Plans for a radiocarbon dating laboratory at the University of Lund were initiated by Tage Nilsson and Holger Arbman in 1962. Work was begun in 1964 and at the end of 1965 most of the dating equipment was installed. Dating began in 1966 after careful testing of counting electronics and counters.

The dating system has two 1-L copper-walled proportional counters of Östlund-Engstrand construction (for details see Stockholm V. p. 204, Fig. 1) surrounded by 2.5 cm of selected lead, followed by a ring of 23 cosmic-ray Geiger counters (model HZ-100, Zentralwerkstatt Göttingen). On all sides are at least 20 cm of iron. Above and on both long sides of the counters are 10 cm of paraffin wax with about 12% boric acid between the iron layers.

The British Nuclear Fuels plc reprocessing plant at Sellafield in Cumbria, Northwest England, discharges between 1 and 3 TBq of 14C per annum as low-level waste via a pipeline into the Eastern Irish Sea. Our results demonstrate 14C activities in excess of the current ambient level (i.e., ca. 260 Bq kg−1 carbon) in a range of both biotic and abiotic samples with evidence that a significant percentage of the discharges are in the form of dissolved inorganic carbon (DIC). There also appears to be a significant seasonal influence on the uptake of the DIC by the phytoplankton, most likely linked to their bloom periods. Results from different aspects of the research are integrated to provide an opportunity to consider the overall distribution and behavior of 14C in the Eastern Irish Sea. We also discuss the results in terms of existing sediment chronologies and sedimentation rates and consider the possible consequences of phytoplankton blooms on the cycling of the other radionuclides.

Through the establishment of radiocarbon chronozones relating common geological events within lacustrine and eolian sediments from five profiles representative of loess yuan (tablelands), river valley and northwest margin features of the Loess Plateau, we propose a series of stratigraphic divisions within the last 30 ka. The focus of this detailed study involves stratigraphic relationships contributing to evidence of Younger Dryas events, with the recognition of cold-dry, cool-wet and cold-dry periods represented within the Heiheze silt, Midiwan peat and Liushuwan eolian sand. The stratigraphic profiles reflect century-scale fluctuations of the East Asian monsoons. The precursor events enable us to place the Pleistocene/Holocene boundary at 10,000 bp.

A geochronological survey of the Bengal shelf area involved results from more than 20 sediment cores dated using gamma spectrometry and the nuclides 137Cs, 228Ra, 226Ra, and 210Pb. In some cores, which contained older sediments, 32Si and 14C were determined to examine the possibility to extrapolate the obtained chronologies to century and millennial scale. Geochronological work in this region is faced with problems of cyclone-induced sediment reworking, grain-size effects on fallout nuclides, scarcity of carbonates, unknown 14C reservoir effect and sedimentation rates that are too high to obtain sediment cores long enough to establish a chronology. Despite these problems, comparison between the results of the different dating methods provided the most reliable sediment balance to date for the submarine delta of the Ganges-Brahmaputra river system and indicated that on a time scale of several centuries at least 35% of the annual sediment load is deposited.

Since the 11th International Radiocarbon Conference considerable advances have been made in European dendrochronology giving several long continuous absolute chronologies. Recent collaboration between European laboratories provides confirmation of the accuracy of these chronologies and, thus, of the standards used for radiocarbon calibration.

Radiocarbon (14C) concentrations in the oceans are different from those in the atmosphere. Understanding these ocean-atmospheric 14C differences is important both to estimate the calendar ages of samples which obtained their 14C in the marine environment, and to investigate the carbon cycle. The Marine20 radiocarbon age calibration curve is created to address these dual aims by providing a global-scale surface ocean record of radiocarbon from 55,000–0 cal yr BP that accounts for the smoothed response of the ocean to variations in atmospheric 14C production rates and factors out the effect of known changes in global-scale palaeoclimatic variables. The curve also serves as a baseline to study regional oceanic 14C variation. Marine20 offers substantial improvements over the previous Marine13 curve. In response to community questions, we provide a short intuitive guide, intended for the lay-reader, on the construction and use of the Marine20 calibration curve. We describe the choices behind the making of Marine20, as well as the similarities and differences compared with the earlier Marine calibration curves. We also describe how to use the Marine20 curve for calibration and how to estimate ΔR—the localized variation in the oceanic 14C levels due to regional factors which are not incorporated in the global-scale Marine20 curve. To aid understanding, illustrative worked examples are provided.

An overview will be presented of stable isotope data (δ13C and δ15N) available from animal and human bones from Roman to post-Medieval Belgian sites. The data will be used to assess trends in the human diet and evaluate the possible impact of reservoir effects originating from the consumption of fish derived from marine or freshwater environments. Historical and archaeozoological data demonstrate drastic changes in fish consumption throughout the last 2 millennia and thus suggest that fluctuations through time of the impact of the reservoir effects can be expected. However, the present stable isotope data set does not support this suggestion.

