Radiocarbon (14C) activity in groundwater can be used to determine subsurface residence time up to ∼40 kyr, providing crucial information on dynamic properties of groundwater and on paleoclimate. However, commonly applied sampling methods for dissolved inorganic carbon (DIC-14C) are prone to low level of modern atmospheric contamination, resulting in underestimation of groundwater ages that cluster around 30–40 kyr. We extract CO2 gas from groundwater using a device originally developed for studies of noble gas radionuclides. Carbon is collected in the gas phase, eliminating the possibility of fostering microbial activities and aqueous chemical reactions during sample storage. This method collects CO2-14C and radiokrypton (81Kr and 85Kr) samples simultaneously. The presence of any shorter-lived 85Kr is used to evaluate the degree of atmospheric contamination during sampling or mixing of young groundwater. Most groundwater samples showed lower CO2-14C activities than those of DIC-14C, presumably due to the absence of atmospheric contamination. Samples with 81Kr age exceeding 150 kyr have no detectable CO2-14C except where mixing sources of young groundwater is suspected. These field data serve as confirmations for the reliability of the newly presented sample collection and CO2-14C method, and for the outstanding roles of radiokrypton isotopes in characterizing old groundwater.

We present radiocarbon (14C) measurements of dissolved inorganic carbon (DIC) from surface waters of 11 lakes, widely distributed in China. Surface lake water DIC F14C values show distinct differences, and we relate these to the physical exchange character (“open” or “closed”) of each lake. Open lakes studied here generally have lower DIC F14C values than closed lakes. We present a simple model of a lake water cycle to calculate an average residence time for each lake. Comparisons between lake DIC F14C and average residence time shows that the DIC F14C increases with the average residence time and reflects a steady-state.

The study the diet of Eneolithic populations is of great interest to archaeologists. However, the studies undertaken in the steppe and forest-steppe zones of Volga region in Russia have left many issues unsolved. Data collected recently through the comprehensive studies of Lebyazhinka VI settlement enable us to change this situation. Of particular importance at this settlement site is good preservation of animal bones, bone fishing tools, and ceramics of the same type with food crusts and connected to a large house pit. For the first time in this geographical area, bones of domestic animals were found in the fill of a dwelling. The aim of this paper is to present the results obtained through comprehensive studies of diet and economy in the Eneolithic based on the materials from Lebyazhinka III and Lebyazhinka VI settlement sites. The main results of the archaeozoological analysis— determinations of species, age and size of the animals—provide the necessary data for studying the diet. We conclude that there are differences between Lebyazhinka III and Lebyazhinka VI settlements. Lebyazhinka III settlement included bones of only wild species, however, Lebyazhinka VI settlement consists of wild and domestic species.

During the last several years, new multi- and single-layered archaeological sites, in which the most ancient Neolithic pottery in the Eastern Europe had been found, were excavated in the region of Lower Volga. Animal bones and organic materials were sampled from these sites for radiocarbon (14C) dating and diet investigations. The evidence from these studies suggests that the first domestic animals in the Lower Volga region appeared in the Cis-Caspian culture of the Early Eneolithic. Lipid analysis of food crusts from pottery allowed the cooked food to be characterized. The detailed chronology from Neolithic (6500–5400 cal BC) to Eneolithic (5300–4700 cal BC) cultures, as well as the diet of these ancient people, were reconstructed.

The chronology of human presence in Chontales, central Nicaragua, was established by Franck Gorin (1989), who applied a combination of absolute dates and ceramic associations to build a sequence comprised of six different phases. However, interpretative and chronological issues have arisen due to two main problems. First, the sequence was based on stylistic associations to polychrome ceramics from Pacific Nicaragua. Second, the sample analyzed by Gorin shows contextual bias and lacks sufficient absolute dates. As a result, a comprehensive regional research plan was established to test the current accepted chronology, and redefine it where necessary. In this paper, we present the first date list for the Valley of Juigalpa, Mayales River subbasin (Chontales, Nicaragua). Contrary to Gorin’s proposal, which established a chronology from 500 BC through AD 1600, reports on new seventeen radiocarbon (14C) assays show a cultural sequence from 1420 ± 30 BP, or cal AD 595–660 (±2σ) through the present.

New paleodietary data were obtained after the discovery and excavation in 2015–2017 of the Cherepakha 13 site in the southern part of Primorye (Maritime) Province in far eastern Russia. The site is located near the coast of Ussuri Bay (Sea of Japan) and belongs to the Yankovsky cultural complex of the Early Iron Age 14C-dated to ca. 3000 BP (ca. 1200 cal BC). The stable isotope composition of the bone collagen for 11 humans and 30 animals was determined. For humans, the following values (with±1 sigma) were yielded: δ13C=–10.2±0.8‰; and δ15N=+12.4±0.3‰. The majority of terrestrial animals show the usual isotopic signals: δ13C=–19.4 ÷ –23.3‰; and δ15N=+4.6÷+6.6‰ (for wolves, up to +10.1‰); dogs, however, have an isotopic composition similar to humans: δ13C= –11.7±1.2‰; and δ15N=+12.4±0.4‰. Marine mammals have common values for pinnipeds: δ13C=–13.7 ÷ –14.6‰; and δ15N=+17.4 ÷ +18.0‰. The main food resources for the population of Cherepakha 13 site were (1) marine mollusks, fish, and mammals; and (2) terrestrial mammals; and possibly C4 plants (domesticated millets).

Recent studies have shown that faunal assemblages from Mesolithic sites in inland Northern Europe contain more fish remains than previously thought, but the archaeological and archaeozoological record does not reveal the dietary importance of aquatic species to hunter-gatherer-fishers, even at a societal level. For example, the function of bone points, as hunting weapons or fishing equipment, has long been debated. Moreover, traditional methods provide no indication of variable subsistence practices within a population. For these reasons, paleodietary studies using stable isotope analyses of human remains have become routine. We present radiocarbon (14C) and stable isotope data from nine prehistoric human bones from the Early Mesolithic-Early Neolithic site of Friesack 4, and isotopic data for local terrestrial mammals (elk, red deer, roe deer, wild boar, aurochs, beaver) and freshwater fish (European eel, European perch). The reference data allow individual paleodiets to be reconstructed. Using paleodiet estimates of fish consumption, and modern values for local freshwater reservoir effects, we also calibrate human 14C ages taking into account dietary reservoir effects. Although the number of individuals is small, it is possible to infer a decline in the dietary importance of fish from the Preboreal to the Boreal Mesolithic, and an increase in aquatic resource consumption in the Early Neolithic.

Consumption of marine protein in humans and animals can result in an apparent older radiocarbon (14C) age due to reservoir offsets. In order to correct for this, an estimate of the marine protein intake should be used to correct the 14C age for reservoir offsets, which is ordinarily done using δ13C or δ15N values. However, these two isotopic proxies can be influenced by a number of factors which can hamper estimation of the correct marine protein intake. A small dataset of 12 samples from the Limfjord, Denmark, ranging in age from Mesolithic to Viking Age, was used to test the use of δ2H values to quantify marine protein intake and determine the reservoir corrections. Each of the three stable isotopic values (δ2H, δ13C, δ15N) was used to estimate the percent marine protein intake, which produced three different calibrated 14C ages. The calculated percent marine protein intake differed between the use of the stable isotopic ratios with a maximum difference of 42.1% between the use of δ15N and δ13C, 23.8% between δ2H and δ13C, and 46.2% between δ2H and δ15N. In some cases the calculated percent marine protein intake changed the sample’s archaeological period, although there was generally still overlap in the archaeological periods for samples used in this study.