Cementochronology Unravels Seasonality in Prehistory

Informations projet

CUSP

N° de convention de subvention: 846856

DOI

10.3030/846856

Projet clôturé

Date de signature de la CE 27 Mars 2019

Date de début 1 Novembre 2020

Date de fin 31 Octobre 2023

Financé au titre de

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Coût total

€ 269 002,56

Contribution de l’UE

€ 269 002,56

Coordonné par

UNIVERSITA DEGLI STUDI DI ROMA LA SAPIENZA
Italy

Periodic Reporting for period 2 - CUSP (Cementochronology Unravels Seasonality in Prehistory)

Période du rapport: 2022-11-01 au 2023-10-31

Résumé du contexte et des objectifs généraux du projet

Archaeological sites are by and large palimpsests of coarse-grained chronological resolution, with many episodes of (re-)occupation where often undifferentiated blocks of time are used as units for temporal reckoning. Ancient teeth preserve important information about past lives and deaths. One of the possible avenues for utilizing this plethora of information harbored in teeth tissues is by studying the phenomenon known as Tooth Cementum Annulation (TCA)—formation of alternating translucent and opaque bands observed in the cementum, the outer layer covering roots in teeth. Like with growth lines observed in trees that can serve to determine their ages, counting alternating increments in cementum that represent growth (summer) and dormant (winter) seasons can provide accurate estimates of age- and season-at-death in animals and humans. The methodological advances provided by cementochronological approaches can provide powerful means of temporalizing and refining our understanding of annual scheduling of site occupation. Cementochronology examines alternating incremental translucent and opaque bands that are laid down throughout life in tooth cementum as physiological responses to seasonal rhythms. Counting pairs of bands on thin sections under polarized transmitted light provides accurate age estimates. The outermost band represents the season-at-death, which is used to infer seasonality of site occupation. This method is particularly relevant for prehistoric periods when seasonal scheduling of lifeways was of paramount importance.

Moreover, in the most recent anthropological scholarship, understanding the seasonal nature of many social institutions and social groups in the past goes beyond the concerns about the scheduling of subsistence activities in relation to the availability of resources and economic aspects of past societies’ lifeways. Seasonality has been stressed out as an important capacity of early human groups to switch (seasonally) from one form of social contract to another, thus providing a flexible social arrangement regarding aspects of social domination, hierarchy, and inequality among various societies around the world (cf. Graeber and Wengrow 2020). Understanding seasonality in the deep past helps us study the development of human social institutions and provides a way to challenge the social evolutionary understanding of inevitable move from egalitarian to socially stratified and class societies.

The overall objectives of the project are as follows: (1) to establish a robust protocol for the study of TCA in red deer, which is often found at prehistoric sites as hunted game, as well as in human dental remains; (2) infer seasonality of occupation of archaeological sites in the chosen case study by determining season-at-death in both red deer and humans; and (3) integrate these seasonality indicators with other types of archaeological data that can disclose key aspects of seasonal scheduling of everyday activities on archaeological sites.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

The training for specific dental histology protocols in making thin sections on archaeological human and red deer teeth specimens as well as on a modern collection of red deer took place at the Bromage Laboratory, i.e. the Hard Tissue Research Unit at the NYU College of Dentistry. At NYU, the Researcher obtained training for specific dental histology protocols in making thin sections, use of microscopy, and, in the summer of 2022, in the use of Scanning Electron Microscopy (SEM) EDS. In the winter of 2021–2022, the Researcher also received training in the use of optical transmitted light microscopy available at SU in DANTE Lab by Prof. E. Cristiani. In 2022, training was also received at the geochemistry laboratory of Goethe University in Frankfurt, Germany in collaboration with Prof. Wolfgang Müller on LA-ICP-MC-MS analyses of enamel from prepared human teeth thin sections. To date, tooth thin sections were prepared, recorded, and analyzed for 60 comparative red deer individuals and 35 archaeological red deer individuals, as well as for 120 archaeological human teeth.

Principal results include the establishment of (1) a new and integrated methodology for the study of tooth cementum annulation (TCA) in red deer and humans with the addition of SEM-EDS elemental analyses of the cementum; and (2) LA-ICP-MC-MS analyses of enamel in human teeth that complement dental histology observations. The obtained results point to (i) pronounced seasonal patterns in the elemental composition of the analyzed red deer specimens in both modern/comparative and archaeologcal specimens; (ii) largely sedentary early life in most of the analyzed humans in the Danube Gorges area during the Early Holocene; and (iii) the existence of individuals buried in this areas in both Mesolithic and Neolithic periods who originated from foreign communities that exhibit pronounced patterns of seasonal movement across different geologies during early life.

The Researcher made six presentations of project results at five different international conferences (SAAs, EAA, and ESHE, 26th Neolithic Seminar in Ljubljana, "First Kings of Europe" conference) and gave two invited talks in New York and Rome. CUSP research has also been mentioned through the Researcher’s participation in the Croatian state TV documentary Hunter-Gatherer shown in the autumn of 2022. The Researcher also gave a number of lectures to students both at NYU and SU in 2021, 2022, and 2023.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

There are three major areas in which progress was made beyond the state of the art:

(1) The use of virtual histology in order to produce reliable estimates of age at death in human teeth explored in the paper by Cerrito et al. 2022 on which the Researcher is a co-author;
(2) Elemental analyses made on red deer cementum using SEM-EDS to explore seasonal fluctuations of different elements deposited in this tissue;
(3) LA-ICP-MC-MS analyses of human enamel coupled with dental histology in order to obtain high-resolution records of human mobility in the early life years and thus infer levels of human mobility/seasonality.

The obtained results improve the methodology of inferring seasonality by using different dental histology approaches and improve the understanding of seasonality in the deep past, especially in the context of complex hunter-gatherer and first farming groups in the area of the Danube Gorges in north-central Balkans.

This research will have potential impact on different stakeholders in the field of prehistoric archaeology. Yet, the conclusions about sedentariness vs. seasonal mobility of various groups in the past can also significantly inform our wider social evolutionary understanding of principles behind the development and functioning of social institutions in human societies more generally, by emphasizing flexible and versatile ways of coping with inter- and intra-group dynamics. In addition, There is a potential for commercialization of obtained research skills and expertise either in the field of wild-life management or in the context of forensic Postmortem Interval (PMI) estimates as well as in better understanding of the nature and causes for the creation of stress lines in both cementum and enamel due to varied physiological events in the course of an individual’s life.

Dusan Boric cutting embedded teeth specimens at the New York University College of Dentistry

Cementum layering on a human tooth specimen from the Mesolithic site of Vlasac, Serbia

Cementum layering on a red deer tooth specimen from the Mesolithic site of Padina, Serbia