Natasha Keeley

Biography

In 2023, I graduated from the University of Leeds with First-Class Honours in Geological Sciences (Integrated Master’s). During my final year, I specialised in volcanology, completing a geological mapping dissertation in the Lake District and a geochemical research project on Volcán Colima (Mexico), investigating deposits from both explosive and effusive eruptions. I also undertook a four-week summer research placement monitoring Teide (Tenerife), where I collected volcanic gas samples and gas flux data to support ongoing hazard assessment.

I am now undertaking a PhD at Keele University under the supervision of Dr Ralf Gertisser, Dr Elliot Carter, and Dr Chiara M. Petrone (Natural History Museum, London). My research uses core deposits recovered during International Ocean Discovery Program (IODP) Expedition 398 to the Southern Aegean Volcanic Arc to investigate post-caldera magmatic system evolution at Santorini following the Late Bronze Age (Minoan) caldera-forming eruption. I also examine the timescales of magmatic processes prior to the large-magnitude, shallow-submarine eruptions at Santorini (726 CE) and Kolumbo (1650 CE).

I currently serve as the Student Representative for the Volcanic and Magmatic Studies Group (VMSG).

Research and scholarship

PhD Title - Magmatic processes and timescales of post-Bronze Age eruptions in the Christiana-Santorini-Kolumbo Volcanic Field, Greece

From December 2022 to February 2023, International Ocean Discovery Program (IODP) Expedition 398 to the Southern Aegean Volcanic Arc drilled 12 sites across the rift basin hosting the Christiana-Santorini-Kolumbo Volcanic Field and the volcano-sedimentary succession within Santorini caldera. Drilling beneath the seafloor recovered numerous pumice and ash layers representing volcanic eruptions, including deposits known from the onland record as well as previously unidentified events with no preserved subaerial outcrops. These deposits document minor to large-magnitude submarine to subaerial explosive eruptions from Christiana, Santorini, and Kolumbo.

This project investigates tephra from identified eruption units recovered in the IODP drill cores. The focus is on post-Minoan eruptions preserved within cores drilled inside the Santorini caldera basins (Sites U1594–U1597), as well as the 1650 CE Kolumbo eruption identified in cores recovered adjacent to Kolumbo Central Volcano (Sites U1590 and U1593) and within the Anhydros Basin (Site U1589).

Using an integrated petrological, volcanological, and geochemical approach, and in collaboration with project partners in the UK, France, Germany, and the USA, the project aims to:

1. Constrain magma storage conditions prior to identified post-Minoan eruptions.
2. Characterise pre-eruptive magmatic processes of post-Minoan eruptions.
3. Quantify the timescales of magmatic processes preceding the large-magnitude, shallow-submarine Santorini eruption of 726 CE and identify eruption triggers.
4. Correlate submarine post-Minoan deposits with onland sequences from the Kameni Islands.
5. Evaluate the evolution of the post-Minoan magma system following the caldera-forming eruption, characterising the transition from caldera-forming to post-caldera activity.
6. Quantify the timescales of magmatic processes preceding the large-magnitude, shallow-submarine Kolumbo eruption of 1650 CE and identify eruption triggers.
7. Assess the hazards associated with these eruptions and their implications for future risk in Santorini and the eastern Mediterranean.

The PhD project is fully integrated within the IODP Expedition 398 post-cruise research programme. Sample preparation is conducted at Keele University. Crystal and glass compositions are analysed using Electron Microprobe and LA-ICP-MS at the Natural History Museum (London) in collaboration with Dr Chiara Petrone and Dr Alejandro Cortes-Calderon. Whole-rock major and trace element concentrations (ICP-OES and ICP-MS) were analysed at Actlabs, Canada.