A03_01

The Meryt Model: towards a new chronometric model for the Egyptian Old Kingdom

Quiles A¹, Aubourg E², Beck L³, Ciavatti A¹, Delqué-Kolic E³, Ferrant M^1,4, Muller S⁵, Salati P⁶

¹Institut français d'archéologie orientale (IFAO), Cairo, Egypt, ²Laboratoire AstroParticule et Cosmologie, Paris, France, ³Laboratoire de Mesure du Carbone 14/LSCE, Gif-Sur-Yvette, France, ⁴Laboratoire De la Molécule aux Nano-objets : Réactivité, Interactions et Spectroscopies, Sorbonne Université, Paris, France, ⁵Institut de Systématique, Évolution, Biodiversité (ISYEB), , France, ⁶Laboratoire d'Annecy-le-Vieux de Physique Théorique, Université de Savoie Mont Blanc & CNRS, Annecy, France

The MERYT project aims to build an accurate, high-resolution and multi-technical chronological model for the Egyptian Old Kingdom (~2900-2200 BCE), through an integrated approach bringing together all the analytical criteria of Egyptology, Archaeology and Archaeometry. It addresses two major issues: to develop a definitive chronological framework of the Old Kingdom, reign by reign, by building a statistical model reconciling Egyptological and analytical data; to explore the IntCal calibration curve considering the specific environmental conditions in Egypt, in particular due to the Nile flooding.

In that respect, through a historical approach, we have re-evaluated textual sources owing chronometric evidence to re-evaluate all reign certificates and assess their reliability to restore an updated succession of kings’ list and the most accurate estimates of their reigns’ duration. Through an archaeometric approach, we have carried out ¹⁴C dating’s series almost all on samples collected directly on on-going archaeological excavations in Egypt, which age is clearly associated with a single reign. Specifical improvements have been performed on textile samples’ analysis protocol to ensure their dating when contaminated by funeral chemicals, and accurately model their result. We also have investigated possible regional offset to IntCal within the Egyptian land due to seasonal effect, by analyzing botanical samples from the Paris Herbarium. The whole is finally confronted together in a statistical Bayesian model whose formalism is fully developed for this project.

This talk will present first results of the Meryt Model and be completed by open perspectives, bringing new insights on the start of the Egyptian state.

A03_03

Dating the stylistic periods of Australian Aboriginal Rock Art

Finch D¹, Gleadow A¹, Hergt J¹, Heaney P³, Green H¹, Myers C⁴, Levchenko V²

¹University Of Melbourne, Parkville, Australia, ²Australian Nuclear Science and Technology Organisation, Sydney, Australia, ³Rock Art Australia, Melbourne, Australia, ⁴Dunkeld Pastoral Company, Dunkeld, Australia

The Kimberley region in north-western Australia is home to one of the world’s richest rock art provinces. Field observations at almost 4000 rock art sites over the last 40 years led researchers to define five main styles of painted rock art, some of which were thought to date back to the Pleistocene. While there is general agreement regarding the relative sequence of stylistic phases, there has been very little geochronological evidence to support the proposed sequence or its antiquity. Only some of the rock art from the most recent period contains material that is suitable for radiometric dating. All recent attempts to date the art, therefore, focus on determining the age of material found overlying or underlying paintings to establish minimum or maximum age constraints for individual motifs.

Our research uses radiocarbon dating of mud wasp nests found in contact with rock art to constrain the age of individual paintings. Results to date have established that the stylistic sequence spans at least 17,000 years. Age constraints for multiple motifs, of the same stylistic period, are used to estimate when that particular style of painting was employed. Statistical analysis of the results then explores the level of uncertainty associated with the currently available data and is used to estimate what additional dating results are required to achieve higher levels of confidence.

A03_04

Wiggle-match dating on display: minimally destructive analysis of early American museum objects

Hadden C¹, Napora K²

¹Center For Applied Isotope Studies, Athens, United States, ²William S. Webb Museum of Anthropology, Lexington, United States

Wiggle-match dating of tree-ring sequences is particularly promising for achieving high-resolution dating across periods with reversals and plateaus in the calibration curve, such as the entire post-Columbian history of North America. Here we describe the process of wiggle-match dating two museum objects of significance to 18th–19th century United States history: (1) a cypress dugout logboat exhibiting a unique combination of European and Native American design elements; and (2) a tulippoplar wood trough utilized by an enslaved workforce in the production of saltpeter. Tree rings were counted and sampled for dating from exposed, rough cross-sections in the wood, with no or minimal surface preparation, to preserve these fragile objects. Both contained relatively long tree-ring sequences (>220 rings). Single-year samples were collected from the innermost ring and at approximately 10-year intervals from the outer ~50 rings, with practically no visible damage to the objects. The samples were radiocarbon dated by AMS, and the dates were modeled in OxCal using the Sequence and Interval functions to account for uncertainty in ring counts, rather than the D_Sequence and Gap functions that are more commonly used in wiggle-match dating. By this method, the outermost tree ring of the logboat’s hull dated to 1766–1796 cal AD, and the trough to 1778–1804 cal AD (95% highest posterior density ranges). Dendrochronological dating supports the radiocarbon wiggle-match dating for both objects. This study demonstrates that high-precision dating can be achieved for 18th–19th century objects through wiggle-match dating, with minimal damage to the objects of study.

A03_05

Sampling ritual complexity: the case study of the megalithic Panoría site (Granada, Spain).

Milesi García L¹, Aranda Jiménez G¹, Díaz-Zorita Bonilla M², Sánchez Romero M¹, Vilchez Suárez M¹, Robles Carrasco S¹

¹Universidad De Granada, Granada, Spain, ²Universität Tübingen, Tübingen, Germany

Late prehistoric south-eastern Iberia is considered a privileged setting for studying the development of important Megalithic sites as well as the emergence of complex societies during the Copper and Bronze Ages. Through several chronological projects and diverse sampling strategies, our research has increased the number of radiocarbon dates in more than 250, covering 12 sites from the coastline to the inland of the region.

We present here the analysis of one of them as it is an excellent case study to demonstrate how chronologically oriented fieldwork planning, remain recovery processes and anthropological study of potential radiocarbon dating samples have a critical effect on results and accurate chronologies, especially in contexts where depositions are highly commingled.

The megalithic cemetery of Panoría (Granada, Spain), with nine excavated tombs, counts on a well-known stratigraphy and seventy-three radiocarbon dates, also analysed within a Bayesian framework. Results allow us now to explore the tempo of ritual activities throughout time for each tomb. Also, they lead us to some refined chronological conclusions for the site where: 1) the second half of the 4th millennium BC was an intensive and brief period of funerary depositions in all tombs; 2) most of the dolmens were reused in the 25th and 21st centuries cal BC during even shorter periods; 3) the cemetery was still recognised as a ritual place and used in the Late Antiquity.

A03_07

Developing a chronology for pre-Columbian Amazonia through the HERCA project

Becerra-Valdivia L¹, Bronk Ramsey C¹

¹Oxford Radiocarbon Acceleration Unit, Oxford, United Kingdom

Pre-Columbian (pre CE 1492) Amazonia is typically believed to have been sparsely inhabited by hunter-gatherers largely constrained by their environment. Increased research, however, shows evidence for sedentarism, stratification, and a long history of landscape manipulation. This includes the construction of monumental structures in large (>100 ha), urban settlements (1); canal and causeway networks (2); and plant domestication dating to the early/mid Holocene (3). Aimed at better understanding these societies and their relationship with the environment, ‘Human-Environment Relationships in pre-Columbian Amazonia’ (HERCA) is an interdisciplinary project that integrates archaeological and paleoecological data through the lens of time. Chronometric research, based at the Oxford Radiocarbon Accelerator Unit, includes the creation of highly resolved human-occupation and paleoenvironmental sequences, the integration of chronometric and contextual information through Bayesian modelling, and data management. Here we present current research results and the newly built HERCA Database. The latter, currently holding >500 unique records, allows for the storage/management of multi-proxy data and associated materials. Investigations to be discussed include the development of key archaeological and paleoecological chronologies in the region, and the commencement of monumental construction in Brazil and Bolivia.

