XRONOS development in 2022

By Joe Roe, 2022-12-20 01:00:00 UTC

There has been a lot of behind-the-scenes work on XRONOS this year. Our primary focused has been building a back-end interface for importing and curating data. This will be the foundation of more visible changes next year, when we will start a push to significantly improve the accuracy and consistency of the database.

This has also brought several visible improvements to the XRONOS web front-end, some of which you might already have noticed!

Streamlined data model

Perhaps the biggest behind-the-scenes change we’ve made this year is the introduction of a new, streamlined data model. We’ve simplified the association between chronometric information and archaeological context, so for example you’ll now see a single type ‘typological date’ where before we had ‘periods’, ‘typochronological units’, and ‘ecochronological units’. Both radiocarbon and typological dates are associated with an archaeological site via ‘sample’ and ‘context’ objects, describing the properties of, respectively, the physical object and the archaeological context the date relates to. Sites can have any number of radiocarbon and typological dates and, in the future, other types of chronometric information like dendro dates.

The new data model also brings better support for bibliographic references, which can be attached to to any type of date or directly to a site. We also now track all changes made to a record since it was created, leaving a transparent record of when and why data was altered. You can preview both these new features on the site record for ʿAyn Qasiyya, for example.

The API v1 that uses the old schema is still available and will be maintained for backwards compatibility for the foreseeable future. However, in the coming months it will be deprecated in favour of a new API v2, which will take greater advantage of the streamlined data model.

Continued data imports

At the beginning a December we significantly expanded the database by re-importing the source databases indexed by the R package c14bazAAR.

Source databases imported into XRONOS as of December 2022:

