Ernest Anderson, the last of the three scientists responsible for the initial research establishing the validity of the radiocarbon dating method at the University of Chicago in the late 1940s, has died. From early 1947 to the end of 1949, Anderson and James Arnold joined with Willard Libby to undertake three critical experiments, employing what one of them called a “procedure developed in hell” (solid carbon decay counting). They laid the foundation of what has developed over more than 6 decades into the “gold standard” for the chronometric dating of the most recent phases of the technological and cultural evolution of anatomically modern human societies, the geology of the terminal Pleistocene and Holocene, critical events in the history of the Earth's climate over the last 50,000 yr, and a range of other scientific and historical applications.

Dating of Coptic textiles performed in the early days of the radiocarbon dating method was revisited. In 1957–1958, Louvre curator and art historian P du Bourguet had 4 Coptic textiles 14C dated by the Saclay laboratory. The results were rejected, not because of the large standard deviation (>100 yr), but because their ages did not support his chronological framework based on typological comparison. Furthermore, textiles with comparable ages were dated several centuries apart. As a result of this investigation, for many decades art historians rejected 14C as a dating tool for Coptic textiles. Re-examination of the old data and new 14C analyses revealed that mistakes were made, both in the reporting as in the interpretation of the data and that the textiles are much older than presumed.

The present article reports on the results and interpretation of a total of 235 radiocarbon dates from Alpine sites in the Ötztal region. Out of these, 88 age determinations were performed on equipment and artifacts associated with the Neolithic Iceman (discovered in 1991), and on a variety of plant and animal specimens collected at his discovery site. Since the material was dispersed over a larger area, 14C dates were important to establish the deposition time of the respective samples. About half of the samples fall into the time period where the Iceman lived, documenting synchronous deposition, whereas the others spread out over several thousand years before and after his lifetime. The other set of samples (147) were collected along the Ötztal Valley to the north, with a few samples collected also south of the Alpine watershed. The samples were mainly from soil profiles and peat bogs above the present-day timberline. Overall, the analysis of the data indicates human presence in these high regions of the Alps throughout the Holocene. While the older botanical and archaeological finds indicate activities of hunting and foraging, the younger ones (after ∼5000 BC) point to an intensification of pasturing. This suggests that early human activity was concentrated at altitudes where natural pastures were found, which were probably more favorable than locations at the bottom of the valleys where flooding and other hazards existed. Early users may have come from south of the water divide spreading into the northern regions, particularly during the summer season. It is possible that the Iceman perished at one of his crossings over the probably well-known high-altitude mountain pass due to reasons not yet fully resolved.

Human history has been marked by major episodes of climate change and human response, sometimes accompanied by independent innovations. In the Bronze Age, the sequencing of causes and reactions is dependent in part on dendrochronology and radiocarbon dating. This paper explores the interaction of a major, prolonged desiccation event between c. 2300 and 2000 BC and human agency including migrations, the displacement of trading networks, warfare, the appearance of weapons made of bronze, and the first appearance of sailing vessels in the Mediterranean.

This study investigates the accuracy of the radiocarbon-based calculation of the biogenic carbon fraction for different biogas and biofossil gas mixtures. The focus is on the uncertainty in the 14C reference values for 100% biogenic carbon and on the 13C-based isotope fractionation correction of the measured 14C values. The separately (AMS) measured CO2 and CH4 fractions of 8 different biogas samples showed 14C values between 102‰ and 116% (pMC). The δ13C values of these samples varied between –6‰ and +31‰ for the CO2 fraction and between –28‰ and –62‰ for the CH4 fraction. The uncertainty in calculated biogenic carbon fractions due to uncertainty in the 14C reference values depends on the available information about the origin of the used biogenic materials. It varies between ±0.5% and ±3.5% (absolute) depending on the type of biogas. A method is proposed to minimize this uncertainty for different groups of biogases. The calculated biogenic carbon fraction deviates up to ±2.5% for biofossil gas mixtures, if the applied isotope fractionation correction is based on the δ13C value of the mixed biofossil sample instead of the biogenic δ13C value. Combination of both error sources shows that the uncertainty in the calculated biogenic carbon fraction varies between ±0.7% and ±4.5%, depending on the type of biogas in the sample.

The Son Ferrer archaeological site presents a series of successive occupations spanning a long period of time. At the beginning of the Iron Age (∼850 BC), a staggered turriform structure was built for a ritual purpose over an artificial hypogeum that had already been used as a collective necropolis during the Early Bronze Age (∼1800–1500 BC). Later, in the post-Talayotic phase (Second Iron Age, 550–123 BC), the hypogeum was again reused as a collective burial place. The present work is focused on the chronological and functional analysis of this last phase, which began ∼500 BC and ended ∼180 BC with the saturation and sealing of the hypogeum. The excavation process revealed that significant removal of archaeological material has occurred as a result of complex funerary space management practices, which generated a secondary archaeological context. Given this situation, and in order to establish the different use phases of the post-Talayotic necropolis, a dual strategy of excavation and research was implemented. First, an extensive series of radiocarbon dates on human remains (18 dates) was obtained, which were later analyzed following Bayesian strategies. Second, a detailed spatial analysis was carried out, georeferencing the location of all the archaeological finds. This strategy allowed the reconstruction of the space management processes and movement patterns that took place in the burial space. Despite some initial difficulties, the combination of these research strategies embedded in a contextual analysis provided both material and chronological references that have contributed to define the various use phases of the hypogeum.

