In order to radiocarbon (14C) date a building, several components of the mortar could be used, such as the mortar binder, the lime lumps, the charcoal particles and shell fragments eventually present among the aggregates. In particular, the mortar binder requires a purification treatment in order to separate it from other sources of carbon, which could change the 14C signature of the binder invalidating the dating process. Here, we present the application of the Cryo2Sonic method to 14C dating of the ancient building structures unearthed during excavation at the Padua Cathedral complex. The dated samples were pretreated by using Cryo2Sonic method and the improved Cryo2Sonic version 2.0, recently developed by introducing additional steps such as centrifugation of the mortar suspension and gravimetric sedimentation of the binder fractions. The Cryo2Sonic version 2.0 relies heavily on the characterization of the mortar and of the purified binder fractions, allowing the isolation of a reliable 14C datable mortar fraction. Through this new method, the 14C dating of different ancient structures excavated next to the Padua Cathedral allow to identify the first religious complex of the city of Padua (3rd–4th centuries AD).

This work aims to test the reliability of calcined bones for radiocarbon dating of the Paleolithic. Fifty-five calcined bone samples coming from Aurignacian and Gravettian layers at Abri Pataud (Dordogne, France) were selected based on their macroscopic features. For each sample, the heating state was estimated on the basis of bone crystallinity (splitting factor [SF] using FTIR) and δ13C value. Twenty-seven bone samples (3 unburnt and 24 calcined) from 5 different levels were prepared for 14C dating. The majority (15/24) of the calcined samples had to undergo a sulfix treatment prior to graphitization, probably due to the presence of cyanamide ion in these samples. The comparison between our results and recently published dates on bone collagen for the same levels shows that unburned bone apatite is systematically too young, while a third of the calcined bones fall within or very near the range of expected age. No clear correlation was found between 14C age offset and δ13C value or SF. Most of the sulfixed samples (14/16) yielded ages that were too young, while almost all of the non-sulfixed samples (8/9) gave ages similar or <0.2 pMC from the expected minimum age. Although preliminary, these results suggest that sulfix should be avoided if possible and that clean CO2 gas from well-calcined Paleolithic bones can provide reliable 14C ages.

Using the model of Stacker and Wright (1996), we investigate the effect of a succession of ocean ventilation changes on the atmospheric concentration of radiocarbon, δ14Catm, the surface reservoir ages, the top-to-bottom age differences, and the calendar-14C age relationships in different regions of the ocean. The model includes a representation of the cycling of 14C through the atmosphere, the ocean and the land biosphere. Ocean ventilation changes are triggered by increasing rates of freshwater discharge into the North Atlantic, which are determined according to a simple feedback mechanism between the melting rates and the climatic state of the North Atlantic region. The results demonstrate that ventilation changes can cause δ14Catm fluctuations of 25%, surface reservoir age fluctuations of 100 yr in the Pacific (200 yr in the Atlantic) and top-to-bottom age variations of 500 yr in the Pacific (1000 yr in the Atlantic). We also show that 14C age estimates based on marine organisms that live in the near-surface region of the ocean and take up the signal of surface 14C can result in apparent age reversals if the assumption of a constant reservoir age is made.

We present results of 14C dating of several tree-ring series from the Late Glacial and Early Holocene, analyzed at the Heidelberg University radiocarbon laboratory. Although these are floating series, they contribute high-resolution information about the variability of atmospheric 14C during those periods.

Deposits from the Minoan Santorini (Thera) eruption in the eastern Mediterranean region constitute the most important regional stratigraphic marker in the chronological perplexity of the 2nd millennium BCE. Extensive tsunami deposits were discovered in Crete at the Minoan archaeological site of Palaikastro, containing reworked volcanic Santorini ash. Hence, airborne deposition of volcanic ash, probably during the 1st (Plinian) eruption phase, preceded the tsunami, which was apparently generated during the 3rd or 4th phase of the eruption, based on evidence from Thera. Average radiocarbon dates (uncalibrated) of animal bones in the Palaikastro tsunami deposits along the coast (3350 ± 25 BP) and at the inland archaeological site (3352 ± 23 BP) are astoundingly similar to the average 14C date for the Minoan Santorini eruption at Akrotiri on Thera (3350 ± 10 BP). The wiggle-matched 14C date of the eruption in calendar years is 1627–1600 cal BCE. Late Minoan IA pottery is the youngest element in the Palaikastro tsunami deposits, fitting with the LM IA archaeological date for the Santorini eruption, conventionally linked at ~1500 BCE with Dynasty XVIII of the historical Egyptian chronology. The reasons for the discrepancy of 100–150 yr between 14C dating and Egyptian chronology for part of the 2nd millennium BCE are unknown. 14C dates from Tell el-Dabca in the eastern Nile Delta show that the 14C age of the Santorini eruption matches with 14C results from 18th Dynasty strata C3 and C2, thereby confirming grosso modo the conventional archaeo-historical correlations between the Aegean and Egypt. We propose that a dual dating system is used in parallel: (1) archaeological material-cultural correlations linked to Egyptian chronology; (2) 14C dating. Mixing of dates from the 2 systems may lead to erroneous archaeological and historical correlations. A “calibration curve” should be established between Egyptian chronology and 14C dating for the 2nd millennium BCE, which may also assist to resolve the cause of the discrepancy.