1.           Prümers et al., Lidar reveals pre-Hispanic low-density urbanism in the Bolivian Amazon. Nature (2022). doi:10.1038/s41586-022-04780-4.

2.           Lombardo & Prümers, Pre-Columbian human occupation patterns in the eastern plains of the Llanos de Moxos, Bolivian Amazonia. J. Archaeol. Sci. 37, 1875–1885 (2010).

3.           Watling, et al., Direct archaeological evidence for Southwestern Amazonia as an early plant domestication and food production centre. PLoS One 13, e0199868 (2018).

A03_08

Pre-Columbian occupation chronology of southern coast of Nayarit, Mexico.

Solis C²

¹Dirección de Salvamento Arqueológico, INAH, Mexico City, Mexico, ²Instituto de Física, Universidad Nacional Autónoma de México, Mexico City, México, ³Facultad de Ciencias, Universidad Nacional Autónoma de México., Mexico City, México, ⁴Instituto Superior De Tecnologías y Ciencias Aplicadas, Universidad de La Habana , La Habana, Cuba

The area of western Mexico has been little studied, mainly due to difficulties of access. Chronicles from the first half of the 16th century describe fertile plains and densely populated wetlands. The Directorate of Archaeological Salvage of INAH, conducts archaeological research when it comes to modern works, and undergoes studies of previously unknown Pre-Columbian occupation sites.  The present work deals with the study of the material recovered from two sites in Costa Canuva (Pacific Ocean), in the South of the state of Nayarit: Becerros (site mainly used for burials) and Naranjos (used for residence and burials). The majority of the ¹⁴C dating of materials recovered at Becerros provided a chronological framework of absolute dates for the occupation of the site from 217 cal A.D. to 1025 cal A.D., corroborating the ceramic studies in the sense that human settlement activities date from the Tombs of Tyre Tradition (300 B.C. to 600 A.D.) to the Early Postclassic (900 to 1100 A.D.). The dated materials from the Naranjos site, yielded ages correlated with the Classic period (500-750 AD), however, material dating from 1670-1780 was also found, associated with glazed ceramics, a technique introduced by the Spaniards. This indicates that rituals in these regions may have continued for another 100 years after the conquest of the altiplano. Finally, dates of charcoal and associated shell samples from the Naranjos Unit were compared to complement the dating of the occupation of the site.

Acknowledgments: Arcadio Huerta and Sergio Martínez for technical assistance, CONACyT 2022.

A03_09

The dating of dolomitic mortars with uncertain chronology from Müstair Monastery: sample characterization and combined interpretation of results

Caroselli M¹, Hajdas I², Cassitti P³

¹SUPSI, Mendrisio, Switzerland, ²ETH, Ion Beam Physics Lab. , Zurich, Switzerland, ³Foundation Pro-Kloster St. Johann , Müstair, Switzerland

To obtain scientific data regarding the chronology of archaeological structures, lime mortar radiocarbon dating has often demonstrated to be a decisive method. However, it is well known that certain chemical-mineralogical characteristics of the mortars can greatly influence the results. Among other issues, the dating of magnesian mortars can be particularly difficult because of the combined slaking, setting and hardening reactions of the calcium and magnesium phases, typical of these mortars. The formation of numerous mineralogical phases depending on reaction conditions adds further complexity to the dating method, which deserves to be studied with further detail. During the project "Mortar technology and construction history of Müstair Monastery" thanks to the presence of numerous mortar fragments belonging to different construction phases, the first experiments in this regard had yielded encouraging results. An additional 5 samples from buildings with controversial chronology, thought to belong approximately to the 9th, 12th and 15th centuries, were selected, prepared and radiocarbon dated. The data obtained were discussed by integrating preliminary petrographic and chemical characterization analyses of the mortars with archaeological information and excavation records. The results provided a better understanding of the potential and limitations of dating dolomitic mortars coming from archaeological context.

A03_10

Characterization and selection of mortar samples for radiocarbon dating in the framework of MODIS2 intercomparison: results of the Italian laboratories

Maspero F¹, Galli A¹, Panzeri L¹, Martini M¹, Ricci G², Secco M³, Artioli G², Fedi M⁴, Barone S⁴, Liccioli L⁴, Marzaioli F⁵, Passariello I⁵, Terrasi F⁵

¹Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca (Italy) and CUDAM (Centro Universitario Datazioni e Archeometria Milano-Bicocca), Milano, Italy, ²Dipartimento di Geoscienze, Università degli Studi di Padova, Padova, Italy, ³Dipartimento di Beni Culturali, Università degli Studi di Padova, Padova, Italy, ⁴INFN, Sezione di Firenze , Firenze, Italy, ⁵Dipartimento di Matematica e Fisica, Università degli Studi della Campania Luigi Vanvitelli, Napoli, Italy

Since several decades, many efforts have been devoted to improve the accuracy of mortar radiocarbon dating and to assess the reliability of the results in relation with the typology of the examined specimen. Several assumptions for the application of the method are in many cases not fulfilled, among which: a) complete primary limestone dissociation during calcination; b) efficient separation of geogenic carbon contained in calcareous aggregates; c) short carbonation time; d) absence of dissolved CO₂ in running water exchanging carbonate ions. Many laboratories all over the world have proposed different methods to select suitable fractions of mortar particles.

The first intercomparison attempt, involving eight international laboratories, was made in 2016 to reach a common characterization and pretreatment method of mortars to optimize the radiocarbon dating results. Following this first step, a new intercomparison experiment was proposed and set up in 2018 during the Mortar Dating International Meeting (Bordeaux, FR). A new set of three mortar samples was chosen, taking care about the selection of standardized materials (homogeneous, with defined mineral types, devoid of exogenous inclusions, of known ages).

This work describes the results of the Italian laboratories involved in the intercomparison. The samples were characterized, selected and dated depending on each laboratory strategy. The data are encouraging and shed light on future steps to be taken to standardize a method for prior characterization and selection of samples suitable for radiocarbon dating.

A03_11

Radiocarbon and OSL dating of Caesar’s Forum in Rome

Olsen J¹, Schrøder T¹, Kinnard T, Kristiansen S, Kindbjerg J, Presicce  C, Vitti M, Raja R

¹Aarhus University, Aarhus, Denmark

Here we present radiocarbon dating of 122 animal bone samples and OSL profiling to accurately date the stratigraphy of Caesar’s Forum in Rome. The stratigraphy covered the period from the Recent Bronze Age (13th Century BCE)   to the 1932s. Stable isotope analysis on the bone samples provided data for a discussion of dietary baselines. The radiocarbon dates fell within the approximate range 400-3000 ¹⁴C years BP, as expected from the stratigraphy. Three Bayesian chronological models were made by assuming a sequence of overlying stratigraphic units, while the models used outlier modelling that allowed a sample to be redeposited in its associated stratigraphic unit. The OSL profiling aided the Bayesian modelling and sample selection by identifying phases with a high risk of re-deposition. Bayesian modelling was conducted on two excavation areas (A and C). In area A, the chronological model showed activity in late antiquity and early medieval era, from the 3rd century CE to the 8th century CE. In area C, the first chronology showed activity in the archaic era to antiquity, from 8th century BCE to the 4th century CE. In area C, the second chronology told of activity from the medieval era to the renaissance, 10th century CE to the 16th century CE. In area C’s first chronology an interesting aspect was to look for the end of the archaic era and the floor of Caesar’s forum. In area C’s second model an interesting aspect was stratigraphic units with many outliers, which were signs of redisposition of soil.