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.

Carbonate is abundant in many Neolithic tells and is a potentially useful archive for dating and climate reconstruction. In this paper, we focus on the mineralogy, radiocarbon dating, and stable isotope systematics of carbonate in hackberry endocarps. Hackberry fruits and seeds are edible in fresh and stored forms, and they were consumed in large quantities in many Neolithic sites in the Near East, including the site of our study, Aşıkli Höyük in central Anatolia, an Aceramic Neolithic tell occupied from about 9.4 to > 10.3 BP (7.4 to > 8.3 BCE). Detailed 14C age control provided by archaeological charcoal permits a test of the fidelity in 14C dating of hackberry endocarps. Modern endocarps and leaves yield fraction modern 14C values of 1.050–1.066, consistent with levels present in the atmosphere when sampled in 2009. On the other hand, archaeological endocarps yield consistently younger ages than associated charcoal by ca. 130 14C years (ca. 220 calendar years) for samples about 10,000 years old. We speculate this is caused by the slight addition of calcite or recrystallization to calcite in the endocarp, as detected by scanning electron microscopy. Subtle addition or replacement of calcite by primary aragonite is not widely recognized in the 14C community, even though similar effects are reported from other natural carbonates such as shell carbonate. This small (but consistent) level of contamination supports the usefulness of endocarps in dating where other materials like charcoal are lacking. Before dating, however, hackberries should be carefully screened for mineralogical preservation and context. We examined the carbon and oxygen isotopic systematics of the fossil endocarps to try to establish potential source areas for harvesting. Most of the hackberries are enriched in 18O compared to local water sources, indicating that they were drawing on highly evaporated soil water, rather than the local (perched and regional) water table sampled in our study. Isotopic evidence therefore suggests that most but not all of the hackberries were harvested from nearby mesas well above the local streams and seeps fed by the water table.

The present article comprises a multidisciplinary archaeometric approach for the study of Hellenistic and Early Roman kilns in Greece. A collection of previously published and new archaeomagnetic data are combined with new results from mineralogical analytical experiments. The sampled material came from four areas, covering different geological contexts: Katerini, Olympiada, and Polymylos in mainland Greece, and the island of Paros. Extensive rock-magnetic experiments, including identification of the dominant ferromagnetic minerals present, their domain state, and mineralogical alterations during laboratory treatments, have been carried out in order to examine the magnetic properties of the studied materials and prove their suitability for reliable archaeomagnetic determinations. Magnetic cleaning provided well-defined archaeomagnetic directions, and archaeointensity measurements were carried out using both the Thellier-Thellier and Triaxe protocols. Information from both magnetic and mineralogical properties referring to firing conditions is further discussed along with archaeological information. Finally, a new dating of the four sites together with other structures of similar age was carried out using the Pavón-Carrasco model.

The Balearic Islands provide a good example of late human settlement in the context of the prehistoric Mediterranean. After what could be considered a period of colonization, the earliest autochthonous cultural manifestations occur in the Bronze Age. This study aims to outline a chronology for Balearic Bronze Age villages, based on the case study of S'Hospitalet Vell (Manacor). A wide radiocarbon record has been obtained from three different habitation structures at the site. By combining the available dates with the stratigraphical information, a chronological approach to the occupation dynamics of this site can be established.

The fractionation correction b is used to correct for the fractionation of 14C by using information from 13C in samples. This value is assumed to have a value of 2, where the 14C/12C ratio is double that of the 13C/12C ratio. While natural and laboratory fractionation are usually not considered separately, this article explores the differential fractionation of 14C and 13C during the process of photosynthesis. Values of δ13Cp can be used to calculate Δ13Cp values, which in turn can be used to calculate Δ14Cp, the discrimination against 14CO2 during photosynthesis. Models can then be built of Δ14Cp/Δ13Cp, an approximation for the natural fractionation ratio. This approximation suggests that for C3 plants the ratio is ∼1.90 and for C4 plants the ratio is more variable. While error introduced by the natural fractionation is small, it is also possibly systematic, as b = 2.0 does not seem physiologically possible following these models of carbon fractionation during photosynthesis. The central aim of this study is to illustrate that b derives not from a natural constant, but rather from a variable natural process.

AMS-bascd radiocarbon dating was applied to Medieval lime mortars made from burned shells and aggregate including both shore sediments and neovolcanic rocks. Three mortar samples from the city of Leiden near Amsterdam were prepared using the same kind of acid hydrolysis technique as has been earlier used for dating mortars made from burned marble and limestone. Five consecutive CO2 fractions were collected from each sample to form age profiles as functions of the dissolution progress index. One of the samples, from a brick wall of known age, was taken as a reference from the Pieterskerk church. Two other samples were taken from the Burcht circular stronghold on a former island on the Rhine River. The age of Burcht is less well known; thus, the presented results are a contribution to an ongoing discussion on its history.