Radiocarbon Reservoir Effects

The date and location of the earliest chapel on the Hailuoto Island is examined by reviewing the archaeological and geological data gathered in late 1980s, on which the original hypothesis about the existence of the early 14th century AD ecclesiastic building at the site of the ‘Old Church’ stood on. As old wood and marine reservoir effects were unrecognised back then, the calibrated radiocarbon dates gave systematically older date estimates. The coin evidence suggests a mid-15th century AD terminus post quem, while the preserved wooden statuettes of saints date to the late 15th century AD. As the data regarding local land-uplift rate is today more reliable than in 1980s and precise information on elevation gathered with airborne LiDAR can be analysed using the GIS, a new reconstruction regarding the environment around the ‘Old Church’ is also presented. Finally, reasons for further archaeological research on Hailuoto are sketched in brief.

Direct dates of pottery obtained from food crusts or other organic residues on the vessel surfaces can be affected by a reservoir effect and/or an old wood effect and therefore be unreliable. Hence, there is a need for alternative ways to directly date pottery. Moss is used as temper by several cultural groups of the late 6th to early 4th millennium cal BC in northwestern Europe. After the pottery is fired, charred moss remains are often preserved in the clay, so that relatively short-lived plant material with a direct chronological link to the pottery and human occupation is available for radiocarbon (14 C) dating. In this study, charred moss temper is extracted for accelerator mass spectrometry (AMS) 14 C dating from pottery of the Swifterbant Culture and Michelsberg Culture/Group of Spiere in the Scheldt river valley (Belgium). The moss dates are then compared to reference dates of organic macro-remains from the same sites and food crust dates with or without a reservoir effect of the same pottery. Eleven out of 13 moss dates are in line with the expected pottery age. The paired dates of moss temper and food crusts from the same potsherds confirm a freshwater reservoir effect (FRE) for the latter. We conclude that moss temper has great potential as a sample material for direct pottery dating. However, more research on the extraction and pretreatment of moss temper as well as on the reliability of moss dates is necessary in the future.

Accurately dating when people first colonized new areas is vital for understanding the pace of past cultural and environmental changes, including questions of mobility, human impacts and human responses to climate change. Establishing effective chronologies of these events requires the synthesis on multiple 14 C dates. Various 'chronometric hygiene' protocols have been used to refine 14 C dating of island colonization, but they discard up to 95% of available 14 C dates leaving very small datasets for further analysis. Despite their foundation in sound theory, without independent tests we cannot know if these protocols are apt, too strict or too lax. In Iceland, an ice-core dated tephrochronology of the archaeology of first settlement enables us to evaluate the accuracy of 14 C chronologies. This test demonstrated that the inclusion of wider range of samples for 14 C dates in Bayesian models improves the precision, but does not affect the model outcome. Therefore, based on our assessments, we advocate a new protocol that works with a much wider range of samples and where outlying 14 C dates are systematically disqualified using Bayesian Outlier Models. We show that this approach can produce robust termini ante quos for colonization events and may be usefully applied elsewhere. 2

We report here on a comprehensive radiocarbon dating program to date the age of the Kwädąy Dän Ts’ìnchį man. The individual was found in association with a number of artifacts, including a plant fibre hat, a robe-style fur garment and various wooden items. The first series of radiocarbon dates on this associated material ranged from 500 to 120 Before Present, indicating that the area is a multi-phase site where various organic objects were deposited over at least a 400 radiocarbon-year time period. Of these, two initial conventional radiocarbon dates on clothing—a hat and robe fragment—directly associated with the Kwädąy Dän Ts’ìnchį man indicated that the individual was at least 550 years old: Arctic Ground Squirrel fur from the robe, 450 ± 40 BP; the hat’s split-root plant fibre, 500 ± 30 BP. To confirm the dating of this individual and better clarify the ages of the associated material culture, we undertook  additional radiocarbon dating, including two separate dates directly on the individual himself. We also re-dated the hat and robe fragments reported earlier, obtaining dates that were younger than initially reported but similar to the new dates we obtained on associated artifacts and on the Kwädąy Dän Ts’ìnchį man himself.

Updated calibrated dates of the radiocarbon ages from the Neolithic settlement Ftelia on Mykonos (25􀁱 22΄ 30΄΄ E, 37􀁱 27΄ 30΄΄ N) using the latest issues of the international calibration curves INTCAL13 and MARINE13 allowed the calculation of the "marine reservoir effect" R(t) and the local marine reservoir deviation ΔR values in the Cyclades during the Neolithic period. These were found to be R(t) -26 ± 96 yr and ΔR = -400 ± 113 14C yr, The obtained calibrated dates showed that the site was occupied during the Late Neolithic period for about six centuries [5051-4457 BC, (7000-6406 cal BP), 1σ].

