Wetland sediments are valuable archives of environmental change but can be challenging to date. Terrestrial macrofossils are often sparse, resulting in radiocarbon (14C) dating of less desirable organic fractions. An alternative approach for capturing changes in atmospheric 14C is the use of terrestrial microfossils. We 14C date pollen microfossils from two Australian wetland sediment sequences and compare these to ages from other sediment fractions (n = 56). For the Holocene Lake Werri Berri record, pollen 14C ages are consistent with 14C ages on bulk sediment and humic acids (n = 14), whilst Stable Polycyclic Aromatic Carbon (SPAC) 14C ages (n = 4) are significantly younger. For Welsby Lagoon, pollen concentrate 14C ages (n = 21) provide a stratigraphically coherent sequence back to 50 ka BP. 14C ages from humic acid and >100 µm fractions (n = 13) are inconsistent, and often substantially younger than pollen ages. Our comparison of Bayesian age-depth models, developed in Oxcal, Bacon and Undatable, highlight the strengths and weaknesses of the different programs for straightforward and more complex chrono-stratigraphic records. All models display broad similarities but differences in modeled age-uncertainty, particularly when age constraints are sparse. Intensive dating of wetland sequences improves the identification of outliers and generation of robust age models, regardless of program used.

We present the first Bayesian 14C modeling based on AMS ages from stratified sediments representing continuous occupation across the Early Bronze III/IV interface in the Southern Levant. This new high-precision modeling incorporates 12 calibrated AMS ages from Khirbat Iskandar Area C using OxCal 4.4.4 and the IntCal 20 calibration curve to specify the EB III/IV transition at or slightly before 2500 cal BCE. Our results contribute to the continuing emergence of a high chronology for the Levantine Early Bronze Age, which shifts the end of EB III 200–300 years earlier than the traditional time frame and increases the length of EB IV to about 500 years. Data from Khirbat Iskandar also help direct greater attention to the importance of sedentary communities through EB IV, in contrast to the traditional emphasis on non-sedentary pastoral encampments and cemeteries. Modeling of AMS data from Khirbat Iskandar bolsters the ongoing revision of Early Bronze Age Levantine chronology and its growing interpretive independence from Egyptian history and contributes particularly to re-examination of the EB III/IV nexus in the Southern Levant.

Freshwater reservoir ages and a potential freshwater diet effect are examined for Manitoba (Canada), using paired samples of contemporaneous terrestrial, freshwater, and omnivore-diet species (Homo sapiens, Gavia sp.). The freshwater diet effect (n=4) varies from 220 to 370 14C years. The FRE (n=12) is temporally variable, with a median of 230 14C years and values up to 880 14C years (or more). Understanding the FRE is important for geologists who reconstruct the postglacial history of an area. It is also important for archaeologists who rely on 14C dating to develop cultural histories, as inhabitants of the Canadian boreal forest have relied upon freshwater resources as a part of their diet. An analysis of the δ13C on 93 freshwater mollusk samples from 11 species demonstrates significant variability, which highlights the difficulty in assigning an “assumed” fractionation correction.

The Meadowcroft Rockshelter in southwestern Pennsylvania is best known for its pre-Clovis occupation. Potentially important for later times is the recovery of maize macrobotanical remains from higher strata dating as early as the 4th century BC based on radiometric radiocarbon (14C) dates on wood charcoal. These remains have been considered to be potentially as old as the earliest microbotanical evidence for maize in Michigan, New York and Québec recovered from directly dated charred cooking residues adhering to pottery. The results of accelerator mass spectrometry (AMS) dating 17 samples from maize specimens from all Meadowcroft strata producing maize, indicate that the specimens originated from historical use of the shelter, most likely after AD 1800. These results further emphasize the need to obtain direct dates on maize macrobotanical remains recovered from early contexts prior to the development and common use of AMS dating.

Considered in isolation, the radiocarbon (14C) dates on short-lived plant remains from the Jean-Baptiste Lainé (formerly Mantle) site, Ontario, yield an ambiguous result: more or less similar probability around AD 1500 or alternatively around AD 1600. This village site, likely of no more than ca. 20–30 years total duration, illustrates the challenges of high-resolution dating across periods with a reversal/plateau in the 14C calibration curve. Another problem we identify is the tendency for dating probability for short-duration sites to sometimes be overly compressed as dating intensity increases under analysis with OxCal, and for probability to shift away from the real age range especially during reversal/plateau episodes. To address both issues additional constraints are necessary. While a tree-ring sequenced 14C “wiggle-match” is the best option where available, we investigate how, in the absence of such an option, use of the in-built age in wood-charcoal samples can be used to distinguish the likely correct date range. This approach can resolve ambiguities in dating, e.g., for shorter-duration Late Woodland village sites in northeastern North America, but also other short-duration cases corresponding with reversal/plateau episodes on the 14C calibration curve. We place the Jean-Baptiste Lainé site most likely in a range between ca. AD 1595–1626 (95.4% probability).

