A04_01

The challenge of dating archaeological sites beyond ~35,000 BP: Progress and future prospects in radiocarbon dating the Palaeolithic of Eurasia

Higham T¹

¹University of Vienna, Vienna, Austria

The Late Middle and Early Upper Palaeolithic (~35-60,000 years ago), is a key period in human evolution. It witnesses the transition between a Neanderthal (and Denisovan) dominated Eurasia, to one which was exclusively occupied by Homo sapiens. Recent discoveries in archaeology, genomics, isotope geochemistry, residue analysis, dating science and more, have revolutionised our understanding of the period. We now have some answers to what were seemingly intractable big questions; did Neanderthals and Homo sapiens meet? How long was their overlap, and where did they encounter one another? But other answers remain elusive. At the heart of many of these uncertainties lies a robust chronology, so radiocarbon dating has been at the centre of many debates in the Palaeolithic.

There are many ‘legacy’ radiocarbon measurements from the Palaeolithic that are often erroneous. Over the last 10-15 years, however, there have been significant improvements in routine dating science. Three principal areas will be discussed. First, we have better measurement precision, lower backgrounds in accelerators and more accurate subtraction of laboratory derived ¹⁴C pretreatment backgrounds. Second, improvements in chemical pretreatment and sample decontamination of bone proteins and charcoal samples. Third, the application of Bayesian age modelling coupled with newer extended calibration curves, allowing the inclusion of dates from other methods and archaeological prior information.

Over the last few years >1,000 samples from more than 100 key European Palaeolithic sites have been obtained. I will discuss the results from some of these key sites across Eurasia in the wider context of the Palaeolithic.

A04_02

Investigating the co-occurrence of Neanderthals and Modern Humans in Belgium through direct compound-specific radiocarbon dating

Devièse T^1,2,  Abrams G^3,4, Pirson S⁵, De Groote I^6,7, Flas D^8,9, Semal P¹⁰, Di Modica K^3,11, Higham T^12,2

¹Aix Marseille University, Aix en Provence, France, ²University of Oxford, Oxford, United Kingdom, ³Espace Muséal d’Andenne, Andenne, Belgium, ⁴Leiden University, Leiden, Netherlands, ⁵Agence wallonne du Patrimoine, Namur, Belgium, ⁶Ghent University, Gent, Belgium, ⁷Liverpool John Moores University, Liverpool, United Kingdom, ⁸University of Liège, Liège, Belgium, ⁹University Toulouse Jean-Jaurès, Toulouse, France, ¹⁰Royal Belgian Institute of Natural Sciences, Brussels, Belgium, ¹¹University of Namur, Namur, Belgium, ¹²University of Vienna, Vienna, Austria

Determining the timing of the transition between Neanderthals and anatomically modern humans (AMHs) is crucial in archaeology and paleoanthropology. While there is increasing evidence of admixture and co-existence of the two hominin species in Central and Eastern Europe, Belgium might show a different scenario. This key area sits at the crossroads between Palaeolithic cultural facies with influences from eastern, western, and southern Europe intermingling during the Late Middle Palaeolithic and the Middle to Upper Palaeolithic transition.

Recent DNA analyses seem to indicate a hiatus in the occupation of the Belgian territory. However, this interpretation is based on a limited number of hominin specimens because of their scarcity in the archaeological record. Mousterian and Aurignacian industries, associated with Neanderthals and AMHs respectively, are present in much larger quantities. They can also be used to define the timing of both occupations.

In this presentation, we report new compound specific radiocarbon dates obtained on Neanderthal specimens from Spy, Engis and Fond-de-Forêt. We also reevaluate the chronology of the latest Mousterian and earliest Aurignacian evidence. This new data tends to confirm that there may have been a hiatus implying that Neanderthals and Anatomically Modern Humans did not co-exist in this region. These results also show how much sample preparation can impact on the AMS measurements when specimens have been heavily preserved with conservation materials (which is often the case for human remains) and their age is approaching the limit of radiocarbon dating.

