Tag: ta2.16

21-EPN-FT1-028 – Integrated aDNA, Sr-O-C isotope data and 14C dates to link human individuals to Roman military units

Visit by Lisette Kootker, Vrie University Amsterdam (Netherlands), to TA2 Facility 16 – Carbon-14 Dating AMS Laboratory (Hungary).
Dates of visit: 28 November – 02 December 2022.

Report Summary: The lower German limes, the most northern frontier of the Roman Empire on mainland Europe, was the earliest linear frontier of the Roman Empire. Where the Lower German limes ends in the North Sea, the unique Roman cemetery of Valkenburg Marktveld was excavated that plays a key role in understanding the population dynamics in a Roman borderland and coastal landscape. In addition to our current biomolecular research, AMS radiocarbon dates were proposed of 29 adult individuals who were subjected to isotope and aDNA studies with the aim to establish an essential and reliable dating framework that will contribute to the human story and understanding the human history at the Marktveld site.

Prior to the Europlanet TA visit at the Isotoptech Zrt. AMS laboratory, collagen was successfully extracted from 27 individuals. During the visit, our team had the opportunity to learn how the MICADAS system applied to analyse the collagen samples was operated. The calibrated ¹⁴C dates range between 343 BCE to 244 CE. Additional δ¹³C and δ¹⁵N will be used to evaluate the collagen quality and possible impact of reservoir effects. Preliminary analysis shows the presence of four groups: 1) pre-Roman; 2) 100 BCE – 60 CE; 3) up to 125 CE, and finally; 4) and younger than 125 BCE. The associated ⁸⁷Sr/⁸⁶Sr show slightly higher mean and more variation in the last two groups than the first two (0.7102 ± 0.0010 vs. 0.7096 ± 0.0009). The ¹⁴C data will be reposited in IsoArc

20-EPN2-118: Solar activity studies around 660 BC and 800 BC by radiocarbon analysis of annual tree rings using accelerator mass spectrometry

Visit by Ivan Kontul, Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava (Slovakia), to TA2 Facility 16 – Carbon-14 Dating AMS Laboratory (Hungary).
Dates of visit: 29 August – 09 September 2022

Report Summary: Several relatively rapid spikes in radiocarbon levels have recently been found by radiocarbon analysis of tree rings, most notably the 774-775 AD increase. Additional measurements confirmed this C-14 spike to be a global event and the evaluation of radiocarbon data showed that these excursions could be connected to rapid changes in solar activity. Similar changes in radiocarbon levels have been observed in tree-ring samples from USA and Germany around 660 BC and tree rings from USA around 800 BC. The measurement of annual growth rings from other parts of the world could contribute to the research of rapid changes in past radiocarbon levels and their connection to solar activity.

During this Europlanet visit, we used accelerator mass spectrometry to measure radiocarbon content of dendrochronologically dated tree rings from Yamal peninsula in Siberia covering the periods 836-779 BC and 671-651 BC. The measurements of tree rings from these periods show that the 660 BC and 800 BC excursions are present in tree-ring record from a different part of the world as previous measurements (Germany, Poland and Japan for 660 BC; USA and Japan for 800 BC), and it indicates the events causing these spikes have indeed a global character.

20-EPN2-018: Structure of the radiocarbon calibration curve around Miyake effect in 660 BC, AD 775 and AD 994

Visit by Andrzej Rakowski, Silesian University of Technology (Poland) to TA2 Facility 16 – Carbon-14 Dating AMS Laboratory (Hungary).
Dates of visit: 6-26 July 2022

Report Summary: Evidence of a rapid increase in the radiocarbon concentration of the tree rings for the year 775 CE was initially presented by Miyake et al in 2012 (henceforth called M12). Since then, other events similar to the M12 have been confirmed for different periods. This project aims to provide new information about the increase in concentration of radiocarbon in the period of abrupt solar activity. For the study we have chosen the periods in XI^th and XIII^th century CE and in VII^th century BCE, in which increase of radiocarbon concentration was noted. The samples have been collected from dendro-chronologically dated trees, and the annual rings has been extracted for measurement.

During the Europlanet TA visit in the Isotoptech Zrt. AMS laboratory, all the samples were prepared to be measured using MICADAS AMS system. Each set of measurement was accompanying with standardsamples (of known radiocarbon concentration) to control the quality of the measurement. To obtain high precision (<2 ‰) the measurement time was extended. The results show occurrence of Miyake events in analyzing periods. For the analyzing period in VIIth century we were able to determinate the occurrence during the year, by dividing the annual ring into three parts early-wood, early-late wood and late wood. During the TA visit we have possibility to learn about the procedures used in the laboratory to prepare samples (of different kinds) for radiocarbon measurement using AMS system. We had a fruitful discussion on possible future cooperation, including joint submission of a research project proposal.

Read the full scientific report, with kind permission by Andrzej Zbigniew Rakowski.

20-EPN2-025: Determining the C-14 ages of offshore groundwater by analysing fluid samples with small quantities

Visit by Nai-Chen Chen, University of Stockholm (Sweden) to TA2 Facility 16 – Carbon-14 Dating AMS Laboratory (Hungary).
Dates of visit: 14-25 March 2022

Report Summary: Submarine groundwater discharge (SGD) has been shown to be an important mechanism in transporting solutes from the terrestrial to the marine environment. Despite being a well-documented process, our knowledge about the timing of offshore groundwater emplacement is extremely scarce. We aim to develop an age-dependent numerical model in our study area to investigate the relationship between SGD and the carbon cycle, whereby the obtained ¹⁴C age of the groundwater is used as a constraint. Our goal is to analyze all the carbon pools present in our cores (i.e. TIC, TOC, DIC and CH₄) for ¹⁴C, so that we can correct for possible interference with the ¹⁴C-DIC signal (used for groundwater age). This is a challenge however, as the carbon content for some of these samples is extremely low.

During this two-week visit, we not only learned about the ¹⁴C preparation methods and operation of Accelerator Mass Spectrometry (AMS), but also discussed and exchanged ideas with Isotoptech AMS C-14 group scientists. Preliminary ¹⁴C results indicate that ¹⁴C depleted DIC is observed closer to the sediment-water interface for cores with anticipated SGD. This can be explained by the advective upwards transport of older groundwater. The discrepancy between the TIC and TOC ¹⁴C content at similar core depths was found to be very large, indicating that these carbon pools are affected by different processes. This mismatch might be a result of the precipitation of authigenic carbonates or microbial activity.