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).

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.

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.

After introducing the liquid scintillation counting (LSC) method and graphite target preparation for accelerator mass spectrometry (AMS) measurements in the Zagreb Radiocarbon Laboratory, the existing database software designed only for gas proportional counting (GPC) (using a DOS operating system) could not satisfy the requirements for parallel conduction of several techniques. This has been enabled recently by the development of the new relational database ZAGRADA, which—using SQL scripts and constraints defined by primary and foreign keys—enforces high data integrity and provides better performances in data filtering and sorting. The structural scheme of this database conceptually comprises 4 basic modules with data on the samples, chemical pretreatment and preparation, measurements and data on the final results. A user-friendly graphical user interface has been designed to perform various actions and data manipulation to the database. The implementation of a new database for 14C samples has significant contribution to scientific research performed in the Radiocarbon and Tritium Laboratory and to quality assurance and quality control, and will enable better and easier communication with customers.

Fewer than 200 radiocarbon (14C) dates with secure contextual information are available for Cuba, making it challenging to reconstruct Caribbean indigenous population dynamics, their identities and interactions. In this paper, we discussed 21 accelerator mass spectrometry (AMS) 14C dates from two mounds (M1 and M2) at the Playa del Mango site (Granma province, Cuba), traditionally associated with the Banwaroid stone tool tradition. The ΔR calculated for the site was –132.0 ± 176 and –164.0 ± 68. The chronology of burials from the peripheral area of M2 suggested that the cemetery was continuously used from at least cal BC 116–AD 241 (2 σ). The domestic area of M2 was used at minimum between cal BC 55–AD 435 (2 σ), which encompasses the use of the funerary areas. An isolated human tooth from M1 [cal AD 125–435 (2 σ)] suggested that this funerary area is later than the one at the periphery of M2, and possibly contemporaneous with the later formation of the M2 shell midden. The archaeological assemblage of the “Banwaroid tradition” is widely distributed in Cuba, and mixed with other archaeological traditions, supporting that a complex web of human interactions took place in the Caribbean in precolonial times.

When European colonists arrived in the late 19th century, large villages dotted the coastline of the Gulf of Papua (southern Papua New Guinea). These central places sustained long-distance exchange and decade-spanning ceremonial cycles. Besides ethnohistoric records, little is known of the villages’ antiquity, spatiality, or development. Here we combine oral traditional and 14C chronological evidence to investigate the spatial history of two ancestral village sites in Orokolo Bay: Popo and Mirimua Mapoe. A Bayesian model composed of 35 14C assays from seven excavations, alongside the oral traditional accounts, demonstrates that people lived at Popo from 765–575 cal BP until 220–40 cal BP, at which time they moved southwards to Mirimua Mapoe. The village of Popo spanned ca. 34 ha and was composed of various estates, each occupied by a different tribe. Through time, the inhabitants of Popo transformed (e.g., expanded, contracted, and shifted) the village to manage social and ceremonial priorities, long-distance exchange opportunities and changing marine environments. Ours is a crucial case study of how oral traditional ways of understanding the past interrelate with the information generated by Bayesian 14C analyses. We conclude by reflecting on the limitations, strengths, and uncertainties inherent to these forms of chronological knowledge.

The following list includes some measurements made during 1975-1978 since our last list (R, 1978, v 20, p 62-67) in the National Radiocarbon Laboratory of the Ecole Nationale Supérieure de Géologie Appliquée et de Prospection Minière (ENSG) de Nancy.

Measurements have continued with the same proportional counter system, the same procedure in sample pretreatment, methane preparation and measurement, and the same age calculation using a half-life of 5568 ± 30 yr as described previously (R., 1970, v. 12, p. 298–318).

The C14 measurements reported here were made in this laboratory between July 1969 and September 1970. The dating system consists of a 0.55 L copper-walled proportional counter (adapted from östlund and Engstrand, 1963, constructed by Outokumpu Oy, Research Lab., Tapiola, Finland) surrounded by a lead cylinder, 1.5 cm thick, placed within an anticoincidence meson detector. The system is encased in selected lead 1.5 cm thick, 7 cm of paraffin wax with ca. 10% boric acid and ca. 20 cm iron. Counter gas is CO2 with which the counter is filled to 228.6 m Hg at a detector temperature of 20°C. Background is 1.50 cpm and net contemporary value is ca. 10.0 cmp.

Procedures and equipment of the laboratory have been described in previous date lists. Lake cores and marls are treated with acid only, wood, charcoal, and peat samples with dilute NaOH and dilute H3PO4 (unless indicated otherwise) before conversion to methane which is used as counting gas.

The Oxford 14C accelerator has operated with beam for some 400 hours. This report describes the progress made towards achieving dates from milligram samples with the required accuracy of better than 2%. In summary, it shows how 14C is relatively easily detected, but that the overall beam optical system is, at present, rather sensitive to effects which prevent reliable maintenance of the necessary isotope ratio stability. These effects can probably be eliminated by careful attention to details of the design rather than by major modifications.