The radiocarbon dating of volcanic ash (tephra) deposits in New Zealand has been difficult on sites remote from the eruption, which contain either little carbon or degraded and contaminated charcoal. Although many studies of contamination removal from macroscopic charcoals from tephra sequences have been made, little attention has been paid to those containing no visible charcoal, because of the difficulty of obtaining sufficient carbon for radiometric dating. We report here experiments using accelerator mass spectrometry to establish a reliable method for dating a low-carbon aeolian and peat deposit containing a tephra horizon. Results so far demonstrate that improvements to existing chemical pretreatment methods are possible, and that dates obtained on oxidized fine-grained residues can approach the maximum age determined on good quality charred wood samples.

ΔR results of known-age shells from the Solomon and Coral Seas and the northwest coast of New Ireland are presented. The results are too few to be conclusive but indicate that ΔR in this region is variable. An average ΔR value of 370 ± 25 yr is recorded for a range of shell species from Kavieng Harbor, New Ireland, and is primarily attributed to weak equatorial upwelling of depleted 14C due to seasonal current reversals. In contrast, values from the Solomon and Coral Seas are lower (average ΔR = 45 ± 19 yr). Higher ΔR values for some shellfish from these 2 seas is attributed to ingestion of 14C-depleted sediment by deposit-feeding species.

Radiocarbon-age measurements reported here were made by the carbon dioxide gas-proportional counting method since conversion of the laboratory from the solid-carbon method. Assembly of the shield and construction of the glass system was accomplished during the summer of 1959. By January 1960, shield, anticoincidence ring, counters and electronics were set up and in operation. The first year of operation was occupied with calibration, comparison of dating with other C14 laboratories, and the repeating of many of the analyses previously made by the solid-carbon method. Special attention was given to dates open to question from an archaeologic point of view.

Bi-decade samples of dendrochronologically matched Irish Oak, measured with a precision of ca ± 20 years, covering the period 200 to 4000 BC are presented. The data are compared with the published data of Suess, de Jong, and Mook to provide a general calibration of the 14C time scale for this period. Although the dendrochronologic sequences presented are not absolutely tied to present, the best fit (based on 14C evidence) of the Belfast data to absolute chronologies, the error and evidence associated with such positioning is given. The intervals chosen for analysis were 20 years, reducing slightly the resolution of short-term variations when compared to 10-year intervals, which are sometimes measured. However, this calibration would suffice for most scientific purposes and certainly for the calendrical conversion of 14C dates derived from archaeologic samples.

Four different bone collagen preparation procedures were compared and were found useful as a means of assessing the nature of contaminants present in a sample. Weathered bone however appeared to contain contaminants that could not be eliminated by any of the procedures studied.

The third series of radiocarbon measurements made at the British Museum Research Laboratory is reported in the following list. Equipment and method used are as described previously (British Museum I) and, as in previous lists, the error terms are not based solely on counting statistics, but are widened to include contributions of ±80 years for possible isotopic fractionation effects and ±100 years for the de Vries effect. Ages are calculated on a half-life of 5568 ± 30 years. NBS oxalic acid is now used as a reference standard in place of 100-yr-old oak. The latter gave an age-corrected value almost exactly 95% of the oxalic-acid activity and thus no corrections are required to our previous date lists to bring them into line with the new standard.

A new method is presented for the reconstruction of the radiocarbon production rate from the measured relative abundance of Δ14C. The method treats the carbon cycle as a linear Fourier filter and thus allows for the correct and unambiguous inversion of the carbon cycle. The 14C production rate, as reconstructed by the Fourier filter method, agrees with the results obtained by the traditional iteration method. Since the 2 methods use completely different approaches, this verifies the validity of the reconstruction. The composite series is presented, based on both methods and their systematic uncertainties.

Radiocarbon activity of 11 modern marine shell samples from the New Zealand region is enhanced compared with the surface layers of the average world ocean. The measured enhancement, δR, is equivalent to −31 ± 13 years. On this basis, the Institute of Nuclear Sciences will now use a value of −30 years in reporting calibrated ages for marine shell samples.