Sambaquis, famous Brazilian coastal shellmounds, represent a successful and long archaeological cultural tradition, with hundreds of sites spread over 2000 km of the Brazilian south-southeast coastline. These sites have many burials within a sequence of layers comprising a mix of faunal remains, charcoal, ashes, and sand, thus resulting in very complex stratigraphic structures. Several radiocarbon samples exhibit ages between 8000 and 1000 cal yr BP. In the Brazilian southeastern coastal hinterland, at the Ribeira de Iguape basin, 36 small mounds similar to the sambaquis were found, composed mostly of landsnail shells, bone remains of terrestrial fauna, lithic and osteodontological artifacts, and quite a few burials. Through the last decade an archaeological research project has accomplished extensive surveys and systematic 14C sampling, together with excavations in selected sites. A sequence of ages has been obtained from different samples (16 on shell, 10 on human bone, and 6 on charcoal) representing 19 sites. These dates range from 10,000 to 1000 cal yr BP, highlighting around 9000 yr of cultural continuity, contemporary to both the Paleoindian record over the hinterland plateau, and older than their coastal counterparts, the sambaquis. By presenting the 14C distribution and an overview of the archaeological features of these sites, we discuss briefly the dispersion and settlement processes of early peopling in this area of Brazil.

Natural C14 measurements have been performed at Gakushuin University since 1959, using a proportional counter of 400 ml (Kigoshi and Tomikura, 1960). The counter presently in service is made of copper tubing and has an effective volume of 900 ml. Acetylene gas is used as counting gas at pressure 600–760 mmHg and prepared in the same way as in the case of 400 ml counter. The counter is shielded by iron sheets of 23-cm thickness and by anti-coincidence with a multianode propane-flow proportional counter of Houterman's type (Houtermans, 1958). A background of 5.6 counts/min has been attained with this counter arrangement. The modern carbon sample filled at 0°C and 760 mmHg shows an activity of 11.8 counts/min. The samples with code numbers greater than GaK-60 were measured by this counter.

14C in high-altitude rocks and in Antarctic meteorites of long terrestrial age has been found at levels consistent with in-situ production by cosmic rays. Levels of 0.2–0.59 dpm/kg (or 1.0–2.6 × 10614C/g) are found in high-altitude samples ranging from 3300 to 5460m. Similar values are observed in Antarctic meteorites that have been dated by 81Kr by Freundel, Schultz & Reedy (1986) as over 100 kyr old.

From the early days of radiocarbon dating, the standard sample treatment has involved removal of contamination from carbonates and humic acids by washes in acid and base, respectively. A modification of this acid-base-acid (ABA) method has been suggested, especially for material older than 20,000 yr. However, the criticism of ABA and application of a more aggressive oxidizing method, such as wet oxidation (ABOX) or cellulose extraction, might only be needed in some special cases, for example, in the case of poorly preserved or chemically treated wood. Separation of cellulose seems to be the ultimate solution; however, it is not always applicable when samples contain small amounts of wood. As a part of studies focusing on the chronology of late Pleistocene sedimentary processes in the Venetian–Friulian Plain and Carnic Alps (NE Italy), 14C analyses were performed on old wood samples found in sedimentary deposits of pre-Last Glacial Maximum (LGM) age. Wood samples were treated by five methods: ABA, two modified ABA treatments (ABOX and ABA+Bleach), as well as two different cellulose separations. Infrared spectra of treated samples and 14C results show that in most cases the ABA method is sufficient in removing the contamination of naturally deposited wood, even when the wood is of very old age.

Lime lumps and bulk mortars show different 14C contamination when analyzed in several CO2 fractions isolated from the effervescence of an ongoing hydrolysis reaction. Age profiles of both materials are therefore highly complementary and together they can provide a reliable date. Furthermore, they can also reveal the complexity of the radiocarbon (14C) distribution within the mortar and thus prevent over-interpretation of the data. The lime lump versus bulk mortar dating data presented here has been collected over 22 years, with only a small fraction of the results so far published internationally. Since there has been an increasing interest in mortar dating over recent years with a special focus on lime lumps, and since many laboratories have just begun mortar dating experiments, we wish to present some of the extensive data that already exist. Previously published data from 15 lime lumps (including 34 14C measurements from sequential dissolution) and 43 new 14C measurements from 17 lime lumps are presented here. The samples are from medieval Finland and Sweden, classical Rome and medieval Italy, and the Roman Jerash (Gerasa), Jordan.

Our stratified radiocarbon dates from EB Jericho (Trench III) on short-lived material are significantly older than conventional archaeo-historical time frameworks. The calibrated 14C date of Stage XV Phase li-lii (Early to Middle EB-I Kenyon) is 100–450 years older. Stage XVI Phase lxi-lxii (Early EB-II Kenyon) is 200–500 years older. Stage XVI Phase lxii-lxiii (destructive end EB-II) is 200–300 years older. Stage XVII Phase lxviii a – lxix a (Early EB-III) is 100–300 years older than conventional archaeo-historical time estimates. As the beginning of the Chalcolithic in the Near East has “become” a 1000 years older, from about 4000 in the 1960s to about 5000 BC in current perception based on 14C dating, it should not be surprising that the Early Bronze Age and related Egyptian Dynasties also yield 14C dates that are older by a few hundred years than current archaeo-historical time frameworks. Egyptian chronology should not be regarded as ultimately fixed. Egyptologists in the first half of the 20th century gave much older dates for the earlier Dynasties. The new 14C evidence is overwhelmingly in favor of an older Early Bronze Age and older dates for Dynasties 1–6.

