It is well known that, during the widely used AAA pretreatment (de Vries and Barendsen 1954), alkali treatment is responsible for the incorporation of modern carbon due to the precipitation of atmospheric CO2 as carbonate. Until now, the last step of the experiment, consisting in acid treatment (most of the time with hydrochloric acid) was considered to be sufficient to eliminate all of lab contamination. But wood, peat and sediment present a complex molecular structure. During radiocarbon chemical treatments, functional groups still present in the molecules are likely to form ionic bonds with “modern” carbonates. These new chemical bonds resist a “classical” acid treatment and are responsible for rejuvenation. This short paper presents preliminary results for two common 14C cases: rejuvenation of a 0.4 pMC wood and of an Oxygen Isotope Stage 3 (OIS3) paleosol. For both cases, contamination due to incorporation of modern carbon during chemical treatment is evaluated and an alternative protocol is proposed.

The glyptodont (Glyptodontidae Burmeister 1879, in Ameghino 1889), a giant cousin of the armadillo, has long been thought to have disappeared in South America at least 10,000 years ago at the end of the Pleistocene. There are indications that the glyptodont had some interaction with ancient hunter-gatherers peoples (Politis et al. 1987; Politis 1995), but the precise time of its extinction has never been well established. Most recently, a brief mention of 14C dates of 7500 to 6500 BP (Geotimes 1996) for glyptodont remains discovered at La Moderna (Azul Department, Buenos Aires province, Argentina), has aroused excitement because the new younger dates have changed the traditional idea about the survival and extinction of this beast.

A number of recent radiocarbon determinations from several sites in Israel suggest advancing, by some considerable period of time, both the onset of the cultural horizon known as Early Bronze I and the appearance of its latest phases. The logical outcome of the acceptance of these new dates puts such a strain on chronological correlations between the 14C data and the archaeological record that the entire system would no longer be tenable if they were accepted. This paper examines in detail the problematic nature of these “uneasy correlations.”

Due to very high accumulation rates, loess sequences are best suited archives for the continental paleoclimate of glacial periods. Accurate chronologies cannot be easily established by radiocarbon-dating, because of the lack of organic macrorests, the only material for reliable 14C dating so far. A chemical protocol is reported to extract the organic matter of loess (organic carbon content lower than 0.1% by weight) for accelerator mass spectrometry (AMS) 14C dating. Sediments were taken from the loess sequence of Nussloch, for which a large dataset of luminescence ages (TL, IRSL/OSL) is available. The 14C chronology of the organic matter extracted from loess is in good agreement with the corresponding luminescence ages. It allows high resolution correlations with climatic proxy signals (magnetic susceptibility, malacological assemblages, δ13C on organic matter, etc.) derived from the loess sequence and global environmental proxy records.

Several single-piece shell fishhooks from CA-SRI-43 on Santa Rosa Island were dated by association to roughly 5500 cal BP and were argued to be among the oldest specimens in the region. Direct accelerator mass spectrometry (AMS) radiocarbon dating of one of these hooks provided a date of 560 cal BP, however, making it about 5000 yr younger than originally presumed. This younger date is more consistent with the regional shell fishhook chronology and demonstrates the importance of obtaining direct AMS 14C dates to refine artifact and site chronologies.

Between 1984 and 1995 over 450 organic samples were collected from monuments built during the Old and Middle Kingdoms. The most suitable samples were selected for dating. The purpose was to establish a radiocarbon chronology with samples from secure context and collected with the careful techniques required for 14C samples. This chronology is compared to the historical chronology established by reconstructing written documentation.

This study describes a sample preparation technique used to isolate dissolved organic carbon (DOC) in groundwater for radiocarbon analysis using accelerator mass spectrometry (AMS). The goal of the work is to improve our ability to determine groundwater residence times based on 14C measurements of the DOC fraction in groundwater. Water samples were collected from carbonate and volcanic rock aquifers in southern Nevada. Multiple measurements of total dissolved organic carbon (TDOC) in groundwater from one site are used to demonstrate the reproducibility of the analytical procedure. The reproducibility of the method is about one percent (1σ) for a 0.5 mg sample. The procedural blank for the same size sample contains about 1 percent modern carbon (pMC).

Stratigraphic investigations together with climatic proxy data measurements and reliable radiocarbon dating show a history of fluctuations of dry and wet environmental conditions in the arid to semi-arid zone of northern China since the late Pleistocene. Based on these data, we are able to reconstruct shifts of the desert margin in two period extremes, the last glacial maximum (21–15 ka) and the Holocene Optimum (9–5 ka). We have compared the present desert margin with that for the two extremes. The results indicate that a southward shift of the present margin of about 3 degrees in latitude might be caused by anthropogenic impact. Hence the influence of human activity must be taken into consideration for sustainable development and environment protection. Future research will be to find a two-way feedback existing between climate and anthropogenic impacts.