Sacred Ibis (Threskiornis aethiopicus) were widespread in Egypt until the eighteenth century. Today the species is extinct in modern Egypt but millions of mummified specimens are scattered geographically in dedicated Ibis burial sites throughout the country. Ibises were regarded as physical manifestations of the god Thoth and worshiped by the ancient Egyptians. A small number of Sacred Ibis were chosen as ‘sacred animals’, based on physical markings, and were reared for the temples. However, the majority of the mummified Sacred Ibis were ‘votive animals’ that were given as offerings to the deities by pilgrims, and then buried in catacombs associated with the temple. Their supply became an industry that is thought to have flourished from the Late Period, well into the Roman Period (c. 664 BC to AD 350). Dating of the Sacred Ibis mummies, as well as other mummified animal specimens, has been based on archaeological evidence such as the age of catacombs, the design of enclosures and the shape of the mummy containers (pottery jars, wooden chests or stone boxes). Here we present the first ages of a selection of Sacred Ibis mummies using 14C methods in order to establish how closely they match the archaeological chronology. Dates are reported from museum samples provenience from Saqqara, Roda and Thebes. Our 14C radiocarbon results date the Ibis mummies between c. 450 and 250 cal BC and represent a short period of time. Those dates are falling from the Late Period to the Ptolemaic Period at maximum. Surprisingly, none of the samples were dated to the Roman era.

Freshwater reservoir offsets (FROs) occur when AMS dates on charred, encrusted food residues on pottery predate a pot's chronological context because of the presence of ancient carbon from aquatic resources such as fish. Research over the past two decades has demonstrated that FROs vary widely within and between water bodies and between fish in those water bodies. Lipid analyses have identified aquatic biomarkers that can be extracted from cooking residues as potential evidence for FROs. However, lacking has been efforts to determine empirically how much fish with FROs needs to be cooked in a pot with other resources to result in significant FRO on encrusted cooking residue and what percentage of fish C in a residue is needed to result in the recovery of aquatic biomarkers. Here we provide preliminary assessments of both issues. Our results indicate that in historically-contingent, high alkalinity environments <20% C from fish may result in a statistically significant FRO, but that biomarkers for aquatic resources may be present in the absence of a significant FRO.

The onset of the Neolithic period in the Russian North is defined by the emergence of pottery vessels in the archaeological record. The ceramics produced by mobile hunter-gatherer-fisher groups in the northeastern European forest zone are among the earliest in Europe, starting around 6000 cal BC. After the initial mosaic of local styles in the Early Neolithic, including sparsely decorated wares and early Comb Ware, the Middle Neolithic period, starting in the 5 th millennium cal BC, saw the development and spread of larger, more homogenous typological entities between the Urals and the Baltic, the Comb-Pit and Pit-Comb wares. Absolute chronologies, however, are still subject to debate, due to a general lack of reliable contextual information. Direct 14 C dating of carbonised surface residues ('food crusts') on pots can help to address this problem, as it dates the use of the pottery; but if aquatic foods were processed in the vessels, the respective radiocarbon ages can appear to be too old due to the freshwater reservoir effect. In this paper , we discuss the radiocarbon chronologies of four important stratified archaeological complexes in the region between Lake Onega and the Sukhona basin, Berezovaya Slobodka, Veksa, Karavaikha, and Tudo-zero. A growing series of dates, including AMS dates, sheds new light on the onset and further periodisation of the Early and Middle Neolithic in this important area between Eastern Fennoscandia, Central Russia and the Far NorthEast of Europe, although problems concerning the absolute chronology of the initial Neolithic remain.

A B S T R A C T AMS-radiocarbon measurements of amino acids can potentially provide more reliable radiocarbon dates than bulk collagen analysis. Nonetheless, the applicability of such an approach is often limited by the low-throughput of existing isolation methods and difficulties in determining the contamination introduced during the separation process. A novel tertiary prep-HPLC amino acid isolation method was developed that relies on the combustion of eluted material without requiring any additional chemical steps. Amino acid separation was carried out using a gradient mix of pure water and phosphoric acid with an acetonitrile step in-between runs to remove hydrophobic molecules from the separation column. The amount of contaminant carbon and its 14 C content were determined from two-point measurements of collagen samples of known 14 C content. The amount of foreign carbon due to the isolation process was estimated at 4 ± 1 μg and its 14 C content was 0.43 ± 0.01 F 14 C. Radiocarbon values corrected for carbon contamination have only a minor increase in uncertainties. For Holocene samples, this corresponds to an added uncertainty typically smaller than 10 14 C years. The developed method can be added to routine AMS measurements without implying significant operational changes and offers a level of measurement uncertainty that is suitable for many archaeological, ecological, environmental, and biological applications.