Radiocarbon Dating Research Articles

Variability of lesions and lesion patterns in possible treponematosis cases: Insights from an archaeological site in Tomar, Portugal.

Objective: This study aims to describe various types of skeletal lesions and lesion patterns observed in five potential cases of treponematosis from the same archaeological site. Material and methods: The study examines five adult skeletons recovered from Santa Maria do Olival, Tomar, Portugal. Macroscopic observations were conducted on all remains, supplemented by relevant radiographic investigations. Results: The analyzed individuals exhibited diverse types of skeletal lesions and distinct patterns of lesion distribution. Radiocarbon dating of two of these skeletons locates them chronologically close to the beginning of the colonial period (15th century). Discussion: The findings indicate considerable variation in the lesions and lesion patterns associated with treponematosis, even within the same archaeological site. The radiocarbon data implies the presence of pre-Columbian treponemal disease or a rapid progression to the tertiary phase of the disease. This study represents the oldest cases of treponematosis in Portugal and the only one with more than one individual affected from the same archaeological site. Considering Portugal's prominent role in the European Age of Exploration, the study underscores the significance of pathogen exchanges between Europeans, South Americans, Africans, and Asians. Future investigations should reassess Iberian osteological collections from this time period, given the historical importance of Portugal and Spain in the intercontinental movements.

Chronostratigraphy of the Late Glacial Żabinko site (western Poland) and investigation of the dose rate variability

The Żabinko exposure (western Poland) reveals the classic fluvio-aeolian succession known from studies in the European Sand Belt. Previous chronostratigraphic studies were mainly based on uncalibrated radiocarbon dates from organic sediments and thermoluminescence dating. The picture visible from these studies indicated a number of discrepancies between these methods. The new research in this exposure was based on optically stimulated luminescence (OSL) dating and calibrated radiocarbon dates. The results obtained indicate a general discrepancy between the results achieved by these two methods. While the radiocarbon dates provide some meaningful picture and allow correlation with previous studies, the results of OSL dating do not allow for a chronological model of sedimentary processes. The OSL dates show large inversions of the results and are clearly younger than the other dating results. Detailed analysis of OSL measurements shows radioactive disequilibrium and variability linked to differential stratification of sediments, significantly impacting the assessment of environmental dose rates. We believe that this atypical variability is presumably the result of postdepositional processes, such as changes in groundwater levels, chemical weathering and radionuclide migration.

Methods for Dating the First Spanish American Lacquerwares: Seventeenth-Century Barniz de Pasto and Peribán Lacquer

This article examines the first Spanish American lacquerwares produced by Indigenous artisans in the seventeenth century, barniz de Pasto in Colombia and Peribán lacquer in Mexico, and discusses how the evolution of the decorative motifs, techniques, and forms of these lacquerwares can establish an initial dating chronology. Over the last thirty years, a sufficient number of examples of seventeenth-century Spanish American lacquerware have come to light that are datable, whether through provenance, historical references, or radiocarbon dating, and that make possible tentative chronologies for their production. The Hispanic Society of America in New York City holds at present the most significant collection of datable pieces of barniz de Pasto and Peribán lacquerware that now provide the key dates that can serve as the basis for establishing dating chronologies.

Latest Pleistocene-Holocene sedimentary evolution from sediment records of the Tam Giang-Cau Hai coastal lagoon system, central Vietnam