A03_12

Effect Of Lime Production And Processing Methods On The Presence Of Geogenic Carbon In Historical Mortars

Válek J¹, Kozlovcev P¹, Fialová A¹, Kotková K¹, Frankeová D¹, Světlík I², Pachnerová Brabcová K²

¹Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences, Prague, Czech Republic, ²Nuclear Physics Institute of the Czech Academy of Sciences, Prague, Czech Republic

The presence of geogenic carbon makes the radiocarbon dating of historical mortars a challenging task. Part of the geogenic carbon in mortars is commonly present due to the production and processing of lime binder. Lime burnt with wood in a traditional kiln was assessed for the presence of residual CO₂. Quicklime samples were taken from various locations in the kiln and thermal analysis was used to quantify the CO₂ residual levels. The quicklime obtained was slaked in excess of water and the presence of unburnt particles was investigated after sedimentation of the lime putty at three depth levels: top, middle and bottom. An optical microscope with Cathode Luminescence probe was used to qualitatively evaluate the presence of unburnt particles. In addition, the three putty specimens per lime sample were left to carbonate at laboratory conditions. After carbonation, the content of stable isotopes ¹³C and ¹⁸O was determined. This experimental procedure allows for description and estimation of the presence of geogenic carbon in quicklime produced in a wood-fired single batch kilns. It also shows the effectiveness of sedimentation treatment to reduce under-burnt lime particles. The comparative study of stable isotopes studies the possibility of evaluating a carbonated lime binder prior to its ¹⁴C analysis. The results suggest that the historical treatment of lime to produce a fine binder could potentially lead to mortar samples that are more suitable for radiocarbon dating than mortars produced directly from quicklime or dry slaked lime to hydrate.

A03_14

Alpine archaeology and radiocarbon analysis: a match made in heaven!

Leuzinger U¹, Hajdas I², Guidobaldi G², Wyss K², Imhof W³

¹Amt für Archäologie Thurgau, Frauenfeld, Switzerland, ²Ion beam Physics ETH Zurich, Zurich, Switzerland, ³Staatsarchiv Schwyz, Schwyz, Switzerland

A team of researchers have been examining rock shelters and ruins in the municipality of Muotathal (Canton Schwyz, Switzerland) at the behest of the State Archive of Canton Schwyz since 2006. The study region is located in the pre-Alps and extends to altitudes of between 600 and 2400 m a.s.l. Many of the small archaeological test excavations yield charcoal fragments and faunal remains. Radiocarbon analyses carried out on the organic remains allow us to assess the potential of any newly discovered site. At this stage, the period covered by the finds stretches from cave bears dated to around 36,000 BP to Mesolithic hunters’ camps from around 9000 BP, to Neolithic, Bronze Age, Iron Age and Roman-period finds from between 5000 and 2000 BP as well as numerous medieval and post-medieval deserted Alpine huts and pens.

The Berglibalm and Flözerbändli rock shelters discovered in 2015 and 2020 respectively are of international significance. They yielded layers containing animal bones, stone artefacts and botanical remains from the Epipalaeolithic but mostly from the Early Mesolithic. While the microliths made of flint can be typologically dated to the Mesolithic, radiocarbon analysis of the hearths allows us to date the finds even more precisely.

One of the more remarkable objects discovered is a decorated piece of red deer antler from Muotathal-Flözerbändli, which was radiocarbon dated to the Azilian (ETH-109223, 10354±31 BP) at the Laboratory of Ion Beam Physics at ETH Zurich. It is the only decorated antler artefact from that period found in Switzerland so far.

A03_15

When the boundaries do not hold: alternative interpretation for archaeological transition, cultural changes and climate

Boaretto E¹

¹D-REAMS Radiocarbon Lab, Weizmann Institute of Science, Rehovot, Israel

Chronology is at the base of archaeological and paleoclimate research and it is fundamental for synchronization of different events. The time frames need to be as precise as possible and to be determined independently from other stratigraphic and cultural sequences. The assumption of time contemporaneous boundaries between archaeological periods is often used for synchronization between sites, and to correlate the cultural periods without  radiocarbon dating. I have documented several examples of misinterpretation of such correlations in the absence of radiocarbon dating, and in some cases sites are just a few kilometers apart and in the same environmental niche. Furthermore, when the assumption that “similar cultural remains reflect similar time periods” is applied, and when time boundaries contradict radiocarbon dates, the latter are often regarded as the source of the problem. The underlying inconsistencies are often revealed in the radiocarbon modelling. The study of the archaeological record and its stratigraphy both at the macroscopic level and most important at the microscopic level is of fundamental importance. Examples will be presented along the 50000 years of ¹⁴C range, such as the association of the Younger Dryas and the transition to the earliest settlements, the integration or replacement of the Byzantine culture by the Islamic conquest in the peripheral region of the Negev, and the decline of the City States in the Levant.

A03_16

A radiocarbon chronology for Iron Age Jerusalem: Hallstatt Plateau, known age events, and regional offsets

Regev J¹, Uziel J², Gadot Y³, Ben-Ami D², Mintz E¹, Regev L¹, Boaretto E¹

¹Weizmann Institute of Science, Rehovot, Israel, ²Israel Antiquities Authority, Jerusalem, Israel, ³Tel Aviv University, Tel Aviv, Israel

The Iron Age in Jerusalem, covering the 13th to 6th centuries BC, is one of the most excavated, studied, and debated topics in the southern Levant archaeology. Much of the interest has been sparked and fuelled by the ancient texts relating to Jerusalem and, in particular, the biblical narrative, also attracting wide public attention.

However, these events were never anchored with an absolute chronology based on independent radiocarbon dates. Only recently, we have integrated the microarchaeology-based radiocarbon sampling to Jerusalem, to build an absolute and accurate chronology. 

We have studied three areas in the “City of David,“ covering the entire Iron Age period. One of the major challenges for chronology was the Halstatt plateau. Samples dating between the 8th-6th centuries BC all give similar calibrated ranges coinciding with the later part of the Judean kingdom. We exposed superimposed pottery-rich floors, from which in-situ contexts were characterized and dated. These measurements allowed for “short-lived wiggle matching” through stratigraphic modeling, consequently providing a high precision dating even during the Hallstatt plateau.

We high-precision dated a context relating to the earthquake mentioned in the book of Amos and several contexts from the time of destruction by the Babylonians in 586 BC. The stratigraphic sequences and events, considered historically well established, provided an opportunity to assess the existence of regional differences in past ¹⁴C concentrations. The dates measured from several structures occupied till the Iron IIC showed a discrepancy between the meager quantity of early pottery types vs. the significant presence of early dates.

