This paper deals with radiocarbon determinations from the Middle Bronze Age site of Portella on the island of Salina (Aeolian Archipelago, Italy). The available 14C evidence is taken into account, in a simple Bayesian model, in order to explore the issue of the absolute chronology of both the settlement and the stage of the local cultural sequence to which Portella belongs. A high date is proposed for the start of the Aeolian (and Sicilian) Middle Bronze Age: 1556–1422 cal BC (95.4% confidence), with a a most likely (modal) date of about 1450 cal BC. Further, the analysis suggests that the Portella phase is likely to have been a very short one, with a span of 0–65 yr (68.2%) or 0–131 yr (95.4%). The archaeological implications are explored. The relation of these results to the evidence of ceramic phasing is also considered. Since Aegean datable ceramic imports are documented in Aeolian/Sicilian Middle Bronze Age contexts, the connection between Portella's chronology and the absolute dating of one of the Aegean phases (namely, Late Helladic IIIA1) is also investigated.

Archaeological surface surveys carried out near Salve in southern Italy led to the identification of about 90 stone mounds spread over an area of about 100 ha. Systematic archaeological investigations allowed to identify the mounds as funeral structures with some having megalithic features. In the necropolis, both the inhumation and cremation rituals are evident, in some cases within the same mound. This article presents the results of an accelerator mass spectrometry (AMS) radiocarbon dating campaign carried out on different kinds of samples recovered from several structures: unburned and cremated bones, charcoals, and organic residues extracted from pottery sherds. The results allowed to assess the chronology of the site and to shed new light on the different funeral practices in Copper Age southern Italy.

The Radioisotopes Laboratory was established in January 1972, in order to supply radiocarbon measurements of various samples to several institutions. Active analyses commenced in June following the testing and evaluation of equipment and known samples for accuracy and reproducibility. During this time, data was accumulated for the statistical establishment of counting accuracy, particularly for background activity.

The freshwater reservoir effect (FRE) hypothesis suggests that ancient carbon from aquatic organisms incorporated into AMS-dated charred, encrusted cooking residues on interior pottery walls produces old apparent radiocarbon ages. This hypothesis has been used primarily in northern European final Mesolithic contexts to explain 14C ages on cooking residues that are thought to be too old relative to 14C ages obtained on terrestrial samples, resulting in so-called freshwater reservoir offsets (FROs). More recently, the hypothesis has been cited in interpretations of 14C ages from residues in the North American Plains and elsewhere. This article presents a model using an Excel spreadsheet that allows calculation of FROs with varying inputs of dead carbon and aquatic and terrestrial resources.

On the island of Lolland, southeast Denmark, an area of almost 300 ha is currently under archaeological investigation prior to the planned construction of a tunnel between Denmark and Germany under the Femern belt. The area investigated in the context of the “Femern project” includes a former fjord or lagoon, which was used both as an economic resource and as background for ritual activities in the Neolithic. The wetland conditions give excellent preservation conditions for organic material. A yet unsolved issue, however, is the question of reservoir effects. The local reservoir effect needs to be known for accurate radiocarbon (14C) dating of samples with possible aquatic carbon sources, such as human bones or food residues on pottery. Therefore, this paper attempts to calculate the local reservoir effect for the study area. I will discuss the possibilities and limitations when analyzing 14C dates from a rescue excavation. When applying the estimated reservoir corrections to a hoard of jaws and other bones, an interesting change in ritual activity at ca. 4000 cal BC can be observed. Furthermore, I examined 14C dates on bulk organic sediment and will discuss their implications for building chronologies and for reconstructing the environment of the Stone Age fjord. Finally, I will discuss the pitfalls and uncertainties associated with 14C dates for sea level reconstruction.

We consider the suitability of commonly used Poisson counting statistics applied to background count rates measured in the new generation of low-background Packard liquid scintillation spectrometers. We also investigate the stability of these systems over long time intervals. Undetected instability will result in an underestimation of the precision of any result (i.e., the calculated error will be too small), and, in the presence of a systematic source, could lead to inaccurate results. The work described here forms only a small part of a project to investigate the statistical criteria that should be applied to the performance of such counters. The procedures to be discussed here include the Poisson index of dispersion, x and s control charts and the MSSD test for detection of drift. These are illustrated on background count rates derived from the Packard 2260XL and 2000CA/LL.

The problem of a hiatus at about 6100–5300 BP (about 4900–4200 cal BC) in the prehistoric chronology of the Cis-Baikal region in Siberia is discussed. Based on a critical evaluation of existing evidence, there was no discontinuity found in the cultural sequence between the Kitoi and Serovo/Glazkovo complexes of the Neolithic, and the proposed “hiatus” may be an artifact based on underestimation of solid data. Conventional 14C dates are presented that were generated in the 1980s to early 2000s for Cis-Baikal prehistoric burial grounds, and were later dated by the accelerator mass spectrometry (AMS).