The latest Pleistocene-Holocene sedimentary evolution was reconstructed from two boreholes collected in the Tam Giang-Cau Hai coastal lagoon region of central Vietnam. This research was based on analyzing radiocarbon dating, grain size, sedimentary structure, petrological components, and diatom assemblages. Besides, some high-resolution seismic data from the lagoon water body were interpreted to estimate Holocene sediment thickness. Sedimentary records of two boreholes revealed various sedimentary facies under the sea-level change since the Last Glacial Maximum (LGM): Fluvial channel facies, fluvial-lagoonal transition facies, lagoon facies, lagoonal-to-fluvial facies, and flood plain facies. Radiocarbon dating indicated that the coastal lagoon system possibly initiated around 8.8–8.5 cal kyr BP, corresponding to the meltwater pulse 1 C when saltwater intruded into the lagoon system. The borehole-sediment data combined with the high-resolution seismic data shows the thickness of Holocene sediments is approximately 20–35 m in the lagoon region. The study also suggested that the sandy barrier complex along the coast between the lagoon system and the open sea has been likely built during the transgression since 10–8.8 cal kyr BP. Additionally, five ecological zones were identified based on diatom assemblages in borehole HK02 indicating variations in marine and fluvial influence in the coastal lagoon system during the past 8.8 kyr: Dia-HK02–1 indicates a low presence of diatoms, suggesting a weak marine influence in the coastal lagoon system; Dia-HK02–02 shows the strongest marine influence and stable ecological conditions in the coastal lagoon system; Dia-HK02–03 demonstrates a partial decrease in marine influence; Dia-HK02–4 shows an increasing fluvial influence; and Dia-HK02–5 developed under completely dominated fluvial conditions on land.

Firefly synchronicity and platform mound building by indigenous peoples of the Florida Peninsula, USA

ABSTRACT Although archaeologists often highlight the capacity of our field to identify broad-scale patterning in human societies, critiques of social evolution led many to focus on shorter-term, local histories. Drawing from a recent review of alternative models, we employ firefly synchronicity – the rhythmic coordination of flashing observed in some species of bioluminescent fireflies – as a model for understanding patterning in the timing of platform mound construction by Indigenous peoples of Tampa Bay, on the western coast of the Florida peninsula, USA. Bayesian modelling of radiocarbon dates and isotopic studies of oyster shells from three neighbouring sites reveals rhythmic coordination in the construction of platform mounds across the first millennium CE. We relate this patterning to interaction in seasonal and longer-term ritual cycles which may have facilitated collective management of zero-sum common property resources. Firefly synchronicity provides a useful model for identifying patterning in archaeological phenomena without much of the baggage of social evolution.

OSL and radiocarbon dating of core TBF-1 on the outer shelf of the East China Sea and implications for late Quaternary stratigraphic correlation

It is crucial to establish a robust chronology for understanding late Quaternary sedimentation processes and environment changes in response to sea-level fluctuation on shelves. The shelf of the East China Sea (ECS) is featured by huge terrigenous sediment input and striking land -sea interaction during the late Quaternary. However, there remains controversy in chronostratigraphic rebuilding of transgression and regression deposits during eustatic-glacial cycles, mainly due to a lack of reliable dating data. In this study, an extensive comparison of 17 optically stimulated luminescence (OSL) and 15 AMS 14C ages from core TBF-1 (upper 40 m) provides a constraint in chronostratigraphic reconstruction since Marine Isotope Stage (MIS) 5. OSL ages range from 9.5 ± 0.7 to 67.3 ± 4.8 ka at depths from 2.00 to 28.00 m, while 14C ages range from 6645 to 41435 cal a BP at depths from 0.02 to 17.52 m. Regression analysis demonstrates a high level of agreement between OSL and 14C ages, with r2 values of 0.91 and 0.90, respectively. For Holocene sediments (U1), both OSL and 14C methods are applicable in tidal sand ridges, however, it should be noted that 14C ages may exhibit a young bias of up to 3 ka. For pre-Holocene sediments (U6-U2), OSL ages are robust within saturation limitation of OSL signal (De up to ca. 166 Gy), cross-checked by feldspar post-IR IRSL (pIRIR) dating protocol. Nevertheless, the shell 14C ages (11620 and 10390 cal a BP at depths of 13.95–14.56 m) in Last Glacial Maximum (LGM) fluvial sediments of U2 are significantly underestimated, because of their susceptibility to recrystallization and overgrowth, resulting in carbon exchange with environment. While the peaty layer's14C age in deltaic deposition (17.50 m, U5) was determined to be 36420 cal a BP, coincided with OSL age of 39.6 ± 3.9 ka. The chronostratigraphy since MIS 5 for core TBF-1 exhibits a significant correlation with previously published cores SFK-1, DZQ4, and DH02, on the ECS outer shelf. Through the evaluation of those underestimated 14C ages and saturated OSL ages, we re-elucidated the primary sedimentary facies and their respective formation periods. This sedimentary stratigraphic illustration exhibits significant consistency with eustatic-glacial cycles. The renewed chronological framework for ECS shelf allows better correlation between the late Quaternary sedimentary evolution and the land-sea interaction on open shelves dominated by siliciclastic sedimentation.