The 14C content in 1961–1967 and 1970–1983 tree rings of a spruce grown in Dailing, China (47°N, 129°E) was measured by liquid scintillation. As a result of USSR bomb tests at Novaya Zemlya (72°N, 53°E), Δ14C values rose dramatically from 250‰ in 1961 to a maximum 909‰ in 1964, and then gradually decreased to 238‰ in 1983. We compared Δ14C values in the rings of an oak tree grown at 43°N, 74°W and that of a pine grown at 49°N, 9°E, and atmospheric Δ14C values in both northern and southern hemispheres. We observe that: 1) annual tree rings grown in the same latitude zone have the same Δ14C values, reflecting rapid longitudinal mixing of the atmosphere; 2) atmospheric 14C concentrations reached a global equilibrium distribution at the end of 1968, and tree ring 14C content reflects atmospheric 14C concentration; 3) 1976–1982 rings of the Dailing spruce show excessive 14C, likely due to the effect of 1976 and 1980 Chinese bomb tests; 4) Δ14C decreases exponentially, halving every 17 yr.

High-precision 14C measurements are presented, carried out on single tree rings from a section of the floating South German Neolithic tree-ring chronology. They confirm the existence of pronounced medium-term variations in the order of 2 percent during the 33rd to 38th centuries BC.

These variations turn out to be very regular while the precision of 1.5‰ allows a comparison with a geochemical model calculation. Good agreement is acquired for an input function with a periodicity of about 150 years and an amplitude of approximately 30 percent in the 14C production rate.

A series of shell samples has been studied to determine the magnitude and mechanisms of carbon exchange between shells and their environment. Laboratory contamination experiments included the storing of shell samples in acid and calcareous environments of different 14C concentrations as well as studies of carbon exchange in the course of thermal recrystallization in solid state in an atomosphere of carbon dioxide. The applicability of differential thermal analysis to studies of the structure and texture of shells is discussed.

The radiocarbon of the local reservoir effect (RE) was observed in many sectors along the Argentinean Patagonic coast. Results show variations in the 14C offsets and differences between marine and continental species growing within the same locality, ranging from about 80–1100 yr BP. It is postulated that such variations are mainly due to local factors, including the coast morphology and the contribution of continental waters. The relevance of these kinds of studies for the interpretation of age in archaeological samples is highlighted in this paper.

In early 1982 we attempted to compile information on 14C counting equipment from all laboratories listed in RADIOCARBON. A gratifying number of laboratories cooperated in communicating their data: more than 65% of those in which proportional counters are in operation. Our compilation covers more than 80% of all gas counters used for 14C dating. Unfortunately, the number of parameters determining counter quality as well as the spread in these factors is so large that their separate influence cannot be established beyond statistical doubt. Nevertheless qualitative and semi-quantitative trends are clearly observed. Laboratories are not identified in the data but the calculations and standardization procedures allow the laboratories to identify their own counter data in the graphs. Each plot does not contain a complete compilation of all counters. This is either because of lack of or internally inconsistent information.

14C is produced as an activation product in nuclear reactors, and may be discharged to both the atmosphere and the marine environment during nuclear fuel reprocessing. In the UK, 14C is discharged, under license, into the Eastern Irish Sea by the British Nuclear Fuels plc (BNFL) reprocessing plant at Sellafield, Cumbria, northwest England, and is then transported into Scottish coastal waters. We analyzed intertidal biota samples to determine the effect of these discharges. The specific activities of 14C found in these samples indicate that the uptake and bioaccumulation of 14C is dependent on the type of organism and its feeding behavior. Measured 14C concentrations in mussels (Mytilus edulis) were higher than those in winkles (Littorina littorea), which were greater than those found in seaweed (Fucus spp.); maximum observed activities were ca. 7, 5 and 3.5 times the accepted current ambient level of 260 Bq kg−1 C, respectively. Annual Nori (Porphyra umbilicalis) samples were analyzed for their 137Cs, 241Am and 14C contents; both the 137Cs and 241Am results correlated well with published Sellafield discharge data (r = 0.877 and 0.918, respectively), whereas there was no significant correlation between measured 14C activities and the discharge record, indicating increased complexity in the chemical and biological behavior of 14C or some discrepancy in the estimated discharge records.

Ever since José de Acosta's prescient speculation, in 1590, that Native Americans were descended from “savage hunters” who had followed game animals across a land bridge from northeastern Asia into northwestern America (Acosta 1604), most serious scholars have assumed that this was the migration route. The main point of dispute has been the date when the ancestral Asians made the crossing. After many nineteenth-century claims of the discovery of stone tools or bones of “early man” failed to withstand scientific scrutiny, a conservative reaction set in, embodied by the hyper-skeptical Aleš Hrdlička of the Smithsonian Institution. Hrdlička dismissed all claims of a human presence in the Americas prior to about 5000 years ago.