Soil samples from an 85-cm-long continuous section (PY608ES) were collected from an island in Lake Pumoyum Co (southeastern Tibetan Plateau, ∼5020 m asl) in August 2006. To estimate past environmental conditions of Lake Pumoyum Co during the Holocene, we analyzed radiocarbon ages, stable carbon isotope compositions, and total organic carbon/total nitrogen (TOC/TN) atomic ratios of the soil samples. The 14C measurements were performed with the Tandetron accelerator mass spectrometry system at the Center for Chronological Research, Nagoya University. The 14C concentration in the surface layer (101 pMC; 5–10 cm soil depth) was nearly modern. A 14C chronology of the sequence indicated that continuous soil development began on the island in Lake Pumoyum Co at ∼5800 cal BP (at 63 cm soil depth, the top of a gravel layer). These results may reflect a decrease in the lake level in the middle Holocene. The age of the obvious lithologic boundary (∼5800 cal BP) corresponds to the end of Holocene climate optimum.

The paleoclimatic signal of Lake Hovsgol in Mongolia was investigated using authigenic beryllium isotopes from 20 sediment samples. The beryllium isotopic records from this study indicate that there were three dry and cold periods at the lake around 9400, 12,700, and 17,100 cal yr BP. The significant 10Be signal during the Younger Dryas (YD) period is found to be lower. This indicates that the Lake Hovsgol area was subject to a period of cold and dry conditions with minimal dust input, which manifests itself as a low 9Be profile in this study. In warmer and wetter climatic conditions, the 10Be concentration was found to be higher, and this agrees with the sedimentation record of this study. The climatic signals from Lake Hovsgol appear to be similar to a decreased beryllium record during the deglacial period. The results of this study confirm that the Lake Hovsgol area also experienced the global paleoclimatic change associated with the YD event around 12,700 cal yr BP. Further investigation using worldwide lake records by the analytical technique of authigenic beryllium will be useful for understanding the global paleoclimatic change pattern in conjunction with lake-level change.

Two sediment cores collected from the saline lagoon St. Michiel on Curaçao (Dutch Antilles) preserve a ~5000-yr record of environmental change. Investigation of radiocarbon-dated sections by accelerator mass spectrometry (AMS) is based on faunal assemblage analyses, sediment mineralogy, and the interpretation of sedimentary facies. The cores recovered from different parts of the lagoon demonstrate different development. Initially, in the proximal part of the lagoon (core STM-2), the sediment accumulated in a coastal, semi-protected bay with strong marine influence, whereas the distal part (STM-1) was dominated by chemical precipitation (gypsum, aragonite). By about 3500–3400 BP, connection with the open sea became very limited due to the gradual formation of a coral rubble barrier at the coastline. Subsequently, the record reveals undisturbed sedimentation in the highly restricted shallow lagoon. Around 1100–1000 BP, biological and sedimentological records indicate a change to less evaporitic conditions. Stages of increased salinity are intercalated with intervals of episodic freshening due to increased runoff and precipitation. The authors demonstrate that since permanent human settlements were established on the island about 1100 BP, the watershed has undergone intensive deforestation, especially during the European colonization at the beginning of the 16th century. Deforestation resulting from agriculture and construction caused increased erosion, which was translated to increased sediment accumulation rates and a shift in lagoon sedimentation from almost entirely endogenic to mostly detrital.

There are many kinds of natural ice found on our planet. These include glacier ice, ice sheets, cave ice, massive ground ice, ice-wedge ice and permafrost ice. The problems associated with the recovery and dating of the CO2 and other gases contained in these kinds of ice is reviewed. New data are presented on various kinds of natural ice. How this kind of data can be used to help determine the origin and history of natural ice samples is discussed, along with the kind of paleoclimatic information that might be obtained from natural ice samples.

Problems of the statistical interpretation of radiocarbon age measurements of old samples are discussed, based on the notion of fiducial probability distribution. A probability density function of age has been given. A detailed discussion of different facets of the probability distribution of age has led us to the confirmation of the use of 2σ as the best limiting value between the regions of finite and infinite dates. It has been proposed to make use of the principle of constant probability P = 0.68 in the regions of both finite and infinite ages instead of the criterion N + kσ.

We had the opportunity to collect valuable wooden core samples from historic monasteries, temples, and secular buildings in 4 regions of High Asia, namely Dolpo (Nepal), ancient Nyangpo, Gyalrong/Minyag, and Lhasa and surroundings (all on the Tibetan Plateau, China). Tree species collected for dating include Pinus wallichiana (Dolpo), Juniperus tibetica, Pinus densata and several species of the genera Picea (spruce), Larix (larch), and Abies (fir) on the Tibetan Plateau, which could not always be determined to the species level due to the parallel occurrence of species of the same genus in these regions. Some of the wood samples were successfully dendro-dated with local tree-ring chronologies, but many could not, indicating a potentially higher age than the existing local chronologies. By accelerator mass spectrometry (AMS) dating and wiggle-matching 199 14C samples from 73 collected timbers, it was possible to date these wood samples with high precision, and important information about the possible time of construction of these important historic buildings was obtained for the first time. Floating chronologies of 14C-dated wood span the periods AD 650 to 900 in Dolpo and ∼200 BC to AD 420 on the Tibetan Plateau. Besides dating of the wood samples from these historic monuments, 14C AMS dating with wiggle-matching gives the opportunity to extend the range of the currently existing regional tree-ring chronologies for future environmental reconstructions on the Tibetan Plateau and the Himalayas.