Dolsko – Spodnje Škovce and a new insight into the settlement, chronology, ceramic style(s), and subsistence strategies of the Late Neolithic Sava group in Slovenia

Radiocarbon dates, analysis of ceramic finds, animal bones, fruits/seeds and wood (charcoal) from settlement features of the Sava group of the Lengyel Culture at the site of Dolsko – Spodnje Škovce in central Slovenia are presented and discussed in this paper. The aim of the study was to place the excavated material culture in its regional and supra-regional context in order to improve the understanding of Late Neolithic settlement features, chronology, pottery style(s) and subsistence strategies in settlements throughout the area of distribution of the Sava group. This is the first synthesis of archaeobotanical and archaeozoological data from the 5th millennium cal BC sites in Slovenia, including the evaluation and comparison of plant macro-remains and animal bones, and the first synthesis of data on technological and typological aspects of pottery production in the settlements obtained using the same analytical approach. Uncertainties regarding the chronology of different variations of a pottery style and subsistence strategies are emphasized.

Human response to the Younger Dryas along the southern North Sea basin, Northwest Europe

Currently in NW Europe little is known about the human response to the extensive cold reversal at the end of the Pleistocene, the Younger Dryas (ca. 12,850 till ca. 11,650 cal BP), mainly due to the poor chronological resolution of the archaeological sites belonging to the Ahrensburgian Culture. Here we present a series of 33 radiocarbon dates performed on the seminal cave site of Remouchamps, situated in the Belgian Meuse basin. Combined with a revision of the available radiocarbon evidence along the southern North Sea basin (Belgium, southern Netherlands, western Germany), it is suggested that the first half of the Younger Dryas, characterized as extremely cold and wet, faced a significant population reduction. Repopulation started around the middle of the Younger Dryas, from ca. 12,200 cal BP onward, probably in response to a slight climatic improvement leading to somewhat warmer summers. This might be considered a prelude to the subsequent population boost of the Early Holocene (Mesolithic).

Application of the CIEMAT/NIST method to 14C low-level measurements

Radiocarbon dating of samples from benzene synthesis by low-level Liquid Scintillation Counting (LSC) method requires the availability of 14C standards in benzene, which are difficult to obtain, or the use of an absolute measurement which is out of reach for most analytical laboratories. This paper describes how the CIEMAT/NIST method can help to solve this issue and presents the measurements of low activity concentrations performed in the LRI-D using two different benzene base scintillator cocktails.

Effect of plant roots on the radiocarbon age of loess deposits in arid central Asia

Radiocarbon and OSL dating are the two main approaches used to date aeolian deposits in arid central Asia (ACA). Previous results showed that, compared with OSL dating, the 14C ages of loess deposits in ACA are underestimated when the loess age is beyond ∼25 ka. However, the cause of this radiocarbon age underestimation has not been adequately addressed. In this study, we measured the 14C ages of different dating materials, including pyrolysis volatile (Py-V), pyrolysis residue (Py-R), humin, and total organic carbon fractions from two loess sections in ACA (the Hoalin section in the western Pamir Mountains, and the TLD16 section in the northern Tianshan Mountains). The results show that different dating material yielded different 14C ages for all the loess samples, and all the radiocarbon ages obtained are younger than their corresponding OSL ages. Based on these results, together with a regional comparison of 78 14C ages from ACA with their corresponding OSL ages, we propose that the 14C age underestimation is mainly due to the contamination by the deep penetration of the extended root systems of the plants that grow in arid areas, whereas this effect is less significant in the summer monsoon–dominated Chinese Loess Plateau.