A04_03

MIS-3 megafauna radiocarbon ages and blank control practices at ANSTO

Levchenko V¹,  Bertuch F¹, Smith A¹, Jenkinson A¹, Hua Q¹, Williams A¹, Kumar S¹, Yang B¹

¹ANSTO, Kirrawee DC, Australia

Reliable radiocarbon age determinations close to the limit of the method are dependent on effective pre-treatment and correction for extraneous carbon added during processing. At ANSTO this is controlled by processing continuous stream of various representative blanks to characterise major pre-treatment protocols – ABA, cellulose purification, collagen extraction, also combustion-graphitisation and hydrolysis-graphitisation procedures.

Special collections of materials with ages beyond the radiocarbon limit are used – charcoal from a million-year-old tree, MIS-5 bones from permafrost, subfossil wood, IAEA-C1 marble, and Ceylonese and commercial graphite. For graphitisation blank, the cylinder with geological CO₂ is used. Blanks ranging from ten of μg to several mg of carbon are processed for every AMS radiocarbon run. For each material and procedure, a mass dependence function for blank pMC values is constructed on the subset including the most recent few-month determinations. This allows building a representative statistic for blank variability and flags any significant blank level increases prompting a review of relevant laboratory activity.

As an example, we present the dating of Diprotodon remains from Lake Callabonna in South Australia. Diprotodons became extinct around 70-50 ka BP, period also noted by the arrival of humans to Australia. To better understand the extinction causes, a reliable determination of the species extinction time is required. To date, all diprotodon remains returned infinite ages beyond the radiocarbon limit. Our studied specimen after a set of determinations produced a finite age of 51,900+/-1200 radiocarbon years, bringing the species survival time to the times of human presence in Australia.

A04_P01

“Here we go again”: the inspection of collagen extraction protocols and why compound specific radiocarbon dating matters

Devièse T¹

¹Aix Marseille University, Aix en Provence, France

The radiocarbon dating of archaeological bones is widely used across various fields of research, most notably by palaeontologists, palaeoecologists, archaeologists and geneticists. The radiocarbon dates obtained on fossils allow scientists to reconstruct ancient ecosystems and the rates of faunal change in these communities as well as human occupations. Reliable and accurate dating is therefore hugely important. However, there are major challenges when radiocarbon dating bone specimens over 30,000 years old and there is considerable uncertainty over some of the published data.

The method currently used by most radiocarbon laboratories to date archaeological bones was developed in the 1970s and consists of a succession of chemical treatments designed to extract and purify collagen before measurement on the Accelerator Mass Spectrometer. However, for radiocarbon results to be reliable, samples must be totally free of contamination, and this is not always possible, particularly when the contaminants are cross-linked to the collagen. An alternative is to use the so-called “compound specific dating approach”, focusing on a single amino acid, hydroxyproline (HYP) within the bone collagen. Extracting and dating HYP results in excellent levels of reliability that no other method can provide.

After a description of the method’s principle, this presentation will show, with several case studies, that many dates published in the literature and obtained after less robust pretreatments can be highly inaccurate. Such errors can then lead to incorrect interpretations of dispersal and rates of change in the archaeological, climatic, and evolutionary records, as the dates are the foundation of all these models.

A04_P02

Comparison of radiocarbon dates of animal bones from Vindija and Mujina Pećina caves

Krajcar Bronić I¹,  Karavanić I², Sironić A¹, Vukosavljević N², Banda M², Smith F³, Radović S⁴

¹Division of Experimental Physics, Ruđer Bošković Institute, Zagreb, Croatia, ²Department of Archaology, Faculty of Humanities and Social Sciences, Zagreb, Croatia, ³Department of Sociology and Anthropology, Illinois State University; Department of Anthropology, University of Colorado, Normal; Boulder, USA, ⁴Institute for Quaternary Paleontology and Geology of Croatian Academy of Sciences and Arts , Zagreb, Croatia

Bone samples from two caves, Vindija (Donja Voća, NW Croatia) and Mujina Pećina cave (Plano, near Kaštela, Dalmatia), were selected for radiocarbon AMS dating at the Ruđer Bošković Institute (RBI) laboratory. Collagen extraction yielded >1% of collagen for 10 samples. From six samples the collagen yield was lower than 0.5 % and those bones could have not been dated. The low collagen yield (<1%) may produce an underestimated radiocarbon age. For comparison, bone samples were sent to Oxford Radiocarbon Accelerator Unit (ORAU) for radiocarbon dating with an additional step of ultrafiltration (UF) to select collagen fraction having molecules larger than 30 kDa. Four of them could not have been dated due to low collagen yield, five were dated in spite of low yield, and only three of them were successfully dated.

