1995. Radiocarbon dating of prehistoric shell from New Zealand and calculation of the δr value using fish otoliths. Radiocarbon 37(2): 409–16.CrossRefGoogle Scholar
Jones, M, Nicholls, GK. 1999. Datelab: new date analysis software. http://www.car.auckland.ac.nz. In preparation.Google Scholar
McCormac, FG, Hogg, AC, Higham, TFG, Baillie, MGL, Palmer, JG, Xiong, L, Pilcher, JR, Brown, D, Hoper, ST. 1998. Variations of radiocarbon in tree-rings: Southern Hemisphere offset preliminary results. Radiocarbon 40(3):1153.Google Scholar
McFadgen, BG, Manning, MR. 1990. Calibrating New Zealand radiocarbon dates of marine shells. Radiocarbon 32(2):229–32.Google Scholar
Nicholls, GK, Jones, MD. 1998. Radiocarbon dating with temporal order constraints. Technical report 407. Mathematics Department, Auckland University, New Zealand. http://www.math.auckland.ac.nz/≃nicholls.Google Scholar
Ramsey, CB. 1995. Radiocarbon calibration and analysis of stratigraphy: the OxCal program. Radiocarbon 37(2):425–30.Google Scholar
Sparks, R, Melhuish, W, McKee, J, Ogden, J, Palmer, J, Molloy, B. 1995. 14C calibration in the southern hemisphere and the date of the last Taupo eruption: evidence from tree ring sequences. Radiocarbon 37(2): 155–63.CrossRefGoogle Scholar
Stuiver, M, Braziunas, TF. 1993. Modeling atmospheric 14C influences and 14C ages of marine samples to 10,000 BC. Radiocarbon 35(1):137–91.Google Scholar
Stuiver, M, Reimer, PJ, Beck, JW, Bard, E, Burr, GS, Hughen, KA, Kromer, B, McCormac, FG, van der Plicht, J, Spurk, M. 1998. INTCAL98 radiocarbon age calibration, 24,000–0 cal BP. Radiocarbon 40(3):1041–83.Google Scholar
Vogel, JC, Fuls, A, Visser, E, Becker, B. 1986. Radiocarbon fluctuations during the third millennium BC. Radiocarbon 28(2A):935–8.Google Scholar
Vogel, JC, Fuls, A, Visser, E, Becker, B. 1993. Pretoria calibration curve for short lived samples, 1930–3350 BC. Radiocarbon 35(1):7385.Google Scholar