Coordinating Analytical Strengths for LA-ICP-MS Analysis of the Beyond EPICA Core

The "Beyond EPICA Oldest Ice Core" (BE-OIC) collaboration has successfully recovered the Antarctic ice core BELDC (Beyond EPICA Little Dome C) reaching back at least 1.2 million years (Stenni et al., 2025). This record is expected to provide a crucial missing link for understanding the cause of the Mid-Pleistocene Transition. However, the extreme thinning of the deepest ice layers compresses more than 20k years in one meter, and thus calls for analysis at high spatial resolution going hand-in-hand with a rigorous assessment of stratigraphic integrity. For aerosol-related chemical impurities, post-depositional processes, such as diffusion, grain growth displacement, and geochemical reactions, are known to pose significant challenges for record preservation in deep ice.

Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) offers decisive advantages in this context by analysing the surface of solid ice samples at the micrometer scale (in the order of 1−100 μm). To fully exploit its potential for the BE-OIC project and to coordinate the LA-ICP-MS analysis of the BELDC deep sections, a dedicated "Laser Ablation Focus Group" has been established with members of AWI Bremerhaven and the Universities of Frankfurt, Venice and Cambrige. Here we present the first results of an ongoing "round robin" experiment designed to integrate the strengths of our different analytical systems. This intercomparison study utilizes shallow BELDC sections, covering both glacial and interglacial ice, which are currently analysed by two newly established systems: a broadband 2D mapping setup (AWI Bremerhaven; Bohleber et al., 2025) recently upgraded with a 33 cm cryogenic chamber for high throughput, and a dual-wavelength (157 & 193 nm) system optimized for high ablation efficiency of ice including a custom-designed cryo-holder (Uni Frankfurt; Erhardt et al. 2025).

By extending this inter-laboratory comparison to further LA-ICP-MS facilities of the focus group, we aim to establish a standardized framework for the BELDC deep-ice analysis and possibly also other future ice core projects. At the same time, our results provide the first LA-ICP-MS datasets for the BELDC core and indicate how these high resolution impurity datasets can be integrated with other methods, such as Continuous Flow Analysis (CFA). Ultimately, this collaborative effort aims to maximize the scientific output of LA-ICP-MS for the BE-OIC project by contributing to the most robust interpretation of this unique paleoclimate archive.

 

References

Bohleber, P., Stoll, N., Larkman, P., Rhodes, R. H., & Clases, D. (2025). New evidence on the microstructural localization of sulfur and chlorine in polar ice cores with implications for impurity diffusion. The Cryosphere, 19(11), 5485-5498. https://doi.org/10.5194/tc-19-5485-2025

Erhardt, T., Norris, C. A., Rittberger, R., Shelley, M., Kutzschbach, M., Marko, L., ... & Müller, W. (2025). Rationale, design and initial performance of a dual-wavelength (157 & 193 nm) cryo-LA-ICP-MS/MS system. Journal of Analytical Atomic Spectrometry, 40(10), 2857-2869. https://doi.org/10.1039/D5JA00090D

Stenni, B., Wilhelms, F., Westhoff, J., Alemany, O., Hansen, S., Dahl-Jensen, D., ... & Zannoni, D. (2025). The Beyond EPICA–Oldest Ice Core Project. European Association of Geochemistry. Goldschmidt 2025 Abstract. https://doi.org/10.7185/gold2025.29931