Progressive dissolution experiments were performed on samples of ostracode shells from lacustrine sediments from the western Great Basin to remove contamination of the surface by secondary calcite. The observed age differences between the external and residual fractions were as great as 2000 to 6000 yr. A “plateau” in ages of the last fractions was obtained only for 1 sample; however, results of repeated experiments resulted in very good agreement of the final ages. A comparison with previously published chronologies based on bulk radiocarbon ages of ostracodes from Wilson Creek (Benson et al. 1990) shows that leaching is imperative for dating samples older than 20 ka B P. This study focuses on the problem of contamination and its removal. However, the final chronology of the Wilson Creek Formation (and other late Pleistocene lacustrine sediments) will require additional dating of other sections as well as establishment of a reservoir effect correction.

This article focuses on constructing a high-resolution age-depth model for the Puścizna Mała peat bog located in Orawa-Nowy Targ Basin (S Poland). The chronology was established on the basis of both 210Pb and 14C measurements, and further confirmed by pollen diagrams and the peat bulk composition (density, ash content, and measurements of C, N, S). The 137Cs profile revealed significant downward migration of this radionuclide and was not suitable for geochronological interpretation. The peat profile in southern Poland records almost 2000 yr of paleoecological and geochemical changes. Major historical events linked to anthropogenic and climatic changes are recorded in the investigated proxies, which confirm the reliability of the age-depth model. Specifically, the Roman period, Migration period, Medieval times, as well as the Industrial Revolution are reflected in the palynology and bulk composition of the peat. However, dating results obtained for the core segment between 22–45 cm are problematic when confronted with other analyses. The highest peat accumulation rate of 2 mm yr-1 (AD 1300–1400 according to the age-depth model) is not compatible with the section of the highest peat decomposition revealed by lithological description. Moreover, the onset of a drastic decline of forests reflected in the palynological data and dated to AD 1280–1340 (40 cm) is difficult to explain in the light of historical data. Therefore, the lithology, bulk density, and pollen were used to validate the obtained age-depth model. External forcing factors on the peat formation process may be indicated, including agricultural activity, water-level fluctuations, and natural climatic factors, which paradoxically caused doubling of the obtained peat accumulation rate.

The freshwater reservoir effect is a potential problem when radiocarbon dating fish bones, shells, human bones, or food crusts on pottery from sites near rivers or lakes. The reservoir age in hardwater rivers can be up to several thousand years and may be highly variable. Accurate 14C dating of freshwater-based samples requires knowing the order of magnitude of the reservoir effect and its degree of variability. Measurements on modern riverine materials may not give a single reservoir age correction that can be applied to archaeological samples, but they show the order of magnitude and variability that can also be expected for the past. This knowledge will be applied to the dating of food crusts on pottery from the Mesolithic sites Kayhude at the Alster River and Schlamersdorf at the Trave River, both in Schleswig-Holstein, northern Germany.

The C14 measurements reported here were made in this laboratory between November 1, 1963 and November 15, 1965. Sample descriptions are classified as follows:

1. I. Geochemical Samples

2. II. Geologic-Paleoclimatic Samples

3. III. Early Man-Alluvial Stratigraphy Samples

4. IV. Archaeologic Samples

A two-decade-long record of environmental isotopes (2H, 3H, 14C, 18O) in Croatia is presented and the data are statistically analyzed. The atmospheric 14C activity for the period before the actual measurements started is reconstructed by measuring tree rings from the clean-air sites, and the past tritium activity in precipitation is estimated by the correlation of our data with the Vienna station record. The long-term 3H record helped to determine a locally contaminated sampling site, and new clean sites are put into operation. The 14C data were fitted by an analytical function and the prediction of future levels is given assuming that the rate of the 14C releases remains constant. From the long-term stable isotope data record, the local meteoric water line and the temperature gradient of δ18O in precipitation are determined.

Large sets of radiocarbon dates of 1019 peat, 155 speleothem, and 100 tufa samples, as well as dates of 330 fluvial samples, were investigated in order to estimate environmental variability during the last 16,000 calendar years in Poland. All 14C dating was carried out in the Gliwice Radiocarbon Laboratory, and results are stored in the RoS database. Probability density functions (PDFs) were created by summing up (on the calendar timescale) individual age probability distributions of all dates for different types of material and for different regions of Poland. We used an updated version of the Gliwice Radiocarbon Laboratory calibration program GdCALIB. The 14C dates were calibrated using the IntCal04 calibration curve (Reimer et al. 2004), and results were compared with other paleoenvironmental records. The authors conclude that analyzing PDFs of different types of sediments can be helpful in the qualitative reconstruction of the past environment. The PDF for peat samples primarily reflects paleohydrological conditions; the PDFs for speleothem and tufa samples reflect changes in temperature and humidity, while analysis of the PDF created for fluvial data is in a general agreement with the PDFs constructed for peat samples.