A03_17

Untangling chronology at Tel Gezer: connecting radiocarbon, archaeology, Egyptology and the Bible

Webster L¹, Wolff S², Ortiz S³,  Tsuk T⁴, Warner D⁵,  Parker J⁵, Yannai E⁶, Dee M⁷, Hua Q⁸,  Jacobsen G⁸, Höflmayer F¹

¹Austrian Academy Of Sciences, Vienna, Austria, ²W. F. Albright Institute for Archaeological Research, Jerusalem, Israel, ³Lipscomb University, Nashville, USA, ⁴Israel Nature and Parks Authority, Jerusalem, Israel, ⁵New Orleans Baptist Theological Seminary, New Orleans, USA, ⁶Israel Antiquities Authority, Jerusalem, Israel, ⁷University of Groningen, Groningen, Netherlands, ⁸Australian Nuclear Science and Technology Organisation, Sydney, Australia

Gezer is among the most prominent ancient city mounds in Israel, and exceptionally well-attested in historical sources. During the Bronze and Iron Ages, Egyptian, Biblical and Assyrian sources associate it with activities and conquests of specific local rulers and foreign invaders. Thus, Gezer provides a rich opportunity to test correlations between archaeology and text using a ¹⁴C-based local site chronology. Though Gezer has been the subject of intense excavation, minimal radiocarbon data was available until recently. Here we present more than 70 new dates from the Middle Bronze Age (MBA) through Iron Age levels, obtained via targeted sampling of previously exposed sections as well as active excavation. The new chronological model clarifies many aspects of the site history and contributes to region-wide debates. For example, we obtain early dates for the construction and destruction of the MBA city, and evidence countering low Philistine and Iron Age chronologies. In one part of the site, radiocarbon led to exceptionally large corrections of up to 300 years, helping to identify errors in stratigraphic interpretation and pottery-based dating, and modifying the site-wide correlation of remains; in the process, we revealed previously unrecognised and elusive evidence of resettlement during the early Late Bronze Age. By comparing the new site chronology with texts and the ¹⁴C-based Egyptian chronology, we can also present a fresh evaluation of possible associations of destruction layers and monumental architecture with historical figures.

A03_P01

Comparing Apatite and Collagen Radiocarbon dates from a 16th century Cemetery Context – El Japón, Xochimilco, Mexico City

Alarcón Tinajero E^1,2,  Hadden C², Cherkinsky A², Villegas Camposeco B³, Gómez-Valdés J^3,4

¹Department of Anthropology, University of Georgia, Athens, United States, ²Center for Applied Isotope Studies, University of Georgia, Athens, United States, ³Escuela Nacional de Antropología e Historia, Posgrado en Antropología Física, Mexico City, Mexico, ⁴Instituto Nacional de Antropología e Historia, Mexico City, Mexico

El Japón is a sixteenth century hamlet site occupying the marshlands of the southern Basin of Mexico in central Mesoamerica. Radiocarbon dating and OxCal modelling of human bone collagen (n=11) identifies a range of burials at El Japón cemetery from 1550-1650 cal. CE. The radiocarbon chronology identifies use of this rural settlement well after the onset of colonial government-sponsored relocation of Indigenous people to larger settlements – congregaciones. Radiocarbon dating in historic archaeology often takes a secondary role in comparison to artifact typologies and reliance on historical records – the Basin of Mexico is no exception. Historically documented information in this work refines chronological modelling beyond stand-alone calibration. Stable isotopic study of bone samples demonstrates similar sources of dietary protein and carbohydrates. Similarity of carbon sources for bone apatite and collagen offers security that both bone fractions are viable radiocarbon dating opportunities. Recent extension of this work examines apatite radiocarbon dates (n=6) from the same bone samples when restricted collagen quality parameters are met – atomic carbon-nitrogen ratios of 3.2-3.3 and collagen yield of 10-20%. No significant difference is found between paired collagen and apatite dates for five of six individuals. Radiocarbon dates from human bone samples in this primarily terrestrial dietary context can be successfully acquired from either collagen or apatite fractions.

A03_P02

Defining the chronology of Teotônio, a pre-Columbian archaeological site in Amazonia

Bentley M¹,  Becerra-Valdivia L¹, Kater T², Pereira Furquim L², Linscott B¹, Chivall D¹, Bronk Ramsey C¹

¹Oxford Radiocarbon Accelerator Unit, School of Archaeology, University of Oxford, Oxford, United Kingdom, ²Museu de Arqueologia e Etnologia, Universidade de São Paulo, São Paulo, Brasil

Pre-Columbian Amazonia contains a rich archaeological record indicative of complex cultural activity starting at 12,000 cal BP. The site of Teotônio, Brazil, shows a long history of human occupation, containing the oldest anthropogenic black-earth soils in the Amazon (~4,500 BCE) and early evidence of plant domestication.¹ The presence of distinct pottery traditions at the site also mark the complexity and organisation of manufacturing among ancient indigenous communities.² As such, Teotônio offers an important opportunity to better understand the human landscape in SW Amazonia during the late Holocene. Current work by the ‘Human-Environment Relationships in pre-Columbian Amazonia’ project aims to disentangle human-environment dynamics in the region, but study at Teotônio is limited by poor chronological constraint. To resolve this, we present the results of a radiocarbon dating and Bayesian modelling programme that defines the chronology at the site, enabling the framing of Teotônio within regional archaeological and paleoecological evidence.³ With a chronology in place, we also present the results of organic residue analysis, which point to the function of ceramic traditions through time.

1.           Watling, et al., 2018. Direct archaeological evidence for Southwestern Amazonia as an early plant domestication and food production centre. PloS one, 13.

2.           Almeida and Moraes. 2016. A Cerâmica Polícroma do Rio Madeira, in: Barreto, C., Lima, H.P., Betancourt, C.J. (eds.), Cerâmicas Arqueológicas da Amazônia. Rumo a uma sintese. Iphan, Brazil.

3.           Lombardo, et al., 2018. Alluvial plain dynamics and human occupation in SW Amazonia during the Holocene: A paleosol-based reconstruction. Quaternary science reviews, 180.

A03_P03

TAR PRODUCTION IN THE MEDIEVAL BOHEMIA TRACKED THROUGH GAS CHROMATOGRAPHY AND RADIOCARBON DATING

Brychova V¹, Krofta T², Svetlik I¹, Pachnerova Brabcova K¹, Petrova M¹

¹Czech Radiocarbon Laboratory, Department of Radiation Dosimetry, Nuclear Physics Institute CAS, Prague, Czech Republic, ²Department of Information Sources and Landscape Archaeology, Institute of Archaeology of the CAS Prague, Prague, Czech Republic

Accurate dating of tar kilns is crucial not only for understanding economic history but also for historical anthropology and environmental history. The historical production of tar in Bohemia is one of the neglected topics, although tar was an indispensable substance with a wide range of applications, and evidence of its production in Bohemia is dated back to the Neolithic. Dry distillation of coniferous wood leads to different types of products. A liquid organic phase, tar, is rich in diterpenic compounds, mostly retene, abietic acid and its derivatives. From the analysis of several archaeological pottery and soil samples, it is known these compounds can survive in a depositional environment over a long time scale. In this study, we sampled charcoal, pottery, and charred resinous residue from a supposedly medieval tar kiln in Brdy mountains (Central Bohemian region). Samples of pottery and resinous surface residues were subjected to solvent extraction and gas chromatography analysis to scan organic compounds preserved. Samples of charcoal and charred residue were radiocarbon dated. Pottery and charred residues solvent extracts differed in organic compound composition and concentration. Pottery extracts were dominated by long and very long fatty acids with a contribution of diterpenic residues - retene and abietic acid derivatives. Radiocarbon dates of charcoals fall into 12th century AD. Radiocarbon dating of pottery extract or surface residue through a more compound-specific approach is under further study.

A03_P04

¹⁴C preparation protocols for archaeological samples at the LMC14, Saclay, France.

Dumoulin J¹

¹CNRS, Saclay, France

The LMC14 (Laboratoire de Mesure du Carbone 14) and its AMS ARTEMIS is the national facility dedicated to high-precision radiocarbon measurement for five French institutions (CNRS, CEA, IRD, IRSN, Ministère de la Culture). Around 4000 samples of different types of organic matters and carbonates are prepared and measured every year (Dumoulin et al. 2017). Radiocarbon analysis of very small samples (below 0.2 mg of carbon) has also been explored (Delqué-Kolic et al. 2013) and modified graphitization procedures combined with a specific protocol of measurement are now used when the carbon content is low (Moreau et al. 2020). Samples like archaeological iron (Leroy et al. 2015) as well as water (Dumoulin et al. 2013) are also analyzed. Since 2017 and our last status report, we have developed new protocols to expand our range of datable samples and take into account the expectations of new archaeological projects. The specific protocols developed for dating cellulose (wood), oxalates (rock art) or lead white (cosmetics and paintings) will be detailed. The results obtained for artifacts containing various carbon contents as paint, leather, wax or pearl will also be presented.

