• Editorial Board

      Department of Geosciences, The University of Arizona, 2001-01-01
    • Environmental Influences on Dietary Carbon and 14C Ages in Modern Rats and Other Species

      Beavan-Athfield, Nancy R.; McFadgen, Bruce G.; Sparks, Rodger J. (Department of Geosciences, The University of Arizona, 2001-01-01)
      Diet can play a significant role in anomalous radiocarbon ages derived from bone and other tissues when the food web incorporates depleted 14C reservoirs, such as the marine environment. Dietary effects from a post-bomb carbon variation have also been found in modern invertebrates and populations of Rattus exulans (Beavan and Sparks 1998). We now present the effect on absolute percent modern (pMC) and the conventional radiocarbon age (CRA) of a modern aquatic/terrestrial food web in a volcanic zone of the North Island, New Zealand. At Lake Taupo, geothermal venting transfers 14C depleted carbon to lake waters, which aquatic plants fix into the food chain; depleted 14C is shown to then pass on to shellfish, waterfowl, and Norway rat (Rattus norvegicus). The geothermally induced 14C variations from modern atmospheric p MC andCRA can increase apparent 14C ages by >2000 years.
    • Estimation of Inbuilt Age in Radiocarbon Ages of Soil Charcoal for Fire History Studies

      Gavin, Daniel G. (Department of Geosciences, The University of Arizona, 2001-01-01)
      Radiocarbon age determinations of wood charcoal are commonly used to date past forest fire events, even though such ages should be greater than the fire event due to the age of the wood at the time of burning. The difference in the 14C-derived age of charcoal and the time-since-fire (the "inbuilt age") may be considerable in some vegetation types and thus must be estimated before interpreting fire dates. Two methods were used to estimate the potential range of inbuilt age of soil charcoal dated to determine ages of forest fires on the west coast of Vancouver Island (Canada). First, 26 14C ages on charcoal in surficial soil were compared directly with ages of forest fire determined by tree-ring counts, suggesting inbuilt ages of 0-670 years. Second, a simulation model that uses estimated fuel loads, fuel consumption, charcoal production, and the ages of charred wood (time since wood formation), suggests that the combination of slow growth rates and slow decay rates of certain species can account for inbuilt ages of more than 400 years in this forest type. This level of inbuilt age is large enough such that the actual age of a fire may not occur within the 2sigma confidence interval of a calibrated charcoal 14C age determination, and thus significantly affect the interpretation of fire dates. A method is presented to combine the error of a calibrated 14C age determination with the error due to inbuilt age such that the larger adjusted error encompasses the actual age of the fire.
    • From the Editor

      Jull, A. J. T. (Department of Geosciences, The University of Arizona, 2001-01-01)
    • Least-Squares Fitting Smooth Curves to Decadal Radiocarbon Calibration Data from AD 1145 to AD 1945

      Knox, F. B.; McFadgen, B. G. (Department of Geosciences, The University of Arizona, 2001-01-01)
      Smoothed curves are least-squares fitted to three sets of decadal radiocarbon calibration data from New Zealand and British Isles (AD 1725-1935) and western North America (AD 1145-1945). The curves are compared with each other and with a curve previously calculated from New Zealand data (AD 1335-1745). The smoothing procedure results in reduced standard deviations of the curves, but at the expense of time resolution. The comparison shows a variable 14C offset between the northern and southern hemispheres of 0-70 years (Southern Hemisphere older), and a Northern Hemisphere longitudinal variation of -20 to +60 years (British Isles generally older than western North America).
    • Libby and the Interdisciplinary Aspect of Radiocarbon Dating

      de Messières, Nicole (Department of Geosciences, The University of Arizona, 2001-01-01)
      At a time when exchange between scientific and non-scientific disciplines was uncommon, Willard F. Libby broke through conventional barriers. Early influences prepared him for a career marked by its interdisciplinary approach, and for a discovery with far-ranging applications to many diverse branches of knowledge.
    • Radiocarbon Determinations from the Mulifanua Lapita Site, Upolu, Western Samoa

      Petchey, Fiona J. (Department of Geosciences, The University of Arizona, 2001-01-01)
      The Mulifanua ferry berth has the distinction of being the only site in Samoa with dentate-stamped Lapita wares, and is the most easterly Lapita site in the Pacific. Two new radiocarbon determinations of material associated with Lapita pottery found at Mulifanua are presented. The accuracy of this data is evaluated according to the results of recent re-assessment of pottery from the site, and current theories regarding the age of Lapita settlement in the eastern Pacific. The resulting calibrated radiocarbon ages put occupation of the Mulifanua Lapita site at around 2880-2750 cal BP (930-800 BC). This conclusion is in agreement with the pottery chronology and supports recent hypotheses of rapid Lapita settlement in the Fiji/Tonga region around 2850-2700 cal BP (900-750 BC).
    • Radiocarbon, Volume 43, Number 1 (2001)

      Department of Geosciences, The University of Arizona, 2001-01-01
    • Renee Kra (1936-2001)

      Elliott, Kim (Department of Geosciences, The University of Arizona, 2001-01-01)
    • Reservoir Offset Models for Radiocarbon Calibration

      Jones, Martin; Nicholls, Geoff (Department of Geosciences, The University of Arizona, 2001-01-01)
      The purpose of a reservoir offset is to enable the application of calibration data (mu (theta), 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.
    • Suitability of Ostrich Eggshell for Radiocarbon Dating

      Vogel, John C.; Visser, Ebbie; Fuls, Annemarie (Department of Geosciences, The University of Arizona, 2001-01-01)
      Ostrich eggshell from archaeological sites remains largely free of more recent carbon contamination and as such is suitable material for radiocarbon dating. The carbonate fraction of the shell does, however, display an initial deficit in 14C, which causes the ages to appear 180 +/120 yr too old.
    • The 4300-Yr 14C Age of Glyptodonts at Luján River (Mercedes, Buenos Aires, Argentina) and Comments on 'Did the Megafauna Range to 4300 BP in South America' by Cione et al.

      Rossello, Eduardo A.; Jahn, Bor-ming; Liu, Tsung-Kwei; Petrocelli, Jorge L. (Department of Geosciences, The University of Arizona, 2001-01-01)
    • The Effects of Possible Contamination on the Radiocarbon Dating of the Dead Sea Scrolls I: Castor Oil

      Rasmussen, Kaare L.; van der Plicht, Johannes; Cryer, Frederick H.; Doudna, Gregory; Cross, Frank M.; Strugnell, John (Department of Geosciences, The University of Arizona, 2001-01-01)
      Some fragments of the Dead Sea Scroll manuscripts were contaminated with castor oil in the late 1950s. We have conducted experiments in order to establish if the AAA pretreatment cleaning procedures conducted on Dead Sea Scroll manuscript samples in the last two dating series (Bonani et al. 1992; Jull et al. 1995) were effective in removing oil contamination. Our experiments show that not all oil contamination can be expected to have been removed by the acid-alkaline-acid (AAA) pretreatment, and that the radiocarbon ages previously reported therefore cannot be guaranteed to be correct. Any samples contaminated with castor oil were most likely reported with ages that are too young by an unknown amount.
    • The First Paper About Exciting of Fluorescence of Liquid Biphenyl and Phenanthren by Fast Electrons by Lieselott Herforth and Hartmut Kallmann

      Niese, S. (Department of Geosciences, The University of Arizona, 2001-01-01)
      The first measurements of the fluorescence of liquid organic compounds after excitation with nuclear radiation were published 1948 in a thesis of L. Herforth and a paper by Herforth and Kallmann (1949).