New sites and challenges in prehistoric archaeology of Uruguay: recurrent occupations in caves, rockshelters and earthen mounds

AbstractSystematic investigation of caves and rockshelters in Uruguay is revealing the archaeological importance of these sites and their association with earthen mounds. Multiple periods of human occupation at Tamanduá rockshelter are revealed through stratigraphic analysis, and radiocarbon dates suggest recurrent occupation from the Early Holocene up to the historic period.

Radiocarbon dating of lipids preserved in pottery vessels: guidelines for best-practice in compound-specific 14C analyses

Radiocarbon dating of lipids preserved in pottery vessels: guidelines for best-practice in compound-specific ¹⁴C analyses

Do counts of radiocarbon-dated archaeological sites reflect human population density? A preliminary empirical validation examining spatial variation across late Holocene California

AbstractResearchers increasingly rely on aggregations of radiocarbon dates from archaeological sites as proxies for past human populations. This approach has been critiqued on several grounds, including the assumptions that material is deposited, preserved, and sampled in proportion to past population size. However, various attempts to quantitatively assess the approach suggest there may be some validity in assuming date counts reflect relative population size. To add to this conversation, here we conduct a preliminary analysis coupling estimates of ethnographic population density with late Holocene radiocarbon dates across all counties in California. Results show that counts of late Holocene radiocarbon-dated archaeological sites increase significantly as a function of ethnographic population density. This trend is robust across varying sampling windows over the last 5000 BP. Though the majority of variation in dated-site counts remains unexplained by population density. Outliers reveal how departures from the central trend may be influenced by regional differences in research traditions, development-driven contract work, organic preservation, and landscape taphonomy. Overall, this exercise provides some support for the “dates-as-data” approach and offers insights into the conditions where the underlying assumptions may or may not hold.

Constraining Mean Landslide Occurrence Rates for Non‐Temporal Landslide Inventories Using High‐Resolution Elevation Data

AbstractConstraining landslide occurrence rates can help to generate landslide hazard models that predict the spatial and temporal occurrence of landslides. However, most landslide inventories do not include any temporal data due to the difficulties of dating landslide deposits. Here we introduce a method for estimating the mean landslide occurrence rate of deep‐seated rotational and translational slides derived solely from high‐resolution (≤3 m) elevation data and globally available estimates of the diffusion coefficient for sediment flux. The method applies a linear diffusion model to the roughest landslide deposits until they reach a representative non‐landslide roughness distribution. This estimates the time for a landslide deposit to be unrecognizable in high‐resolution digital elevation data, which we term the mean lifetime of the landslide. Using the mean lifetime and number of landslides within an area of interest, we can estimate the mean occurrence rate of landslides over that domain. We validate this approach using a comprehensive temporal inventory of landslides in western Oregon created using age‐roughness curves that are calibrated with high‐resolution elevation data and radiocarbon data. We find good agreement between our diffusion method and the existing age‐roughness‐derived estimates, producing mean lifetimes of 4500 and 5200 years (4% difference), respectively. Hazard maps produced using the two methodologies generally agree, with the maximum differences in landslide probability reaching 0.1. Due to the relative abundance of high‐resolution elevation data compared with age‐dated landslides, our method could help constrain landslide occurrence rates in areas previously considered unfeasible.