A03_P05

OSL mortar dating inter-comparison study. The second round of MODIS, MOrtar Dating Inter-comparison Study

Panzeri L¹, Martini M¹, Maspero F¹, Galli A¹, Urbanova P², Guibert P², Sanjurjo Sánchez J³

¹Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca and CUDAM, Milano, Italy, ²(2) Archéosciences-Bordeaux UMR 6034, CNRS-Université Bordeaux Montaigne, Bordeaux, France, ³(3)          Instituto Universitario de Geología, Universidade da Coruña, A Coruña, Spain

Two physical dating methods currently enable us to date binders: radiocarbon (¹⁴C) dating and optically stimulated luminescence (OSL). During the first MODIS (MOrtar Dating Inter-comparison Study), which was initiated by specialists in ¹⁴C dating in 2014, two laboratories with expertise in luminescence dating joined the group. They attempted to apply the OSL dating to mortar samples selected for the MODIS study.

Due to the lack of a detectable signal when using “the single grain” procedure on these samples, both OSL laboratories based the dating process on the analyses of coarse quartz fractions measured by the multigrain technique. The results obtained showed general agreement both between OSL laboratories and with ¹⁴C dating results. Following this first step, a new inter-comparison experiment was set up in 2018 during the Mortar Dating International Meeting (Bordeaux, FR).

When applying the OSL method, it is necessary to evaluate environmental dose rate received by each sample. The context in situ from which mortar samples are extracted thus needs to be known when OSL dating is used, contrary to the ¹⁴C method.

As the needs for the selection of samples convenient for an inter-comparison are not the same between ¹⁴C and OSL, it has been decided to choose two different sample sets, one to share between the radiocarbon labs and one for the OSL dating. As for the OSL samples the Bordeaux group proposed three samples that were available in a sufficient quantity to be divided between participants. The data obtained within this inter-comparison will be discussed.

A03_P06

Identification of high-status medieval individuals by Bayesian chronological modelling of precise ¹⁴C ages

Meadows J^1,2, Lemm T¹, Homann A³, Nösler D⁴, Krause-Kyora B⁵, Jungklaus B, Hamann C²

¹ZBSA (Centre for Baltic and Scandinavian Archaeology), Kiel, Germany, ²Leibniz-Laboratory for AMS Dating and Stable Isotope Research, Christian-Albrechts-University Kie, Kiel, Germany, ³Städtisches Museum Schloß Salde, Salzgitter, Germany, ⁴Archäologische Denkmalpflege des Landkreises Stade, , Germany, ⁵Institute of Clinical Molecular Biology (IKMB), Christian-Albrechts-University Kie, Kiel, Germany

Excavations in 1992-93 at the Harsefeld abbey, in Stade, northern Germany, recovered 26 skeletons from the burial ground of the Udonen family. Graves were unmarked, but the Udonens, also known as the Counts of Stade, are historically well-documented. The first count buried at Harsefeld was Heinrich (d.975/976). Count Udo was killed during a Viking raid on Stade in 994; his nephew Siegfried was injured in the same attack and died a few months later. Other documented burials include women born elsewhere, such as Mechtild of Swabia (died before 1016). The latest burials predate a destructive fire recorded in 1236.

We aim to identify each skeleton with a historically documented individual, through a combination of osteological, genetic, and isotopic analyses, including Bayesian chronological modelling to estimate the birth and death dates of each skeleton. After recording age-at-death, sex, height, pathologies and trauma, each individual was sampled for ancient DNA, ¹⁴C, δ¹³C, δ¹⁵N, δ³⁴S and ⁸⁷Sr/⁸⁶Sr isotope analyses. Where possible, we dated both a rib and a petrous bone from each individual.

Our chronological model combines 47 ¹⁴C ages (with allowance, where indicated, for modest ¹⁴C reservoir effects) with collagen residence time estimates based on age-at-death and the skeletal element dated, stratigraphic constraints on the sequence of burials, and archaeogenetic kinship constraints on the maximum differences between birth dates. It produces a chronology with generational precision, permitting individual skeletons to be identified using complementary information such as their region of origin, injuries or illnesses.   

A03_P07

¹⁴C dating of mortars from Monastery Hill in Tyniec, Poland

Michalska D¹, Krąpiec M², Gronowski M^3,4, Łyczak M^5,8, Bojęś-Białasik A⁶,  Kamińska M⁷

¹Institute of Geology, Faculty of Geographical and Geological Sciences, Adam Mickiewicz University, Poznań, Poland, ²AGH University of Science and Technology, Faculty of Geology, Geophysics and Environmental Protection, Mickiewicza Av. 30, 30-059 Krakow, Poland, ³Benedictine Abbey, Tyniec, Poland, ⁴Institute of History, University of Silesia, Katowice, Poland, ⁵Archaeological Company FRAMEA, ul. Na Kozłówce 4a/10, 31-664 Krakow, Poland, ⁶History of Architecture and Monument Preservation, Faculty of Architecture, Krakow University of Technology, ul. Kanonicza1, 31-002 Kraków, Poland, ⁷Institute of Art History of the Jagiellonian University , ul. Grodzka 53, 31-001 Krakow, Poland, ⁸Institute of Archeology, Department of Historical Sciences, Cardinal Stefan Wyszyński University, ul. Wóycickiego 1/3, 01-938 Warsaw, Poland

The Benedictine Abbey in Tyniec is the oldest existing monastery in Poland (11 cent. AD). The historic walls of the Monastery have survived to this day and crown the limestone hill on the Vistula River. The geological structure of the surrounding area is of great importance and is reflected in the composition of the mortars.

In vicinity of Tyniec one may observe outcrops of Upper Jurassic limestones represented by two facies: bedded limestones with cherts and massive limestones. Recently, it was discovered that the monks not only fortified the Tyniec hill but also partly built it up with loess. Additionally, a massive "stepped" stone platform was later built to strengthen the edge of the hill.

The mortars radiocarbon dating provides the first attempt to obtain the wide chronology of the extension of Tyniec walls. Petrographic analyzes were used to characterize the binder and aggregate from mortars, especially to identify the carbonaceous components like not totally burnt limestone fragments, lime lumps or secondary calcite. Mortars were analyzed using scanning electron microscope with electron dispersive spectrometer and polarizing light microscope. Different pretreatment and sample separation protocols were applied to illustrate the huge influence of mortar components and the local geological structure on the ¹⁴C measurement results.

In addition to the mortar analyzes, ¹⁴C measurements were also made for charcoal and wood samples from Tyniec Abbey. Radiocarbon dating was performed on the selected fractions using Accelerator Mass Spectrometry (AMS).

A03_P08

Modeling the actual age of mortars - experimental research

Michalska D¹, Pawlyta J²

¹Adam Mickiewicz University, Institute of Geology, Poznań, Poland, ²Department of General Geology and Geotourism, AGH University of Science and Technology Faculty of Geology, Geophysics and Environmental Protection, Kraków, Poland

An attempt to model the age of mortar were made on the basis on the results of the ¹⁴C measurement for the bulk material together with the knowledge of the δ¹³C of various mortar components. In order to assess the variability of isotopic fractionation during CO₂ absorption by mortar carbonates depending on the environmental conditions and the type of mortar, the δ¹³C measurements were performed for the mortars from Kraków. Similar analyzes were also carried out for natural limestone and for the experimental mortars produced in the laboratory. Knowledge about the isotopic fractionation allows to make an age correction for mortars along with the verification of such correction based on the percentage estimation of the carbonate components. The obtained results were compared with earlier attempts to model the age of mortars from Sussita (Sea of Galilee).

