With one exception, the radiocarbon dates in this list were reported previously by Rainey and Ralph (1959). For discussions of the reliability of the dates, of the materials dated, and of the correspondence of the dates with estimated arctic chronologies, the reader is urged to refer to the original publication. The radiocarbon determinations were made over a period of several years. Those processed before 1956 were dated by the solid-carbon method and are so labeled; others, by the carbon-dioxide method. The age calculations are based on the average of several samples dated archaeologically and by tree-rings, corrected to zero age (Rainey and Ralph, 1959, p. 365). By this means the errors due to atmospheric depletion (Suess effect) and to past changes in radiocarbon concentration (de Vries, 1958; Willis, Tauber, and Münnich, 1960) have been minimized. The b.p. dates are calculated from A.D. 1957 (solid-carbon) and A.D. 1958 (carbon dioxide).

The small but vital role of 14C dating in archaeometric research is clearly shown in the copper project reported herein. The 14C ages place a time perspective on the “Old Copper Culture Complex,” substantiating early Libby dates that had been questioned. The respective roles of INAA, PGE and Pb isotope work are briefly summarized. A long tradition of heat treatment from Paleoindian stone to Archaic copper is suggested.

The Laboratoire des Sciences du Climat et de l'Environnement (LSCE) research program on prehistoric art conducts chronological studies of parietal representations with their associated archaeological context. This multidisciplinary approach provides chronological arguments about the creation period of parietal representations. This article presents chronological investigations carried out in several decorated caves in France (La Grande Grotte, Labastide, Lascaux, La Tête-du-Lion, Villars) and Spain (La Garma, Nerja, La Pileta, Urdiales). Several types of organic materials, collected from different areas of the caves close to the walls and in connection with parietal art, were dated to determine the periods of human presence in the cave, a presence that may have been related to artistic activities. These new radiocarbon results range from 33,000–29,000 (La Grande Grotte) to 16,000–14,000 cal BP (Urdiales).

Radiocarbon (14C) dating of anthropogenic carbonates (CaCO3) such as ash, lime plaster and lime mortar, has proven a difficult task due to the occurrence of a number of contaminants embedded within the CaCO3 pyrogenic binder. These include 14C-free geologic components and/or secondary phases bearing an unknown amount of 14C, and thus the alteration of the original pyrogenic isotopic signature of the material results in major age offsets when carbon recovery is performed through acid hydrolysis. Here we present a characterization/quantification approach to anthropogenic carbonates that includes Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thin section petrography, thermogravimetric analysis and scanning electron microscopy coupled with high-resolution cathodoluminescence, with which we identified the pyrogenic CaCO3 fraction in an aerial lime plaster and two hydraulic mortars. The preserved pyrogenic component was then isolated by density separation and its purity checked again using FTIR. Carbon was recovered through thermal decomposition in vacuum. The resulting 14C age matches the expected age of the lime plaster, whereas hydraulic mortars are slightly offset due to the carbonation of calcium hydroxide lumps. This approach highlights the importance of a dedicated characterization strategy prior to dating and may be applied to aerial lime plasters to obtain accurate ages.

We performed a statistical analysis of the data on summer temperature anomalies in northern Fennoscandia (8–1995 AD) and found that a 70–130-yr cycle is present in this series during most of the time period. A comparison of the reconstructed northern Fennoscandia temperature with different indicators of solar activity (Wolf numbers, the length of solar Schwabe cycle, extended bi-decadal radiocarbon series, and data on sunspots observed by naked eye) shows that the more probable cause of the periodicity is the modulation of regional northern Fennoscandia climate by the long-term solar cycle of Gleissberg. The effect of this century-scale solar modulation of the global Northern Hemisphere temperature is weaker.

We show that smoothed versions of the high-resolution calibration curve should be used when 14C ages are calibrated with large (> ∼30 14C yr) measurement errors (represented by standard deviation δm) or are mixtures of elements of variable age (natural sample error with standard deviation δn). The degree of smoothing should agree with the standard deviation of total sample error, δt, the square root of the quadratic sum of δm and δn. However, in most cases, δt is not well known, especially due to difficulties in quantifying δn. We present an inverse method that gives a measure of mean δt, for different materials that are widely used in (conventional) 14C dating. Calculations with large (>100) data sets of wood, charcoal, ombrotrophic peat and minerotrophic peat/gyttja samples indicate that δt of such materials is generally much larger than previously assumed, mainly because of large values of δn. This means that particularly in organic deposits, strongly smoothed calibration curves should be used where medium-term 14C variations (wiggles) are completely straightened. This has especially major consequences for calibrating 14C histograms for natural 14C variations. We conclude that 14C histograms consisting of samples of organic deposits do not require correction for medium-term 14C variations and that uncalibrated 14C histograms need not be as suspect as is usually believed.

The following list comprises age measurements carried out between December 1963 and September 1964. The samples dated are almost all of archaeological interest and are drawn from Italian and Egyptian territory.