Chronological considerations for the use of the Late Roman–Migration period Cemetery at Plinkaigalis, Lithuania

AbstractThis study presents new (n=32) and previously published (n=35) human bone 14C AMS dates from 54 individuals interred in 50 burials in the Plinkaigalis cemetery (3rd–7th century AD, Lithuania). The aim of this study is to establish duration of use and identify temporal subgroups within the cemetery. Individuals in group burials were assessed for temporal agreement across individuals and the dates for individuals with multiple dates were combined using OxCal. The Sum command, Interval command, and two Bayesian models (overlapping and abutting periods of use) were used to approximate the use of the site over time and evaluate the chronology of dated burials. An IDW (inverse distance weighted) model was employed to visualize median radiocarbon dates across the cemetery for comparison to earlier IDW interpolations of time at Plinkaigalis. While the two models cannot be distinguished at this time, it can be determined that the site was likely in continuous use from 200–600 cal AD (Sum), 230–560 cal AD (Model 1), 220–550 cal AD (Model 2), or cal 283–508 AD (IDW). The area of the cemetery associated with earliest use shifted east when the IDW model was compared to original data. There was also poor agreement in some group burials and burials with multiple dates. The models generally agree on assignment of burials to phases, but disparate phase assignment was noted across the IDW and Bayesian models. Temporal subgroups cannot be confidently reclassified beyond early/later periods of use based on these models without additional sampling and refinement of the IDW modeling method.

Investigating Holocene relative sea-level changes and coastal dynamics in the mid-Tyrrhenian coast, Italy: An interdisciplinary study

Understanding millennial changes in relative sea level (RSL) and coastal responses in stable regions is crucial for deciphering the intricate relationship between natural dynamics and human adaptation. This interdisciplinary study explores the interplay between mid-to-Late Holocene sea-level fluctuations and tectonic along the mid-Tyrrhenian coast.The study area, located between the Fondi and Garigliano coastal plains, held great significance in ancient times. In particular, the strategic role of Formia, a monitoring point for the Tyrrhenian Sea, made this city one of the most important commercial hub during Roman occupation, leading to a significant urbanization of the coastal stretch testified by well-preserved remains nowadays scattered along the submerged or semi-submerged coastal sectors.This study reconstructs the mid-to-Late Holocene morpho-evolution and RSL changes in the study area by creating a geodatabase made of 52 sea-level markers (SLMs) derived from direct geoarchaeological measurements, stratigraphic and palaeoecological interpretations of new borehole data, and previously published stratigraphic data. Specifically, the radiocarbon dating of three peat samples provided new data ranging between 7.62 ± 47 and 1.00 ± 51 ka BP on the sea level history in the area. Based on our dataset, between 9.0 and 8.0 ka BP, the sea level rose from −19 m to −6.5 m at a rate of about 15.6 mm/y, slowing to 0.8 mm/y afterwards, stabilizing at its current position. Results suggest that during the 1st century BC, local sea level was no higher than −0.55 ± 0.29 m.The collected RSL data support the hypothesis of tectonic stability of this sector during the last 2.0 ka, testified by the position of the SLMs in accordance with the glacio-hydro-isostatic adjustment (GIA) models and supported by the determination of average vertical ground movement rates of −0.017 ± 0.23 mm/y.Finally, in terms of coastal changes the overlay between new data from geoarchaeological surveys, reinterpretation of previously-published stratigraphic data, and geomorphological analysis allowed us to deduce a general coastal progradation trend in the historical time for both low-lying and rocky sectors, due to natural and anthropogenic forcing factors.

Ancient DNA sheds light on the funerary practices of late Neolithic collective burial in southern France.