Current research indicates that full-fledged Neolithic societies emerged in the Southern Caucasus in the early sixth millennium BC, most likely through interaction with and/or the immigration of the Neolithic societies of Southwest Asia. However, the absence of late seventh millennium BC excavated sites has prevented us from being able to interpret the processes in relation to earlier indigenous foraging societies. The 2016–2019 excavations at Damjili Cave, west Azerbaijan, revealed a stratified cultural sequence of the key Mesolithic-to-Neolithic transition period for the first time. Its radiocarbon chronology identified a rather abrupt emergence of the Neolithic economy at around 6000 cal BC, at least in the study region, urging a reconsideration of the long-standing claim that some other form of earlier Neolithic society had existed before this. At the same time, the stratigraphic analysis of cultural remains revealed continuity in certain elements of tool manufacturing and use from the Mesolithic to the Neolithic. This complex situation shows the need for evaluating the degree to which indigenous foraging societies contributed to the Neolithization of the Southern Caucasus, rather than focusing merely on immigration models.

We present accelerator mass spectrometry radiocarbon (AMS 14C) dating results of the “Jochi Khan Mausoleum”—the proposed burial place of the oldest son of Gengghis Khan in Ulytau, Kazakhstan. The Ulytau region retains 34 burial complexes of Islamic tradition associated with the Golden Horde history (1221–1438 CE). However, there is no calendar-dated chronology of the medieval mausoleums in this region, which complicates their historical interpretation. Three 14C dates from construction timbers and burial of the Jochi Khan mausoleum are calibrated to 1220–1400 CE interval (95.4% range) with the mid-point at 1245 CE for the coffin, 1330 CE for the entry door, and 1350 CE for a masonry wall. The 14C-calibration suggests that the mausoleum was built about 100 years after the death of Jochi (1225 CE) and renovated at least once in the middle of the 14th century. Apparently, the wood for the coffin was harvested sometime in the interval 1220–1270 CE. The calendar ages of the coffin and the mausoleum are ca. 75 years apart. It is possible that the old coffin was placed into a newly constructed mausoleum. However, there is no historical evidence confirming this important re-burial of Jochi. The dating results challenge the attribution of the mausoleum to Jochi Khan. This study demonstrates that the age of the Islamic mausoleums in Ulytau can be successfully dated with 14C. While requiring further data assembly, this first 14C dataset can form the basis of the calendar chronology of the Golden Horde in Kazakhstan. Historical attribution of the mausoleums must be collaborated with the calendar chronology.

Caves containing perennial ice deposits make up a little-known, but emerging part of the cryosphere under increasing scrutiny from the scientific community. M-17, a sag-type ice cave opening at 1879 m asl in the Tolminski Migovec massif of the Julian Alps (NW Slovenia) contains a perennial underground ice deposit whose paleoclimate sensitivity is poorly understood and whose longevity under current climate change is at risk. The past mass balance of this cave is constrained using wood macro-remains embedded in ice. Accelerator mass spectrometry radiocarbon dating of 18 wood samples embedded in ice provides the largest currently available dataset for a subterranean ice deposit in the southern European Alps. The reconstructed chronostratigraphy reveals three main phases of likely positive ice balance around 900–1100 AD, 1200–1300 AD, and 1700–1800 AD, as well as a period of negative mass balance around 1300–1400 AD. The onset of cave glaciation is deemed to have occurred no later than about 900 AD, with evidence of overall positive ice mass balance during multi-decadal periods characterized by cooler-than-average summers and wetter-than-average springs. Conversely, negative mass balance is recorded during a period warmer-than-average summers and dry springs. The cave has experienced ice mass loss since its discovery in the 1980s.

The present paper is an announcement of first absolute age dating directly on fossilized bones and teeth of the Pleistocene mammalian fauna from the Manjra valley, District Latur, Maharashtra, India. The fossilized samples were measured using the AMS facility at Inter-University Accelerator Centre, New Delhi, India. The results gave the time frame of 21,423 BP to 24,335 BP that correspond close to and the threshold of LGM and sheds important light on the palaeoecology of the area that supported diverse megafaunal species in the Upper Manjra valley. These calendar dates not only have wider significance in terms of first ever approximate chronological frame for the Pleistocene fauna in Peninsular India but also offer methodological innovations especially when the adequate bioapatite is absent in the fossilized bones and teeth from the fossil record.

In this paper we evaluate the extent of freshwater reservoir effects (37 samples across 12 locations) and present new data from various archaeological sites in the Eurasian Steppe. Together with a summary of previous research on modern and archaeological samples, this provides the most up-to-date map of the freshwater reservoir offsets in the region. The data confirm previous observations highlighting that FREs are widespread but highly variable in the Eurasian Steppe in both modern and archaeological samples. Radiocarbon dates from organisms consuming aquatic sources, including humans, dogs, bears, aquatic birds and terrestrial herbivores (such as elk feeding on water plants), fish and aquatic mammals, as well as food crusts, could be misleading, but need to be assessed on a case-by-case basis.

Dates from the mammal fauna of Crystal Caverns, El Dorado County, California confirm that it is a Pleistocene deposit from the Last Glacial Maximum. Results indicate it is similar in age to other comparable California caves and has a high degree of time averaging.

New radiocarbon (14C) dates we obtained in our radiocarbon laboratory equipped with a liquid scintillation counter using BGO (Bi4Ge3012) tubes. The electronic stability of the counter gave a background below 0.2 cpm. Our 14C dates agree well with the interpretations done for the samples. Most of the results in these analyses were obtained on shell samples, charcoal samples, and tree leaves. Calibration of the dates with the appropriate software (Calib 7.0.4) allows better interpretation of the results and their importance in the studied regions. In this paper, we present 14C results from archaeological and environmental sites in Senegal, Mali, and Togo and report the results in our second laboratory date list.