Archaeologists tend to use typochronological frameworks to date their sites. These are based on the appearance of certain cultural markers such as grave types or houseplans. In the Meuse-Demer-Scheldt region, a chronological framework is used for the cremation cemeteries from the Middle Bronze Age until the Late Iron Age based on the size, number, and presence of different types of cremation graves. Radiocarbon dating of cremated bone from the small cemetery at Lummen-Meldert dates this site to the Late Bronze Age. These results challenge the hypothesis that small cremation cemeteries with mostly “unurned” graves date to the Middle Iron Age. The cremation graves without an urn and grave goods are a specific category that has to be dated by absolute dating methods such as 14C. The results also suggest a connection with the funerary traditions in the Atlantic region.

A bibliography of the radiocarbon dating literature for the years 1948-68, which is in the process of compilation, is examined and a format is proposed. A survey of literature growth has also been undertaken. This enables projections of the numbers of publications referring to radiocarbon dating to be made. The estimated number of publications for the year 1978 is compared to literature retrieval obtained by interrogating eight relevant computer data bases. It is concluded that computer information retrieval is not satisfactory. Bibliographic control of radiocarbon dating literature would be best achieved by a bibliography dedicated to the subject and updated at regular intervals.

I have made an evaluation of 0.3-ml minivials for 14C dating of small samples by liquid scintillation counting of benzene. A calibrated wood standard was diluted by varying amounts of ancient CO2, with synthesized benzene counted in both conventional 3.0-ml vials and 0.3-ml minivials in a 1220 Quantulus. The accuracy and precision of results are compared for samples ranging in weight from 50 to 240 mg of carbon. I examined two significant potential problems associated with handling small samples, namely, memory effects within the vacuum system, and signal within the dilution gas. Although accurate radiocarbon dates can be obtained using either standard vials or minivials, minivials are more suitable for dating small samples because they are less influenced by these sources of error.

Lime burials are a characteristic phenomenon of the protohistoric funerary tradition on the Balearic Islands. At Cova de Na Dent, a lime burial has been sampled for analysis. The lime burial was made up of lime and fragmented bones. Six layers were sampled and described in the laboratory according to their color, the consistency of the deposition, and the aspect and quantity of the bone fragments. Bone samples and lime were dated. The lime was analyzed by using petrographic analysis, X-ray diffraction, FTIR spectroscopy, and simultaneous thermal analysis. The results show that the bones were cremated in the presence of crushed rock carbonate. The 14C dates on the lime suggest an earlier chronology for this ritual, starting in the Bronze Age, as generally is accepted.

We studied the structure and development of the Holocene floodplain of the Labe (Elbe) River by radiocarbon dating sections of the upper and middle courses of the river. We focused on geomorphological and sedimentological conditions, mineralogy and the chemical composition of sediments. We established the stratigraphy of the Holocene deposits of the floodplain. The results of our investigation of fluvial sediments imply that several abrupt changes in temperature and precipitation occurred during the Holocene. These changes led to intervals of hydrological disequilibrium, which caused the formation of two Holocene terraces and a contemporaneous floodplain. The lower terrace was flooded and covered with sediments upon which the recent floodplain formed. During the Holocene, there were four periods during which large tree trunks were deposited in the fluvial sediments, indicating periods of extensive flooding. The supposition that these events were of more global scale is supported by the results of investigations made on the Holocene floodplains of other regions.

The chronology of human presence in Chontales, central Nicaragua, was established by Franck Gorin (1989), who applied a combination of absolute dates and ceramic associations to build a sequence comprised of six different phases. However, interpretative and chronological issues have arisen due to two main problems. First, the sequence was based on stylistic associations to polychrome ceramics from Pacific Nicaragua. Second, the sample analyzed by Gorin shows contextual bias and lacks sufficient absolute dates. As a result, a comprehensive regional research plan was established to test the current accepted chronology, and redefine it where necessary. In this paper, we present the first date list for the Valley of Juigalpa, Mayales River subbasin (Chontales, Nicaragua). Contrary to Gorin’s proposal, which established a chronology from 500 BC through AD 1600, reports on new seventeen radiocarbon (14C) assays show a cultural sequence from 1420 ± 30 BP, or cal AD 595–660 (±2σ) through the present.

This paper addresses the absolute chronology of the earlier Yunatsite and Ezero cultures in Upper Thrace (South Bulgaria), from Early Bronze I and the beginning of Early Bronze II. The two newly obtained radiocarbon dates from Early Bronze Dubene-Sarovka (the Upper Stryama Valley) are published and discussed in a detailed stratigraphic and comparative Early Bronze I–Early Bronze II context. Date Bln-5233 (3490–3120 cal BC) is the first 14C date from the Upper Maritsa valley from Early Bronze I with well-defined stratigraphic context and values earlier than 3100 BC. This date adds new arguments to the discussion of the 14C dates from Yunatsite 15 and Plovdiv–Nebet Tepe, and addresses the question of the comparative chronology of Yunatsite I and Ezero I cultures from the late fourth millennium BC.

The sample of the date Bln-5231 (2870–2620 cal BC) comes from a level on the border between Early Bronze I and Early Bronze II. On one hand, its values preceded the values of the earlier-obtained 14C dates from IIB layer and confirmed the stratigraphic sequence at Dubene-Sarovka tell. On the other hand, the calibrated values seem to be later than the vast comparative chronology of the end of the Dubene IIA&Mdash;the beginning of Dubene IIB (ca. 3000 BC). Similar problems occur with dates from Yunatsite and Ezero. The published new dates from Dubene-Sarovka are part of the project on complex elaborating of the Early Bronze absolute chronology in the Balkans, and especially on contextual analysis of the 14C dates.