Smoothed curves are least-squares fitted to three sets of decadal radiocarbon calibration data from New Zealand and British Isles (AD 1725–1935) and western North America (AD 1145–1945). The curves are compared with each other and with a curve previously calculated from New Zealand data (AD 1335–1745). The smoothing procedure results in reduced standard deviations of the curves, but at the expense of time resolution. The comparison shows a variable 14C offset between the northern and southern hemispheres of 0–70 years (Southern Hemisphere older), and a Northern Hemisphere longitudinal variation of −20 to +60 years (British Isles generally older than western North America).

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.

We have developed and demonstrated a practical methodology for dating specific compounds (and octade-canoic or stearic acid—C18:0—in particular) from the lipid material surviving in archaeological cooking pots. Such compounds may be extracted from about 10 g of cooking potsherd, and, after derivatization, can be purified by gas chromatography. To obtain sufficient material for precise dating repetitive, accumulating, GC separation is necessary. Throughout the 6000-year period studied, and over a variety of site environments within England, dates on C18:0 show no apparent systematic error, but do have a greater variability than can be explained by the errors due to the separation chemistry and measurement process alone. This variability is as yet unexplained. Dates on C16:0 show greater variability and a systematic error of approximately 100-150 years too young, and it is possible that this is due to contamination from the burial environment. Further work should clarify this.

Chrono-sequences of paleosols buried under different mounds of the large Ipatovo Kurgan, constructed during the Bronze Age, have been studied to reconstruct climatic changes in the dry steppe zone of the Northern Caucasus, Russia. Abrupt climatic and environmental changes in the third millennium BC have been reconstructed, using morphological and analytical data of the soil. Based on accelerator mass spectrometry (AMS) dates of small charcoal fragments from the soil chrono-sequence, we concluded that two upper paleosols (with the clearest evidence of arid pedogenesis) developed between about 2600–2450 BC.

This research stems from an earlier study of the lichen covering with oxalate deposits at the Arc de Berà monument. The initial objective of dating these biodeposits opened up other questions concerning the structure of these deposits and how they were formed. Some dating results gave an absolute age greater than the monument itself, which posed various hypotheses on the possible ageing mechanisms.

Reliable radiocarbon dating depends upon well-defined samples. We have been investigating whether or not reliable 14C dates can be obtained directly from sub-fossil insect cuticle or biochemical fractions derived from it. Initial carbon and nitrogen stable isotope measurements on sub-fossil insect chitin from species with known feeding behaviors found within a single site (St Bees, Cumbria) clustered in a manner reminiscent of trophic level effects seen in terrestrial ecosystems. Although this finding implied some chemical stability, the measurement of CN ratios from the same samples indicated compositional variability. In addition, 14C dates obtained from these same samples were different from dates obtained from plant macrofossils found at the same depth. We have experimented with protocols designed to biochemically reduce chitin to its principle carbohydrate component glucosamine with the aim of using this compound to generate reliable 14C dates. Solvent extractions of sub-fossil chitin were carried out to remove both endogenous and exogenous lipid-soluble materials. Base hydrolysis reactions designed to extract polypeptides retained surprisingly high levels of contaminating amino acids. Proteinase K enzyme treatment had little affect on the level of amino acid contamination. Strong acid hydrolysis reactions designed to depolymerize chitin to glucosamine yielded only 5% glucosamine. Clearly alternative methods of chitin depolymerization must be identified before the purification and 14C dating of glucosamine from sub-fossil chitin becomes practical.

The purpose of a reservoir offset is to enable the application of calibration data (μ(θ), e.g. Stuiver et al. 1998) developed for one reservoir (primary reservoir) to CRAs from another (secondary reservoir), for example the use of a hemispheric offset for terrestrial samples (Barbetti et al. 1995; McCormac et al. 1998; Sparks et al. 1995; Vogel et al. 1986, 1993). The usual approach has been to define the activity of the secondary reservoir as some form of constant offset (with error) from the primary reservoir (e.g. Higham and Hogg 1985; McFadgen and Manning 1990). In this case, all CRAs from a secondary reservoir are given the same offset. The value of this common offset is not known exactly, but any uncertainty in the measured value of the offset corresponds to uncertainty in the common offset for all CRAs. However, the standard procedure for incorporating offset error into CRAs incorrectly allows a different offset for each CRA. The offset for each CRA is incorrectly allowed to vary by the measurement error reported for the offset value. Technically, the offset is incorrectly treated as varying independently from one CRA to the next, when in fact it is a single parameter for the secondary reservoir in question. In light of this, the calibrated date distributions will be incorrect for CRAs where an offset has been applied and the standard approach to offset error treatment has been used. In many cases, the differences between correct and incorrect calibrated date distributions will be insignificant. However, in some cases significant differences may arise and other approaches to treating the error associated with offsets need to be adopted.