The results of delta-¹³C values of bone samples showed the same range in both RBI and ORAU laboratories, between -18.3 ‰ and -21.8 ‰, which are typical values for bone collagen. Radiocarbon conventional ages of these limited number of bone samples were comparable.

The preliminary results presented here point to the possible obstacles in radiocarbon dating of late Middle Paleolithic samples: bones are not well preserved, yield of collagen is often low, and the age is close to the limit of the radiocarbon method.

Acknowledgment: „Last Neandertals at the Crossroads of Central Europe and the Mediterranean – NECEM“ is financed by Croatian Science Foundation, HRZZ-IP-2019-04-6649.

A04_P03

Chronology of the Barabinskaya culture (south of Western Siberia): Early Neolithic

Molodin V¹,  Mylnikova L¹, Parkhomchuk E¹, Reinhold S², Nenakhov D¹

¹Institute of Archaeology And Ethnography SB RAS, Novosibirsk, Russian Federation, ²German Archaeological Institute, Berlin, Germany

In the southern part of Western Siberia Early Neolithic sites were discovered, which are characterized by flat-bottomed pottery. This allowed to distinguish the Barabinskaya culture. It is represented in settlements and ritual complexes, has a specific economic, as well as a certain set of stone and bone artifacts. The presentation offers an overview of the radiocarbon dates of the Barabinskaya culture, obtained at the Curt-Engelhorn-Centre of Archaeometry (Germany) and at the "Accelerator mass spectrometer" BIMP SB RAS (Russia). In total 32 samples were dated.

Dates obtained from the Vengerovo-2 site: (29409) 7510±26, (NSK-02843) 72014±139 BP.

19 samples have been dated from the Tartas-1 site. Six of dates origin from the dwellings: early – (NSK-1645) 7532±97, late – (29403) 7449±23 BP. Another 13 dates are related to fish conservation pits. The sample from the pit No 991 provided an early date (26158) of 8034±36 BP. For the pit No 1229 a date (29407) of 7344±24 BP was obtained.

A sanctuary at the Ust-Tartas-1 site dates from (NSK-2392) 7610±82 to (NSK-2394) 6389±57. For the pits No 18 and No 27, that accompanying the sanctuary, the following dates were obtained: (NSK-2181) 6394±64 and (NSK-2179) 7246±190 BP respectively. "Fish pits" No 7 and No 65–66 were dated of (39313) 7936±23, (39314) 7726±24 BP, (NSK-2182) 8170±71 and (NSK-2207) 8023±96 BP.

Thus, the Barabinskaya culture dates to the 7th millennium BCE with some precursors dating back to the 8th and an aftermath in the 6th millennium BCE.

Project No FWZG-2022-0006.

Keywords: Western Siberia, Barabinskaya culture, chronology.

A04_P04

Finite ages from the Mesozoic era - is bone collagen an open system ?

Taylor S¹,  Thomas B¹

¹University Of Liverpool, Liverpool, United Kingdom

The first detectable pMC results from analysis of dinosaur collagen using AMS are presented and discussed. Over 40 pMC results taken from samples of known provenances showed expected decreases in measured ¹⁴C as expected for Medieval, Roman era, and ice age bone samples, but failed to show the expected step-downs to Cretaceous and Jurassic fossilised material. This raises the question as to whether bone collagen is an open system and if so, to what extent. A literature search revealed previously published radiocarbon in carboniferous material including fossils from Mesozoic and earlier deposits. This showed that although unexpected, the data presented here have precedents. Dinosaur bone samples were sent to 2 radiocarbon laboratories. Both managed to extract collagen and dated the collagen, apatite, and bulk samples, all to finite ages. A survey of six collagen versus apatite pMC differences suggested that some Mesozoic material has experienced a degree of isotopic alteration. Twenty one pMC values from nine Mesozoic bone samples sorted by three bone fractions (collagen, apatite, and bulk) showed a largely randomised distribution that does not confirm the expectation that isotopic alteration would affect one fraction more than another. A linear trendline intersects all Mesozoic bone material, but none of the three control materials at the resolution displayed. These results are most consistent with the hypothesis that ¹⁴C in Mesozoic and possibly older materials represent a combination of primary and secondary sources, with the caveat that no known cause of secondary sourcing stands out.