A03_P09

Radiocarbon dating and Sr isotope analysis of cremated bones excavated from the Ishibotokedani site in Binmanji Temple, Shiga prefecture, Japan

Sawada R¹, Minami M¹, Wakaki S²

¹Nagoya University, Nagoya, Japan, ²KOCHI JAMSTEC, Nangoku, Japan

Numerous cremated bones have been excavated from the Ishibotokedani archaeological site located adjacent to Binmanji Temple, Shiga Prefecture, Japan. It is believed that people related to Binmanji, such as the priests of Binmanji and the surrounding residents, were buried here. Since Binmanji was burned down in the 16th century, few documents remain. Thus, in this study, ¹⁴C dating, Sr isotope analysis, and trace element analysis of approximately 30 cremated remains excavated from survey areas A, D, F, and G were conducted to investigate the age and residence of the buried people.

Radiocarbon dating of the cremated bones from the Ishibotokedani site indicate that the cremated bones from area A date from the 12th to 14th century, those from area D belong to the 13th century, those from area F date from the 12th and 13th centuries, and those from area G date back mainly to the 14th century. This is consistent with the period of activity of Binmanji (12th–16th centuries), as established by ancient documents.

The ⁸⁷Sr/⁸⁶Sr isotopic ratios of the cremated bones ranged from 0.70938 to 0.71079. Compared to the ⁸⁷Sr/⁸⁶Sr isotopic ratios of the geochemical samples of the surrounding areas, the cremated bones showed 87Sr/86Sr isotopic ratios similar to soil of the Ishibotokedani (0.70942−0.71040) and the adjacent Seri River water (0.70926−0.71002). This indicates that the people buried in the Ishibotokedani site mainly ate crops grown in the vicinity of Binmanji or the Seri River.

A03_P10

Extensive survey on radiocarbon dating of organic inclusions in historical mortars

Pachnerova Brabcova K¹,  Kundrat P¹, Krofta T¹, Suchy V¹, Petrova M¹, John D^1,2, Kozlovcev P³, Kotkova K³, Fialova A³, Valek J³, Svetlik I¹

¹Nuclear Physics Institute of the CAS, Praha, Czech Republic, ²Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Praha, Czech Republic, ³Institute of Theoretical and Applied Mechanics of the CAS, Praha, Czech Republic

Direct radiocarbon dating of historical mortars remains challenging due to complex processes during mortar maturation that can mislead the interpretation. Organic inclusions in the mortars, such as charcoals, seeds, microbiotas, wood, or bones, represent important alternative or complementary dating material providing the date as a terminus post quem.

This work adds to the determination of how reliable such organic inclusions can be for radiocarbon dating. For the analysis, we have collected 129 charcoals from five different early to late medieval castles and churches located throughout the Czech Republic. The architectural objects were chosen to meet the following criteria:  i) known age documented in written sources and optimally also obtained through other dating method or complemented with radiocarbon dating of samples other than mortar-derived ones; ii) known history of repairs and maintenance; iii) age falling before 1650 AD to avoid issues related to inconclusive radiocarbon dating in the early modern period.

Most of the samples were measured on our new AMS MILEA. The results demonstrate that a notable fraction of inclusions corresponds to charcoals from old wood, often a few hundred years old when raising the object, presumably originating from timber cut-offs. For some sites we found several samples related to later repairs, despite trying to limit the sampling areas to original masonry only. Based on this comprehensive study, we recommend a rather high number of samples be collected per dated object, at least 5 - 10 for sites with uncomplicated building history, so that radiocarbon dating provides reliable results.

A03_P11

¹⁴C dating for MODIS 2 carbonate mortars – do time and size matter?

Pawełczyk F¹, Gu Y^2,3, Piotrowska N¹, Ustrzycka A¹, Hajdas I²

¹Institute of Physics - CSE, Silesian University of Technology, Gliwice, Poland, ²Laboratory of Ion Beam Physics, ETHZ, Zurich, Switzerland, ³Laboratory of AMS Dating and the Environment, School of Geography and Ocean Science, Nanjing University, Nanjing, China

In our work we present a procedure applied for the ¹⁴C dating of three samples of mortars from the project MODIS 2, which is an international laboratory intercomparison. The samples selected for the exercise comprise three different mortars:

1) MODIS2.1: mortar from Finnish medieval church

2) MODIS2.2: mortar from Swedish medieval church

3) MODIS2.3: mortar from Spanish early Christian basilica

The material was sieved and three different size fractions were separated: <45 micrometers, 45-63 micrometers, and >63 micrometers. The composition of each fraction was analyzed under the binocular microscope.

The mortar carbonates were dissolved under vacuum conditions, using H₃PO₄ and the CO₂ coming from following time intervals was collected: 1-3sec, 4-6sec, 7-9sec, 10-12sec, and remaining CO₂. Also, the bulk carbonate from each size fraction was dated. In general, a growing age trend was observed with older age for samples from later time intervals, and the oldest for remaining CO₂ fraction.

The CO₂ was graphitized using AGE system at the ETH or Gliwice, or introduced to gas ion source of the MICADAS at the ETH. Moreover, the charcoal fragments were discovered in a sample MODIS2.2. The age of this charcoal was measured in ETH and Gliwice laboratories to 1090±30 BP and 950±30 BP, respectively.  For comparison, the age of carbonate fractions for this mortar ranged from 600 to over 2000 BP.

In addition, the stable isotope IRMS measurements were performed for carbonates from different size fractions and bulk material using the CF-IRMS IsoPrime coupled to Multiflow device.

A03_P12

RADIOCARBON DATING OF POORLY PRESERVED BONES FROM CHURCH OF ST. WENCESLAV IN PLASY, CZECH REPUBLIC

Petrova M¹, Sneberger J^1,2,3,4, Brychova V¹, Pachnerova Brabcova K¹, Svetlik I¹

¹Department of Radiation Dosimetry, Nuclear Physics Institute of the Czech Academy of Sciences, Prague, Czech Republic, ²Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Prague, Czech Republic, ³Department of the History of the Middle Ages of Museum of West Bohemia, Pilsen, Czech Republic, ⁴Department of Natural Sciences and Archaeometry, Institute of Archaeology of the Czech Academy of Sciences, Prague, Czech Republic

Rescue archaeological research at the Church of St. Wenceslav in Plasy, Czech Republic, revealed a burial ground. Radiocarbon dating of the remains (teeth, bones) was used to explore the history of the pre-monastic settlement. Due to a low quality of the analysed samples, a standard acid-base-acid sequence was followed by ultrafiltration to purify gelatinized fraction. The yields, dates and stable isotope ratios of non-ultrafiltered and ultrafiltered samples are compared and the impact of the ultrafiltration on the data interpretation is discussed.

A03_P13

Stone-paved cellars in the Danish Stone Age? Research potential and strategies for radiocarbon dating at rescue excavations

Brinch M¹, Philippsen B¹, Groß D¹, Kanstrup M²

¹Museum Lolland-Falster, Nykøbing F, Denmark, ²Aarhus AMS Centre, Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark

We present the excavation results from a Middle Neolithic site associated with the Funnel Beaker Culture. During a rescue excavation, a recessed area was recorded within two overlaying house features which was constructed using different sized pebbles. The arrangement and form of the feature clearly indicated anthropogenic origin and is understood as belonging to one of the house structures. Consequently, it is interpreted as a paved cellar – a feature yet unknown from Danish Stone Age archaeology. Additional features at the site were several pits and postholes that indicated the presence of a palisade or fence structure with up to seven different parallel lines. Indirect dating of the features through associated organic material has shown that the fence or palisade has existed contemporaneously with the houses and can, hence, be interpreted as belonging to the same settlement. We present the results from the excavation and integrate the site in its regional archaeological landscape.

