IAP-24-027

Holocene Antarctic Peninsula Tephrochronology (HolAP-Tephra): Using Antarctic Peninsula ice core records to assess Holocene volcanic activity climate impacts.

Volcanic eruptions emit large volumes of aerosols into the atmosphere, which can impact the total solar radiation perceived at Earth’s surface, potentially creating long-lasting climate variations. Ice cores are faithful recorders of past climate change and volcanic activity. Ice core high-precision chronologies enable us to analyse volcanic-sourced aerosols and accurately reconstruct past volcanic activity, while directly assessing the relationship between the timing and magnitude of eruptions and their corresponding climatic impact. Previous studies analysing Antarctic ice cores for reconstructing past volcanic activity have concentrated on studying solely volcanic sulphate enhancements preserved in ice layers (Cole-Dai et al., 2021) or the volcanic microparticle (cryptotephra) content from targeted volcanic events based on large sulphate and microparticle concentration enhancements (Abbott et al., 2024). To date, no research has performed a comprehensive study of cryptotephra preserved in Antarctic ice core layers throughout the Holocene. This project aims to take a step forward in the study of past volcanism by studying the cryptotephras preserved in Antarctic ice layers, first at decadal-to-centennial resolution, covering the whole Holocene, to increase the temporal resolution over targeted periods. This approach will likely reveal many previously unknown eruptions from a wide variety of sources, including elusive Antarctic volcanism (Tetzner et al., 2021), providing important insights into the impacts of volcanism on climate. The successful applicant will join the ice core team at the British Antarctic Survey (BAS) to work on an array of existing ice core records from the BAS ice core archive. The successful candidate will also have the exciting opportunity to complement its results with ice core samples obtained from the new NERC-funded REWIND project (to be drilled during 2024-26) that will collect the longest and oldest ice core ever recovered from the Antarctic Peninsula. The PhD student will have the unique opportunity to join the BAS ice core team in the processing and analysis of the REWIND ice core in BAS’s ice core laboratories. The student will also join the St Andrews Volcanic Eruptions and Impacts (StA-VEI) Group at the University of St Andrews (https://www.st-andrews.ac.uk/earth-sciences/research/centres/sta-vei/) who are developing promising new approaches for ice-core cryptotephra research (Innes et al. 2024).

The research methods employed during this project will include:

(1) Processing ice core samples inside BAS’s cold storage facilities and the analysis of ice core impurities using BAS’s continuous flow analysis (CFA) system (Grieman et al., 2022). Ice core CFA analyses, including liquid conductivity, ion chromatography (sulphate), and microparticle concentrations, will be used to identify and target potential volcanic horizons.

(2) Cryptotephra mounting, identification using optical and scanning electron microscopy (SEM), and chemical analyses (including laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and electron microprobe analysis using wavelength-dispersive spectrometry (EMPA-WDS) will be performed following the methods outlined in Abbott et al. (2024), and Innes et al. (2024).

Year 1

The student will spend the first half of the year working on characterising and analysing existing data from last-millennia large eruptions preserved in ice cores from the BAS ice core archive. During the second half of the first year, the student will have the possibility to work alongside the BAS ice core team processing and analysing samples from the newly drilled REWIND project, using BAS’s continuous flow analysis system. By the end of the first year, the student will be encouraged to attend and actively participate in the International Partnership in Ice Core Sciences conference (IPICS 2026).

Year 2

The student will spend the first half of the second year working on the data generated from BAS ice core archive samples to identify large volcanic eruptions over the Holocene and target specific horizons for cryptotephra studies. The second half of the second year will be focused on the cryptotephra analyses of previously targeted horizons (sample preparation, microscopy and microanalysis at St Andrews cryptotephra facilities).

Year 3

Year three will be focused on consolidating the cryptotephra results obtained in the previous year to generate a comprehensive Antarctic tephrochronology covering the whole Holocene. Based on this detailed tephrochronology, the student will assess the magnitude, frequency and origin of large Holocene volcanic eruptions and explore their potential climate impacts using other available ice core data and paleoclimate records. During year three, the student will be encouraged to present the main findings of the PhD project at a large international conference (e.g. EGU-2028).

Year 3.5

During the last six months of the project, the student will be focused on PhD thesis writing

The student will be trained in ice core processing and analysis techniques at the British Antarctic Survey (BAS), and cryptotephra sample preparation and analyses at the University of St Andrews (sample mounting for optical and electronic microscopy (SEM), EPMA and LA-ICP-MS analyses). The student will develop skills in analytical methods, reporting, problem-solving and critical thinking, experiment management and teamwork.