Source database Reference Licence # records
KITE East Africa Courtney Mustaphi, Colin, 2016, “Radiocarbon dates from eastern Africa in the CARD2.0 format”,, Harvard Dataverse, V5 Public Domain (CC0 1.0) 793
BDA Perrin, Thomas (2021) «BDA – Base de Données Archéologiques» [Dataset] NAKALA. Open Database License 6910
AgriChange Martínez-Grau, Héctor, Morell-Rovira, Berta, & Antolín, Ferran. (2020). Radiocarbon dates associated to Neolithic contexts (ca. 5900 – 2000 cal BC) from the northwestern Mediterranean Arch to the High Rhine area [Data set]. In Journal of Open Archaeology Data (Vol. 9, Number 1, pp. 1–10). Zenodo.   3617
p3k14c Bird, D., Miranda, L., Vander Linden, M. et al. p3k14c, a synthetic global database of archaeological radiocarbon dates. Sci Data 9, 27 (2022).   179689
SARD Loftus, E., Mitchell, P., & Ramsey, C. (2019). An archaeological radiocarbon database for southern Africa. Antiquity, 93(370), 870-885. doi:10.15184/aqy.2019.75   2728
AIDA Palmisano, A., Bevan, A., Kabelindde, A., Roberts, N., & Shennan, S., 2022. “AIDA: Archive of Italian radiocarbon DAtes”, version 5.0 (9 April 2022): CC-BY 4.0 4629
NERD Palmisano, A., Bevan, A., Lawrence, D., & Shennan, S., 2022. NERD: Near East Radiocarbon Dates, version 6.0 (23 September 2022): CC-BY 4.0 11072
14SEA Reingruber, A., and Thissen, L. (2017). The 14SEA Project: A 14C database for Southeast Europe and Anatolia (10,000–3000 calBC). Updated 2017-01-31.   3025
aDRAC Seidensticker, D. & W. Hubau (2021), ‘aDRAC. Archive des datations radiocarbones d’Afrique centrale’, Version 2.0. Open Database License 1916
RADON Martin Hinz, Martin Furholt, Johannes Müller, Dirk Raetzel-Fabian, Christoph Rinne, Karl-Göran Sjögren, Hans-Peter Wotzka, RADON – Radiocarbon dates online 2012. Central European database of 14C dates for the Neolithic and Early Bronze Age., 2012, 1-4. CC-BY 3.0 20325
RADON-B Jutta Kneisel, Martin Hinz, and Christoph Rinne. 2013. RADON-B – Database for European 14C dates for the Bronze and Early Iron Age. CC-BY 3.0 11048
Katsianis et al. 2020 Katsianis, Markos; Bevan, Andrew; Styliaras, Giorgos; Maniatis, Yannis (2020): Dataset for: An Aegean history and archaeology written through radiocarbon dates. University College London. Dataset. CC BY 4.0 3159
CalPal Weninger, B. 2020. CalPal Archaeological 14C-Database. 49834  
EUROEVOL Manning, K; Timpson, A; Colledge, S; Crema, E; Shennan, S; (2015) The Cultural Evolution of Neolithic Europe. EUROEVOL Dataset. Public Domain (CC0 1.0) 14053
IRDD Chapple, R. M. 2018 ‘Catalogue of Radiocarbon Determinations & Dendrochronology Dates (March 2018 Release)’. Oculus Obscura Press, Belfast.   10665
caribbean-14C Riris, Phil. 2021. carribean-14C: A compilation of 2147 anthropogenic radiocarbon (14C) dates for the Caribbean region from 504 sites across 57 islands. Public Domain (CC0 1.0) 2147
AustArch Alan Williams, Sean Ulm (2014) AustArch: A Database of 14C and Luminescence Ages from Archaeological Sites in Australia [data-set]. York: Archaeology Data Service [distributor] ADS Terms of Use and Access 5044
CONTEXT Schyle, D. & Böhner, U. 2006. Near Eastern radiocarbon CONTEXT database.   2874
EUBAR CAPUZZO G, BOARETTO E, BARCELÓ JA. 2014. EUBAR: A database of 14C measurements for the European Bronze Age. A Bayesian analysis of 14C-dated archaeological contexts from Northern Italy and Southern France. Radiocarbon 56(2):851-69.   1785
rxpand de Souza, Jonas Gregorio. 2021. rxpand: Radiocarbon dates for the spread of farming and ceramics in tropical South America. MIT License 2794
Crema & Kobayashi 2020 Crema, E.R., Kobayashi, K., 2020. A multi-proxy inference of Jōmon population dynamics using bayesian phase models, residential data, and summed probability distribution of 14C dates. Journal of Archaeological Science 117, 105136. DOI:   2132
Palmisano et al. 2017 Palmisano, A; Bevan, A; Shennan, S; (2017) Regional Demographic Trends and Settlement Patterns in Central Italy: Archaeological Sites and Radiocarbon Dates. [Dataset]. UCL Institute of Archaeology: London, UK. doi:10.14324/000.ds.1575442   816
PACEA d’Errico, Franceso; Banks, William E.; Vanhaeren, Marian; Laroulandie, Véronique; Langlais, Mathieu. 2011. PACEA Geo-Referenced Radiocarbon Database. PaleoAnthropology 2011: 1–12. doi:10.4207/PA.2011.ART40   6020
MesoRAD Hoggarth, J.A., Ebert, C.E. and Castelazo-Calva, V.E., 2021. MesoRAD: A New Radiocarbon Data Set for Archaeological Research in Mesoamerica. Journal of Open Archaeology Data, 9, p.10. DOI: CC BY 4.0 1528
MedAfriCarbon Lucarini, Giulio, Wilkinson, Toby, Crema, Enrico R., Palombini, Augusto, Bevan, Andrew, & Broodbank, Cyprian. (2020). The MedAfriCarbon radiocarbon database and web application. Archaeological dynamics in Mediterranean Africa, ca. 9600-700 BC [Data set]. In Journal of Open Archaeology Data (1.0.3). Zenodo. CC BY 4.0 1587

This brings us to a total of 73,429 site records, 350,190 radiocarbon dates, and 138,176 typological dates. Many of these records are different versions of same site or date, however. One of our many priorities in 2023 will therefore be to apply systems for identifying duplicate records and reconcile variant data from different sources.

Refreshed web interface

We have also being refresh the front-end user experience in step with improvements to the back end. The data browser, combining map and data views, has been overhauled and streamlined to cope with the volume of data we now have – though this remains a challenge! Similarly we have also given a facelift to the home page, site and radiocarbon date views, and about pages.

Project updates

Earlier this year we welcomed Setareh Ebrahimiabareghi to the team. Setareh is a specialist in Iranian prehistory and has been working on improving XRONOS’ coverage of Southwest and Central Asia, adding previously difficult-to-access dates from the Persian and Pashto literature, as well as comprehensively reviewing our existing records for accuracy and completeness.

We are also very grateful to Tomasz Chmielewski‬, who has volunteered his time to a similar review and expansion of our coverage of Poland, Hungary, Slovakia and the Czech Republic.

In September we presented a talk about XRONOS at the European Association of Archaeologists (EAA) annual meeting in Budapest (virtually), discussing the aims of the project and the challenges we have faced with regard to the practical implementation, sustainability, and ethics of open data infrastructure in archaeology. We’ll present further results at Digital Archaeology Bern, a colloquium taking place here at the Institute for Archaeological Sciences next February.