Finally, we discuss the radiocarbon dating strategies for rescue excavations both on the scale of individual features as well as for entire development projects. We show how targeted sampling and analysis can preserve the research potential of those sites for future research.

A03_P14

Human occupation sequence in the context of an archaeological site of Salapunku (Cusco, Peru)

Sieczkowska D¹, Rakowski A², Pawlyta J⁴, Bastante J³,1 Ziółkowski M¹

¹ University of Warsaw, Warsaw, Poland, ²SUT, Gliwice, Poland, ³National Archaeological Park of Machupicchu, Cusco, Peru, ⁴AGH, Kraków, Poland

The Salapunku archaeological site is located within the Machupicchu National Archaeological Park in the Cusco area of Peru. Although Salapunku is located in the area of the Inca-related Machupicchu, within the archaeological site during the archaeological work it was possible to distinguish different moments of multicultural presence which allowed the creation of a sequence of human occupation in the study region. The Inca occupation phase is the most recent use of the site, but in earlier periods there were human settlements in this area associated with the Killke culture and even with human presence during the local formative period. Previous research on the chronology of the site was based on typological analyses of pottery and other artefacts found during excavations. With research extended by radiocarbon analyses, it has been possible to establish a chronology of settlement development in this part of the Park considered to be the gateway to the Cordillera of Vilcabamba. The purpose of this presentation is to show the recent findings of human presence in this area and its possible relation to climate/environment changes.

A03_P15

Radiocarbon dating of Herodium, the Mountain palace-fortress, and the monumental burial complex of Herod the Great

Regev L¹, Porat R², Botosh A², Leibner U², Regev J¹, Mintz E¹, Boaretto E¹

¹Weizmann Institute of Science, Rehovot, Israel, ²The Hebrew University of Jerusalem, Jerusalem, Israel

The site, situated between Jerusalem and the Judean Desert, comprises several palaces and complexes built mostly by Herod the Great, who ruled over the region during the first century BC under Roman rule. The main palace was built as a round fortress, five stories high (ca. 25 meters), with a tower reaching the estimated height of up to 40 meters. The fortress was later covered by earth, creating a volcano-like shape. The site was excavated for over 50 years, mainly under the late archaeologist prof. Ehud Netzer from the Hebrew University in Jerusalem.

Five main construction phases were identified at the fortress: (a) its construction; (b) modifications at the east wing of the complex; (c) its covering by earth, forming the artificial mount; (d) the Great Revolt (70 AD); and (e) a later phase of tunnel diggings during the Bar-Kokhba revolt (2nd century AD).

Due to the region's dry climate, abundant wooden remains were found at the site. From which, in-situ construction beams from all construction phases were sampled and dated by cellulose extraction and radiocarbon dating. The results confirm that the first three phases are contemporaneous to Herod’s reign, while the source of the beams used by the rebels during the Bar-Kokhba revolt is somewhat surprising.

A03_P16

Modelling temporality of a Late Neolithic-Early Iron Age cemetery at Mang de Bargen, Germany

Rose H¹, Schaefer-Di Maida S², Kneisel J²

¹Zentrum für Baltische und Skandinavische Archäologie (ZBSA), Schleswig, Germany, ²Institute of Pre- and Protohistoric Archaeology, CAU Kiel, Kiel, Germany

Round barrows dating to the Late Neolithic and Early Bronze Age form visible funerary monuments in today’s landscape. They have revealed extraordinary oak-coffin graves that can be relatively dated using typo-chronology, but little is known about the temporal relationships between these and later, more inconspicuous, re-burials in the barrows. We present new results from the Late Neolithic-Early Iron Age cemetery at Mang de Bargen in Schleswig-Holstein, Germany. Here, a group of round barrows were first recorded in the 1970s and part of these were excavated over several field campaign in the last two decades. We returned to the site in 2016-2019 and conducted thorough investigations and revisions of 20 barrows and an urn cemetery. This also resulted in 106 new radiocarbon dates on 84 burials and related features, offering the first possibility to model the temporality of a dynamic funerary landscape in northern Germany. There is no direct stratigraphic link between the barrows at Mang de Bargen, but individual barrows are often constructed in more phases and using Bayesian chronological modelling we estimate their temporal relationships and if primary and secondary burials were interred within ‘living memory’ of the last internment. More changes of funerary practices can be detected at Mang de Bargen, such as the introduction of cremation and the transition from burials in barrows to burials in flat graves.

A03_P17

Variation of ¹⁴C results from different samples in an archaeological context

Seiler M¹, Svarva H¹, Rzadeczka-Juga I¹, Nadeau M¹

¹The National Laboratory for Age Determination, NTNU University Museum, Trondheim, Norway

Archaeological contexts contain different materials and pieces that can be selected for radiocarbon dating. While one tries to select short lived samples such as plant material, charred seeds, or charcoal from shorter lived tree species, the connection between the samples selected and the event to be dated might be uncertain. Financial considerations prevent the measurement of multiple samples to date single contexts such as a cooking pit or even a dwelling. The small amount of material needed by AMS often leads to the measurement of only one charcoal piece or hazelnut shell.

We analysed different pieces from large samples of mixed charcoal from archaeological excavations in Norway to assess how representative a single piece is for the sample as a whole. We found that the results for the same wood species do match well, while there is a discrepancy between different wood species, particularly older ages for longer-lived tree species, which could be explained by the ‘old wood’ effect. The magnitude of this effect varies between sites, and is more relevant for radiocarbon results with smaller uncertainties.

A03_P18

Archaeological sandals from the Balsas Basin, Mexico

Solis C¹, Martínez Carrillo M², Rodríguez Ceja M¹,  Xelhuantzi López M³, Alvarado J³, Sánchez Martínez F⁴

¹Instituto de Física. Universidad Nacional Autónoma de México., Mexico City, Mexico, ²Facultad de Ciencias, Universidad Nacional Autónoma de México., Mexico City, México, ³Subdirección de Laboratorios y Apoyo Académico, INAH., Mexico City, México, ⁴Centro INAH Morelos, Cuernavaca, Mexico, ⁵Licenciatura en Ciencia Forense, Facultad de Medicina, UNAM., Mexico City, México

The Balsas basin is a critical geographic region for studying the settlement and development of ancient human populations in Mexico. Located in the central region of Mesoamerica, the Balsas River basin offered numerous rock shelters that provided safe shelter, water, and stable climatic conditions to hunter-gatherer groups that, according to archaeological evidence, would have settled 4,000 years B.P.

In the Balsas Basin caves, professional searchers of archaeological pieces collected various objects, including vegetable fiber sandals (huaraches). The exact place of origin and context from which the pieces were extracted are unknown.

In 1999 the collection of fifty huaraches was recovered by the National Institute of Anthropology and History (INAH), which constitutes one of the largest collections of pre-Hispanic huaraches recorded.

The first study of the pieces consisted of the macroscopic analysis of each of the huaraches, considering the degree of conservation, structure, morphology, size, and particular characteristics. Then, the botanical identification of the vegetable fibers used to manufacture the pieces was carried out to determine the origin of the plants used for its manufacture. Because there are pieces of different sizes and in different conservation conditions, the possible use of the pieces was determined.

This work presents the radiocarbon-AMS dating of the vegetable fibers of several huaraches to provide information that allows them to be in time within the Balsas Basin area. In the complementary analyses, we sought to identify the plants by stable isotope analysis and to confirm it with genetic analysis. 