The Aven de la Boucle (Corconne, Gard, southern France) is a karst shaft used as a collective burial between 3600 and 2800 cal BCE. The site encompasses the skeletal remains of approximately 75 individuals comprising a large majority of adult individuals, represented by scattered and commingled remains. To date, few studies have explored the potential of ancient DNA to tackle the documentation of Neolithic collective burials, and the funerary selection rules within such structures remain largely debated. In this study, we combine genomic analysis of 37 individuals with archaeo-anthropological data and Bayesian modelling of radiocarbon dates. Through this multidisciplinary approach, we aim to characterize the identity of the deceased and their relationships, as well as untangle the genetic diversity and funerary dynamics of this community. Genomic results identify 76% of male Neolithic individuals, suggesting a marked sex-biased selection. Available data emphasize the importance of biological relatedness and a male-mediated transmission of social status, as the affiliation to a specific male-lineage appears as a preponderant selection factor. The genomic results argue in favour of 'continuous' deposits between 3600 and 2800 BCE, carried out by the same community, despite cultural changes reflected by the ceramic material.

Interpretation and implications of high-resolution hydroclimatic records of the past 7,000 years based on Gaho paleolake sediments in South Korea

In this study, we investigated the past hydroclimate and its controlling factors over East Asia by reconstructing hydroclimate variability during the middle-to-late Holocene using rainfall-driven sedimentary features in the Gaho paleolake, Hapcheon County on the southern Korean Peninsula. Based on radiocarbon dates, median grain sizes, and elemental ratios of strontium (Sr), titanium (Ti), and zirconium (Zr) measured by high-resolution X-ray fluorescence core scanning, we tested potential indicators of past heavy rainfall. During the past 7000 years, temporal changes in median grain size and elemental ratios (Sr/Ti and Zr/Ti) were found to be similar to those in the Asian monsoonal precipitation index and sea surface temperature (SST) in the western North Pacific region, suggesting that periods with increased elemental ratios may have been influenced by intensified regional rainfall events and higher SSTs. During the past 2000 years, time series of Sr/Ti and Zr/Ti ratios in the paleolake sediments appeared to covary with a megadrought period (AD 1593–1698; 357-252 cal BP), flooding events in the 1500s, and the collapse of ancient nations in Korea and other parts of East Asia. This similarity between sedimentary records and historical events suggests considerable potential for the dating of elemental ratios in lake sediments as high-resolution analogs of past hydrological events to support historical records.

Past Fire and Vegetation Change in the Hyperdiverse Forests of the Ecuadorian Amazon.

The Ecuadorian Amazon holds more biodiversity than most other places on Earth. Palms are a particularly dominant component of the vegetation; however, it remains unknown to what degree the pattern has persisted through time. Here, we investigate the persistence of palm dominance through time and the degree to which past human activities (e.g., fire, cultivation, and forest opening) have affected changes in palm abundances across five regions of the Ecuadorian Amazon. We analyzed soil cores (40-80 cm depth) from each region for charcoal (evidence of past fire) and phytoliths (evidence of past vegetation change). The timings of fires (based on 14C radiocarbon dates), the occurrence, recurrence, and number of fires (based on charcoal presence and abundance in samples), and the amount of change in palm abundances (based on phytoliths) varied within and between the studied regions. The charcoal and phytolith results indicate the presence of low levels of past human activity at all sites. Our results show that patterns of modern palm hyperdominance found in Amazonian forests have not been persistent through time, and that even low levels of past human activities can affect palm abundance.

MIS 3 innovative behavior and highland occupation during a stable wet episode in the Lake Tana paleoclimate record, Ethiopia

Securely dated archaeological sites from key regions and periods are critical for understanding early modern human adaptive responses to past environmental change. Here, we report new radiocarbon dates of > 42,000 cal years BP for an intensive human occupation of Gorgora rockshelter in the Ethiopian Highlands. We also document the development of innovative technologies and symbolic behaviors starting around this time. The evidenced occupation and behavioral patterns coincide with the onset and persistence of a stable wet phase in the geographically proximate high-resolution core record of Lake Tana. Range expansion into montane habitats and the subsequent development of innovative technologies and behaviors are consistent with population dispersal waves within Africa and beyond during wetter phases ~ 60–40 thousand years ago (ka).