Acerbic, abusive, brilliant, brusque, eclectic, exasperating, insightful, irritating, patient, patronizing, gentleman—these are but a few of the terms I have heard applied to Bob Stuckenrath over the 24-year period that I knew him. Their contradictory diversity serves to capture, if not the essence, at least some of his many different facets as a man and scholar.

This paper proposes the use of the statistical bootstrap technique as an aid in combining radiocarbon date estimates The rationale for the use of the bootstrap is the theoretical result that, even if individual date estimates are normally distributed, their combination by the usual formula results in a random quantity that is not normal but rather a mixture of distributions. The bootstrap is a non-parametric, computer-intensive technique. This technique can better estimate the actual distribution of the combined age, leading to more precise confidence intervals. While the bootstrap cannot solve the multiple-intercepts problem in calibration, it can nonetheless lead to better estimates. The benefits of using the bootstrap are especially noticeable when sample sizes are small (as is the case in other applications of this technique).

An approximate randomization technique for comparing 14C histograms is described and illustrated with an example from Hawai'i. The technique determines intervals of significant difference in the histograms, rather than providing a single number summary.

Radiocarbon dating results of mammoth tusks, teeth and bones collected on Wrangel Island between 1989 and 1991 reveal a unique mammoth refugium during the Holocene. We used an improved chemical procedure to obtain and purify collagen from bone. Benzene synthesized from the samples was measured using a liquid scintillation counter. The validity of our data has been confirmed by the results of our measurements on two international control sample series (IAEA and TIRI) and by parallel measurements of Wrangel Island mammoth remains at other laboratories.

A harvest of 300 radiocarbon dates on extinct elephants (Proboscidea) from the northern parts of the New and Old Worlds has revealed a striking difference. While catastrophic in North America, elephant extinction was gradual in Eurasia (Stuart 1991), where straight-tusked elephants (Palaeoloxodon antiquus) vanished 50 millennia or more before woolly mammoths (Mammuthus primigenius). The range of the woolly mammoths started shrinking before 20 ka ago (Vartanyan et al. 1995). By 12 ka bp, the beasts were very scarce or absent in western Europe. Until the dating of Wrangel Island tusks and teeth (Vartanyan, Garrutt and Sher 1993), mammoths appeared to make their last stand on the Arctic coast of Siberia ca. 10 ka bp. The Wrangel Island find of dwarf mammoths by Sergy Vartanyan, V. E. Garrut and Andrei Sher (1993) stretched the extinction chronology of mammoths another 6 ka, into the time of the pharaohs.

We discuss a vacuum-distillation method for obtaining representative 14C samples from dissolved inorganic carbon in rock pore-waters. Distillation offers four advantages over current centrifugation and compression methods for obtaining pore-water carbon: 1) carbon recovery is possible from rocks that will not yield water by centrifugation or compression; 2) the mass required for 14C analysis can typically be obtained in a single extraction, eliminating the need for storing and combining multiple pore-water collections; 3) water and carbon are extracted and isolated simultaneously, reducing the number of required steps and the potential for contamination; and 4) distillation requires less equipment at lower cost than centrifugation or compression. In this study, isotopic fractionation resulting from incomplete recovery of carbon during distillation was too high for stable isotope applications, but was relatively minor for 14C applications. The lighter isotopes were favored in the recovered phase, resulting in samples depleted in 14C by a maximum of 4%. Mass balance calculations indicate that there may be a significant reservoir of carbon absorbed to mineral surfaces that is only partially removed by this method. Incorporation of adsorbed carbon into the recovered sample did not measurably alter the 14C activity.

We compared accelerator mass spectrometry (AMS) 14C ages of large (>150 μm) pelagic foraminifera with radiometric bulk carbonate 14C ages in two northeastern Atlantic cores. The foraminiferal ages are consistently older than those of the bulk sediment (by + 0.76 ka in Core 11881 and by + 1.1 ka in Core 11886), whereas corresponding fine (<5 μm) fraction ages are similar to those of the bulk sediment carbonate. We calculated near-identical sediment accumulation rates from both the foraminiferal and bulk sediment age/depth relations (3.0 cm ka−1 in Core 11881 and 5.9 cm ka−1 in Core 11886). Consideration of various factors that might produce such offsets leads us to believe that they are not artifacts, but were most probably caused by differential bioturbation of the different size-fractions in the sediment surface mixed layer. The importance of this finding is that many paleoceanographic records, such as the oxygen isotope record, also derive from analyses of large foraminifera, so that these records must be offset in time from the bulk of the sediments that they characterize.

We report on new 14C measurements of samples of 18 texts (scrolls) and 2 linen fragments from Qumran Caves 1, 2, and 4 and from Nahal Hever, both in the Dead Sea region. The radiocarbon results are in good agreement with estimates of age based on paleography.

AMS 14C dates were measured for 28 mollusk shells collected live in Danish waters over the period ad 1885 to 1945. Fourteen samples were from fjords and 14 were marine samples from the Danish Skagerrak-Kattegat coastal area and from the Belts. Reservoir ages were calculated for all samples on the basis of the tree-ring calibration curve. For the marine samples, which cover the period ad 1885–1916, we found a weighted-average reservoir age of 377 ± 16 yr. The marine ∆R values (the difference between the measured 14C age and the age deduced from marine, mixed-layer model calculation of Stuiver, Pearson and Braziunas (1986)) were found to be uniform within the experimental uncertainty with a weighted average of ∆R = 13 ± 16 yr. Based on the observed scatter, the standard deviation is 21 yr. This result shows that it is justified to use the marine calibration curve with standard parameters (∆R = 0) when 14C-dating marine samples from the Danish area. Our value is consistent with the result ∆R = −33 ± 27 yr previously found for the Norwegian and Swedish Skagerrak-Kattegat coasts. In contrast, reservoir ages for Danish fjords were found to vary from 400 to >900 yr, far beyond experimental uncertainty. We ascribe this to varying content of dissolved, old soil carbonate (hard-water effect). Therefore, dating of samples from such fjord environments is expected to be uncertain by several hundred years.

Radiocarbon was measured in atmospheric CO2 from La Jolla, California and in living organic materials from six sites in the northern hemisphere. Atmospheric CO2 ∆14C values from La Jolla agreed with those previously published records from China Lake, California (Berger et al. 1987) and Vermunt, Austria (Levin et al. 1985). ∆14C values of fruit and grain samples that grew during 1980 agreed with the atmospheric CO2 ∆14C measurements. Most of the ∆14C results of fruit and corn samples stored since the 1940s agreed with tree-ring ∆14C values for the same time period. In general, agreement was found between the atmospheric CO2 or tree-ring ∆14C records available for the Northern Hemisphere and the ∆14C signatures of rapidly exchanging organic matter pools examined in this study. Exceptions were the ∆14C values of carbonate from egg shells and that of organic carbon from egg insides, which demonstrate that bicarbonate and organic carbon within the egg follow different biochemical pathways.

The Dead Sea Scrolls have been analyzed by paleographic, non-destructive and destructive testing. The dates of their creation have been in dispute since their discovery. Research has established their authenticity, but a variety of conditions including the methods of skin preparation, variation in storage conditions and post-discovery restoration treatments could have introduced changes now affecting dating efforts. Comprehensive analyses were not possible until recently. Such analysis must be performed to establish a concrete framework for all the texts.

Professor R. B. Blake told a story in response to a question of why so little remained of writing on leather. He said that on one of his expeditions to Asia Minor, one of his native servants exhibited proudly some chamois trousers of his own manufacture, upon which Professor Blake detected with sorrow, traces of medieval writing (Reed 1972).