A03_P19

Dating the concealment of the Library Cave at Mogao, Dunhuang

Staff R¹, Liu R², Pollard M³, Zhao Y⁴, Yu Z⁴, Zhang X⁴, Monteith F⁵, Guo Q⁴, Su B⁴

¹University Of Glasgow, Glasgow, United Kingdom, ²British Museum, London, United Kingdom, ³University of Oxford, Oxford, United Kingdom, ⁴Dunhuang Academy, Dunhuang, China, ⁵Northwest University, Xi'an, China

The Mogao Grottoes, located 25 km southeast of Dunhuang in Gansu province, China, contain 735 caves carved into the rock. Of these, the majority of the 492 caves in the south section contain Buddhist art, many of which are regarded as the finest extant early Buddhist paintings in China. As a UNESCO World Heritage Site situated at the eastern end of the Silk Road, the construction and development of the Dunhuang Grottoes vividly illustrates the arrival and transformation of Buddhism in China. However, the full potential of the site to inform the broader field of Buddhist studies is limited by a paucity of robust chronology.

Chief among the grottoes, the so-called 'Library Cave', accidentally rediscovered in 1900, housed >60,000 manuscripts and drawings dating from the first millennium CE. Among the myriad questions relating to the site, the date of the concealment of the Library Cave has been highly debated; it is directly linked to the nature of the manuscripts recovered from the Cave, and the broader historical context in which the concealment took place.

Here, we apply radiocarbon dating and Bayesian chronological modelling to narrow down the timing - and hence the likely circumstances - of the Library Cave's concealment.

A03_P20

AMS, Historical and Archaeological Dating in the Oponice Castle 

Styková B^1,3, Styk M², Světlík I¹, Megisová N¹, Petrová M¹, Repka D²

¹Department Of Radiation Dosimetry, Nuclear Physics Institute CAS, Řež - Husinec, Czech Republic, ²Department of Archaeology Faculty of Arts, Constantine the Philosopher University in Nitra, Nitra, Slovakia, ³Regional centre Banská Bystrica,The Monument Board of the Slovak Republic, Banská Bystrica, Slovakia

The 5th season of Oponice castle excavation in 2022 was located in the lower castle´s courtyard. There was discovered original clay floor strongly burned with charred plank and a rectangular stone-brick structure laying on it. This structure has collapsed upper part with a fallen low brick arc.  In whole space were also documented numerous stove tiles fragments same as the discovery of one clay mould for the production of front heating walls of chamber tiles. Based on it this structure was identified as a pottery kiln dated to the second half of the 16th till the first half of the 17th century AD by the findings from excavated layer, which was probably related to kiln destruction. At the same time, the written sources mention big fire in 1645 caused the end of the castle. Different types of samples were collected for AMS dating to CRL (Czech Radiocarbon Laboratory) in Prague. This sampling was focused on site formation process determination of pottery kiln use and the way of its destruction. Applying of Bayesian analysis tent to improve overall dating and historical events recreating. The results and methodology of the radiocarbon dating will be presented in poster form.

A03_P21

Radiocarbon dating of multiple materials for clarifying of medieaval settlement formation in the outskirts of Prague Castle (CZ).

Tomanová P¹

¹Nuclear Physics Institute CAS, Řež, Czech Republic, ²Insitute of Archaeology of the CAS Prague, Prague, Czech Republic

An archaeological excavation was conducted in the street U Kasáren in the Prague Castle area (Czech Republic) in 2020. The excavation revealed an intensive early mediaeval settlement of the 10th-13th centuries. The settlement features included different types of house constructions (sunken houses, masonry construction), pyrotechnical (possibly metallurgical) features and evidence of several fire events. Archaeobotanical analysis of selected samples proved the earliest evidence of viniculture in the outskirts of Prague Castle area, showed presence of some extinct species of weeds and contributed to the research of crops distribution in the early mediaeval central places.

However, the archaeological data allow only a rough dating of the researched settlement and it is hardly possible to date individual formation phases of the site. Only a limited number of datable pottery fragments was obtained. Furthermore, the research circumstances allowed us to document the area in separate sections, which makes it difficult to interconnect the data in a clear picture of the formation of the site.

This poster shows how radiocarbon dating of various materials (animal bones, archaeobotanical samples) can clarify the absolute chronology of the formation of the settlement in the outskirts of Prague Castle (e.g. the shift from log houses to masonry constructions, the beginnings of metallurgical activity and the viniculture in this area).

A03_P22

Pre-screening of lime mortars for ¹⁴C dating – Preliminary results

Wojcieszak M^1,2, Fontaine L¹, Hayen R¹, Elsen J³, Van den Brande T¹,  Oostvogels A¹, Ligovich G¹, Rich M¹, Boudin M¹

¹Royal Institute for Cultural Heritage (KIK-IRPA), Brussels, Belgium, ²Evolutionary Studies Institute (ESI), University of the Witwatersrand, Johannesburg, South Africa, ³Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium

The oldest known use of lime mortars dates from the Neolithic period. The production process incorporates atmospheric CO₂ and gives rise to the formation of calcium carbonate (CaCO₃). Radiocarbon dating of anthropogenic lime carbonates was first developed in the 60’s. These first results were very promising and the French researchers Jacques Labeyrie et Georgette Délibrias already pointed out that microscopic observation should be performed to check out the eventual presence of foraminifera (microfossils) susceptible to false the date result, since they are made of very ancient carbonates. Other types of carbonates can be present in mortars because of the mortar formation process and possible subsequent weathering. These carbonate contaminations are unburnt or underburnt limestone used for lime production, fossil carbonates such as shell fragments in sands, reused limestone and mortars crushed and used as aggregate, or specific minerals containing carbonates. Their presence results in a lower ¹⁴C/¹²C ratio which generates an older date, as they are radiocarbon free. Another category of carbonates are secondary carbonate deposits, which can cause an increase of the ¹⁴C/¹²C ratio but can also incorporate older carbon. Using the stepwise acid hydrolysis method on the binder (and when possible pure lime inclusions dating), this project aims to develop a pre-screening method, by means of different analytical techniques such as polarized light microscopy, Fourier transformed Infrared spectroscopy, cathodoluminescence and thermal analyses (TGA-DSC) to verify the “mortar quality” in order to decide whether the radiocarbon date will be reliable or not.

A03_P23

AMS dating data on excavations at the citadel of Yaroslavl solve the dispute between archaeologists and dendrochronology specialists

Engovatova A¹, Cherkinsky A³, Matskovsky V², Karpukhin  A¹, Zazovskaya E²

¹Institute of Archaeology RAS, Moscow, Russian Federation, ²Institute of Geography RAS, Moscow, Russian Federation, ³University of Georgia, CAIS, , Athens

During the excavations in 2004-2022 in the citadel of Yaroslavl (Central part of

Russia) were found nine sanitary burials of the time of the defeat of the city in

1238. For a more accurate dating of the event, samples were taken from each of the

nine burials. All 37 AMS dates (UGAM) obtained fit into a narrow data interval - when all the

results were combined, a calibrated date of 1221–1259 was identified.

In 2020, archaeologists unearthed another burial. Dendro dates obtained for this

burial did not coincide with previous results.  Ten oak samples have been

successfully cross-dated, and a floating chronology 177 years long has been built.

As there is no oak tree-ring chronology for Yaroslavl, this floating chronology has

been cross-dated with the nearest Smolensk oak chronology (~600 km distance to

South-West from the city of Yaroslavl). However, cross-dating statistics is not high

enough to be sure in the acquired dating. For this reason, we additionally obtained

AMS dates (IGAN) for 17 wooden samples. Some of the ¹⁴C dates overlap with

the obtained tree-ring dates, others do not. We also failed to obtain convergence on

wiggle-matching (D_Sequence, OxCal) for all the 17 AMS dates. Those seven

dates that converge, however, show earlier period for the outermost rings of the

floating oak chronology: AD 1214-1232 (95.4%).

Despite some contradictions in the acquired AMS dating results, we found better

correspondence of the seven converged dates to the archaeological context, than to

the obtained dendrochronological dates.