The first application of U-series dating and accelerator mass spectrometry (AMS) assay of Polynesian archaeological Pocillopora spp. branch corals for deriving a precise local marine reservoir correction (ΔR) is described. Known-age corals were selected that spanned the entire culture-historical sequence for the Hawaiian Islands, thus eliminating the problem of not having known-age dated samples that cover the period of direct relevance to prehistorians; in this case, about AD 700–1800. Dating coral samples from windward and leeward coastlines of Moloka'i Island, with different offshore conditions such as upwelling, currents, wind patterns, coastal topography, and straight or embayed shorelines, provides insights into possible variations of local conditions on the same island—something that has never been attempted. In this regard, there was no spatial variability in ΔR during the 17th century. We report a weighted average ΔR value for Moloka'i Island of 52 ± 25 yr using 12 pair-dated dedicatory branch corals from religious archaeological sites and demonstrate that there is no significant temporal variability in ΔR between about AD 700 to 1800. In combination with 4 selected previously published ΔR values based on pre-bomb known-age marine shells, a revised ΔR of 66 ± 54 yr is established for the Hawaiian Islands. However, future research should examine the archipelago-wide spatial variability in ΔR with the analysis of additional dated archaeological coral samples.

Recent fieldwork by the Industries of Angkor Project (INDAP) has identified the first extensive evidence of iron production within an Angkorian Khmer (9th to 15th centuries AD) center at Preah Khan of Kompong Svay (Preah Khan) in Preah Vihear province, Cambodia. This immense 22-km2 temple complex appears to be an outpost of Khmer settlement situated in close proximity to Phnom Dek (“Iron Mountain”), the richest known source of iron oxide in Cambodia. Combined with the fact that Preah Khan's temple architecture dates between the late 10th to early 13th centuries, the period that the Khmer greatly expanded their territorial influence, our primary hypothesis is that this complex was established to gain access to and monitor production of iron for the capital of Angkor. The vast number and size of these iron slag concentrations, some up to 5 m in height by 35 m in length, precludes the use of traditional excavation and dating methods. Instead, this paper employs 14C dating of “in-slag” charcoal from surface slag cakes to produce a spatial chronology of late or “terminal” industrial activities. The results indicate that metallurgy was “last” practiced at various locations within Preah Khan in the mid-13th to late 17th centuries, with 3 distinct clusters between the late 13th and late 15th centuries. Based on this initial survey of surface collections, it appears that iron production at Preah Khan occurred after the final phase of masonry construction. More significantly, this work provides the first robust set of dates for late Angkorian and Middle period industrial activities in Cambodia.

Detailed radiocarbon chronologies from three volcanic crater lakes (maars) in southeast Australia are examined in relationship to the magnetic mineral stratigraphies within lakes, and the magnetic secular variation stratigraphy between lakes. Some implications for magnetic dating are considered.

Lacustrine sediments are important archives for paleoclimate research, but there are evident carbon reservoir effects. Radiocarbon (14C) ages of lake sediments must be corrected for these effects before applying them to paleoclimate research. The authors review the lacustrine research from the last 20 years from different climatic regions in China, and systematically investigate the 14C age and correction methods used in the studies of 81 lakes. It is found that the climate-vegetation cover and distribution of carbonate around lakes are dominant factor controlling radiocarbon reservoir effects. In eastern China, the average 14C reservoir age is about 500 14C years and is associated with relatively dense vegetation. However, in northwest China and Qinghai-Tibet Plateau, widespread carbonate bedrock may markedly increase the radiocarbon reservoir age which frequently is about 1500 and 2500 14C years. A piecewise linear regression model provides more reliable 14C reservoir age correction that accounts for sedimentary facies and sedimentation rate changes. It is worth mentioning that when analyzing 14C ages deviated greatly from time sequence, the age anomalies may indicate important effects relevant to the study of climate and environmental changes.

The SMU Radiocarbon Laboratory is operated by the Department of Geological Sciences within the Institute for the Study of Earth and Man. One laboratory room contains the benzene synthesis system where samples are pretreated and converted to CO2 in a standard way and gas is purified after the procedures of Broecker (1957) by passage through hot CuO, 10% AgNO3 solution, chromic acid, hot copper, and P2O5 via cryogenic pumping with liquid nitrogen. Purified CO2 is then converted to Li2C2 which is hydrolized to C2H2 and converted to C6H6 catalytically following the procedures of Noakes et al (1966). Carbon dioxide and benzene yields are routinely in excess of 90% in both cases.

Micro-ampere beams of C– have been produced with the Aarhus negative-ion source, operated on CO2 gas. The efficiency of the source and memory effects have been measured, using 13C-enriched CO2, in order to evaluate the applicability of the source to 14C dating by accelerator mass spectroscopy.

