Beyond EPICA : Impurities Continuous Flow Analysis campaign launched in late August at British Antarctic Survey

On 26 August, the first continuous flow analysis (CFA) campaign of Beyond EPICA ice began, which will enable us to reconstruct climate variations over at least the last 1.2 million years.

The team participating in the launch of the CFA campaign to measure the Beyond EPICA ice core at the British Antarctic Survey. Around thirty people will take turns over approximately seven weeks, from the BAS and the University of Cambridge, as well as from the Universities of Bern, Heidelberg, Saint Andrews, Swansea, Venice, the AWI in Bremerhaven, and the LSCE.

The ice drilled in the frame of the European project Beyond Epica Oldest Ice during the 2024–2025 season at Little Dome C was brought back to Europe at the end of spring and then cut in Bremerhaven in June and July. In addition to samples sent to each project partner for discrete analysis, one-metre-long bars were cut for continuous flow analysis: in a cold room, the bars are placed vertically on a melt head heated to around ten degrees to slowly melt the ice: the water is then sent outside the cold room to a maximum number of analysis instruments.

The main objective of this first CFA campaign is to measure impurities, and it is coordinated by the British Antarctic Survey (BAS) in Cambridge. In addition to instruments from the BAS and the University of Cambridge, many partner teams in the project have deployed additional instruments or sample collectors, some in a clean room, for subsequent analysis. The aim is to make the best possible use of all available meltwater. A device specially developed for this campaign has even been installed by the Heidelberg team to recover the air from bubbles trapped in the ice: the aim is to measure ⁸¹Kr (half-life of 229 kyrs) for radiometric dating.

*Ice bar on the melt head in the cold room.*

*View of the laboratory housing the CFA master computer and the different instruments.*

The online instruments for this CFA campaign include: conductivity probes, colourimetric measurement of Ca²⁺ and NH₄⁺, two fast ion chromatography units for anions, an ICP-MS, an ICP-OES, an Abakus and two SPES units (Single Particle Extinction and Scattering) to quantify and characterise dust, and a Picarro laser analyser to measure water isotopes. Discrete samples are collected for subsequent microbiological, diatom, tephra, or more specific chemical analyses.

Water isotope measurements are the responsibility of the project’s ‘Water Isotopes’ consortium, which brings together teams from the LSCE, AWI (Germany), Venice, Copenhagen and Bergen. On behalf of the LSCE, Elise Fourré participated in the installation of the equipment for a week in early July and in the launch of the campaign at the end of August, before being relieved by other colleagues from the consortium.

The aim of this CFA campaign is to measure the ice between 2,400 and 2,592 metres deep, at a rate of 8 metres per day at cruising speed. In order to supply all the instruments with water at sufficient resolution, the melting speed is 1.5 cm/min, i.e. nearly 9 hours of measurement per day, preceded and followed by instrument calibrations.

A second CFA measurement campaign will take place in the first quarter of 2026, coordinated by the University of Copenhagen, followed by another in Grenoble coordinated by the IGE in early 2027, with the main objective of analysing the composition of air bubbles. For these measurements, the melting speed must be faster, at least 3 cm/min. The LSCE GLACIO team will also be involved, measuring δ¹⁸O of O₂.