We discuss the significance of 32 radiocarbon dates from the archaeological sites of Tel Beth Shean and Tel Rehov in northern Israel. All dates are from Iron Age I and II archaeological contexts (12th–8th centuries BCE). Most of the dates were done on short-lived samples (seeds and olive pits), while some are on charred timber. The samples are organized in several homogeneous clusters according to their context. This series is one of the largest groups of 14C dates from the Iron Age in the Levant. The paper discusses the correlation between the 14C dates and the traditional archaeological dates of the same context. Results from two laboratories and two calibration curves are compared, showing some significant differences in one case. We conclude with an evaluation of the relevance of 14C dating for the current debate about the chronology of the Iron Age in Israel, and in historical periods in general.

Preliminary experiments were carried out on archaeological wood to investigate methods of cellulose hydrolysis and carbohydrate monomer purification for the purpose of compound-specific radiocarbon dating. The Chelford log, a known 14C dead source of wood cellulose, was selected for study in order to investigate the levels of contamination introduced during sample purification. Two methods of hydrolysis were examined, mineral acid hydrolysis and enzyme hydrolysis using cellulase from Penicillium funiculosum. Under the conditions described, enzymolysis was far superior to acid hydrolysis in terms of the glucose monomer yield. Glucose monomer purification was accomplished using high pH anion exchange chromatography with pulsed amperometric detection. This high performance liquid chromatography (HPLC) method does not require sample derivatization and the chromatography products can be collected in water. These characteristics make it potentially well suited to carbon dating applications. 14C dating of chromatographically purified glucose fractions revealed significant levels of contamination had accumulated during both protocols. Glucose contamination from the cellulase enzyme preparation was a major source of contamination within the enzymatically hydrolyzed samples. Ultrafiltration of the enzyme removed some but not all of this contamination. The contamination must be reduced 10-fold before the methodology could be viable for dating. This hydrolysis/HPLC method is also being investigated for 14C dating of other carbohydrate polymers such as chitin.

The first measurements of the fluorescence of liquid organic compounds after excitation with nuclear radiation were published 1948 in a thesis of L Herforth and a paper by Herforth and Kallmann (1949).

A detailed profile of the stable isotopes of carbon and oxygen was obtained from a speleothem (stalagmite) from the Ceremosjna Cave in eastern Serbia. The stalagmite is a low magnesian calcite that did not show any evidence of diagenetic alteration. It was precipitated under isotopic equilibrium conditions from dripping water. The age and rate of deposition was derived from six internally consistent radiocarbon dates. The initial 14C activity was determined to be approximately 80 pMC. The stalagmite appears to preserve a continuous record of calcite deposition from approximately 2300 BP until the present.

Oxygen isotopic data, based upon 100 samples, are used to derive the first paleotemperature record for Serbia. A regression analysis of the all the data indicates that over the period of time that the speleothem was deposited there was a general trend of lowering of the average temperature. Superimposed upon this are significant long-term temperature fluctuations. These can be divided into four broader climatic groupings. Going from the oldest times to the present, there are two warm periods separated by a period when the temperatures fell below the temperature trend line. However, the absolute temperatures were generally above those of the more recent period that is generally characterized by the coolest climatic conditions.

The absolute date of the Iron Age I and IIa periods in Israel, and by inference in the Southern Levant at large, are to date among the hottest debated issues in Syro-Palestinian archaeology. As there are no pegs of absolute chronology throughout this range, conventional chronology had been established on proposed correlations of the material record with events and social phenomena as portrayed in historical and literary sources, chiefly the Hebrew Bible. With the growing impact of so-called “revisionist” notions in Biblical studies, which to various extents question the historicity of the Bible, it is imperative to try to establish a chronological framework for the Iron I–IIa range that is independent of historical and so forth considerations, inter alia in order to be able to offer an independent archaeological perspective of the biblical debate. The most obvious solution is to attempt a radiocarbon-based chronology. This paper explores the possible implications of a sequence of 22 radiometric dates obtained from a detailed Iron I–IIa stratigraphic/ceramic sequence at Tel Dor, on Israel's Mediterranean coast. To date, this is the largest such sequence from any single early Iron Age site in Israel. Having been part of the Phoenician commercial sphere in the early Iron Age, Dor offers a variegated sequence of ceramics that have a significant spatial distribution beyond Phoenicia, and thus transcend regional differences and enable correlation with the surrounding regions. By and large, the absolute dates of these ceramics by the Dor radiometric chronology are up to a century lower than those established by conventional Palestinian ceramic chronology. The ramifications of the lower Dor dates for some Phoenician, Israelite, and Cypriot early Iron Age archaeological issues are explored.