Recent fieldwork on the island of Faial (Azores) led to the establishment of a detailed volcanic stratigraphic sequence, which is composed of five main geological formations. One of them, the Caldeira Formation, comprising mainly pumice fall and flow deposits, was judged to be Holocene in age. Organic materials were found preserved in or below some of the pyroclastic deposits from this formation. Wood, charcoal, peat and soil samples were radiocarbon dated, permitting correlation of deposits from different sequences and the establishment of a chronological framework for the Caldeira volcanic activity. These materials yielded ages from ca. 10–1 ka bp. The average dormant interval in the Caldeira pyroclastic activity from 4–1 ka ago is ca. 400 yr, with eruptions approximately every 200–800 yr. This frequency of activity indicates that the Caldeira volcano is an active, dangerous structure that should be closely monitored.

The following list includes 14C measurements of geologic samples, the majority of which pertain to sea-level variations, and of archaeologic samples mainly from France, West Africa, and South America. Most of the dates were measured between 1972 and 1973 when installations were not modified. The technique used is described in Radiocarbon, 1972, v 14, p 280–320. Dates were calculated using the 14C half-life of 5568 years; modern standard is 0.95 of the NBS oxalic acid. Reported errors are one standard deviation for 2000 minutes measurements.

A new sealed double tube combustion method was developed at Lawrence Livermore National Laboratory (LLNL) to extract carbon from modern steels and ancient iron artifacts. Iron samples were chemically pretreated with 10% nitric acid, vacuum sealed in 6 mm quartz tubes with CuO, vacuum sealed again inside 9 mm quartz tubes, and combusted at 1000 °C for a minimum of 10 hr. The resulting CO2 was graphitized routinely using hydrogen reduction (Vogel et al. 1989). After the initial phase of development, carbon yields of 100% were consistently obtained. The activities of two modern high carbon steels (treated as process blanks, manufactured using only coal as the carbon source) were determined to be 0.0077 ± 0.0009 (n = 12, ± 1 σ) for a 1.3% C steel and 0.0090 ± 0.0038 (n = 12, ± 1 σ) for a 1.9% C steel, indicating that very little contamination is introduced during the sample preparation process. Since the Iron Age began less than 5000 years ago, these background uncertainties should introduce errors of no more than ±30 years to the radiocarbon ages of actual artifacts. Two ancient iron artifacts of known date were analyzed and demonstrate that the new methodology can be used to obtain the correct date of manufacture for iron objects, provided that they are made exclusively using charcoal that was contemporaneous with the manufacture of the artifact. Since only 1 mg of carbon is required for accelerator mass spectrometry (AMS), very small iron samples can now be analyzed (50 mg of a 2.0% C iron or 1 g of a 0.1% C iron). We anticipate that this methodology will be particularly useful to archeologists who currently have to rely on context to date iron artifacts.

Atmospheric 14C variations in nature, as previously documented for the Southern Hemisphere by studies carried out in South Africa and New Zealand, were supplemented by 14C concentration measurements of wheat-grain samples collected in southeastern New South Wales. Our measurements cover the critical period of 1945/46 up to 1956/57, and span the transition of Suess and atom-bomb effects. The observed variations can be followed quite precisely in the peat deposits of the Bega Swamp, New South Wales, and indicate that vertical mixing of organic components within the peat is negligible. Pollen analytical data covering the last 400 years also show that the peats act as efficient traps; thus, time-precise zonations can be identified, and historically documented man-induced changes in pollen assemblages can be correlated with 14C ages in recent times.

Often it is not possible to date a sample of wood from the final growth ring of the tree from which it came. In these cases, an “old-wood offset” is apparent. A number of quantitative approaches for the assessment of this offset are available, dependent on the actual tree rings that have been dated. A range of examples are given, demonstrating how such radiocarbon measurements can be interpreted using additional information from archaeology and dendrochronology.

At the University of Miami Tritium Laboratory and the University of Washington Quaternary Isotope Laboratory, more than 1000 large-volume Pacific Ocean radiocarbon samples were measured for the WOCE program. Here we present a comprehensive data set, and a brief discussion of our findings.

Ust’-Polui is one of the most extensively studied archaeological sites in the western Siberian Arctic. New radiocarbon (14C) dates for charcoal, faunal remains, bark, hide, and human bone from this site are presented. When modeled, the charcoal dates span from ~260 BC to 140 AD, overlapping with the dendrochronology dates from the site. These dates also overlap with the expected age of the site based on artefact typology. 14C dates on reindeer bone have a slightly younger modeled age range, from ~110 BC to 350 AD. In contrast, dates on the site’s numerous dog remains, and on human and fish bone, all predate these modeled age ranges by over 500 years, despite being from the same deposits. Several sets of paired dates demonstrate significant age differences. Bone dates with lower δ13C values tend to be over 500 years older than those with higher δ13C values. Stable isotope data for the humans, dogs, and other faunal remains are also presented. These data suggest the dogs and the humans were regularly consuming freshwater fish. The dogs were probably fed fish by their human counterparts. Overall, the dog and human dietary patterns at Ust’-Polui created 14C dates biased with major freshwater reservoir effects.