An important recent development in the field of geomorphology has been the application of in-situ cosmic-ray-produced nuclides to obtain model erosion rates and surface exposure ages. These concepts emerged some four decades ago in studies of cosmogenic nuclides in meteorites, but cannot generally be used analogously for terrestrial rocks. The differences in the two cases are outlined. For the case of steady-state erosional histories, the terrestrial surface exposure ages depend on the half-life of the radionuclide studied. A suggestion is made for presenting the surface exposure ages, which allows a clear definition of the meaning of the estimated exposure ages. In the case of a discrete exposure history, the meaning of “exposure age”—which should more appropriately be called “event age”—is however quite unambiguous.

Very incautiously, after printing 25 volumes of Radiocarbon, the editors have authorized some personal reminiscence. Like all “Quaternary scientists”—no better collective name is available for our strange profession—I have been engaged in historiography, writing about history, for many years. In 1946, when natural radiocarbon was discovered, my subject, the sedimentary history of lakes, was only one of several kinds of historical record that needed, and soon received, a new reading. At the time, not all custodians of other kinds of record were ready to agree that new readings were conceivable, let alone necessary. The record of their persuasion—some of which has been written by Greg Marlowe (1980) in “W F Libby and the Archaeologists”—is part of the history of historiography. To the bibliography of this dangerously abstract subject I venture to add some minor footnotes. They come, not from historical research like Marlowe's, but from a leaky, selective memory.

The Abrolhos bank, in southern Bahia State (BA), is the largest coral reef system in the southwestern Atlantic. It is highly influenced by the Brazil Current (BC), since it is located in the continental shelf. By contrast, Todos os Santos Bay (TSB), in Salvador, capital of Bahia State (BA) has an important coral biodiversity, located in a bay inlet with restricted water circulation. Coral cores were collected in those sites and were analyzed for density band counting and by Th/U dating to estimate growth rates and age. In this work, we present 14C ages of some of these bands in order to evaluate the marine reservoir effect (MRE) to which the colonies were subjected during growth. It is the first study making use of coral skeleton samples for MRE determination for the Brazilian coast. ΔR was calculated to be –151±23 14C yr, while that for the TSB was –107±51 14C yr.

There is a growing database of radiocarbon (14C) reconstructions from biogenic carbonate taken from marine sediment cores being used to investigate changing ocean circulation and carbon cycling at the end of the last great ice age. Reported here are 14C results from a marine core taken in the Makassar Straits of the western equatorial Pacific that was intended to test whether there was evidence of geologic carbon release to the ocean during the glacial termination. A thorough investigation of planktic and benthic 14C ages with stable isotopes and CT-scans revealed extensive burrowing in the upper 2 m of the core that displaced younger sediments downward by more than half a meter into the glacial section of the core. The vertical displacement is evident in both planktic and benthic fossils. However, the extent of displacement and the stratigraphic disturbance became evident only after multiple measurements of different species and genera. A CT-scan prior to sampling would be an effective screening tool to avoid sampling problem cores such as this.

The following list consists of dates of archaeologic and geologic samples measured from January 1981 to December 1982. Measurements were continued with the same proportional counter system, pretreatment procedure, methane preparation, measurement, and calculation, as described previously (Kanwiszer & Trzeciak, 1984). Ages were computed on the 14C half-life of 5568 ± 30 years. Precision is reported as one standard deviation based only on statistical counting uncertainties in the measurement of the background, NBS modern standard, and sample activities. The dates are not corrected for 13C fractionation. Descriptions and comments are based on information supplied by submitters of samples.

We establish a high-precision radiocarbon chronology for 2 house depressions at CA-SCRI-333, a large prehistoric village on the western end of Santa Cruz Island, California, USA. SCRI-333 is a large mound composed of a shell midden with more than 50 house depressions evident across its surface. We develop a chronology of occupation and activity for 2 of these depressions (6 and 32) based on a stratified sequence of accelerator mass spectrometry 14C dates. Carbonized twig and marine shell (Mytilus californianus) samples were selected from well-defined stratigraphic sections. Analytical error for these measurements is ±20 14C yr. We use a Bayesian statistical framework to propose an age model for the deposition of 2 features that may be associated with house construction. These data indicated that the features were not contemporaneous and suggest that house construction may have been sequential during the site's occupation, a hypothesis that needs to be tested further. The methodologies used in this study have the potential to increase the chronological precision of household archaeology at SCRI-333, on the northern Channel Islands, and around the world.