This PhD project at The University of Manchester investigates the origin and evolution of halogens (Cl, Br, I) in magmas at Mt Etna volcano, Sicily, with a focus on understanding volatile recycling in subduction zones. Subduction zones are key sites for magma generation, where volatiles from the sinking oceanic slab induce melting in the mantle wedge, producing volatile-rich and oxidised magmas. These magmas, when erupted through volcanic arcs, are highly explosive and have significant impacts on both local populations and global climate through their gas emissions. The chemical and isotopic signatures of these emissions provide insights into the recycling of slab-derived materials and the evolution of Earth's atmosphere over geological time. The project aims to clarify which volatiles are released from the subducting slab, under what conditions, and how efficiently they are recycled to the surface. Halogens are particularly informative, as their relative abundances in magmas can indicate the contributions of different recycled slab components, such as sediments, altered basaltic crust, and serpentinised peridotite. The research will begin with the analysis of olivine crystals from recent basaltic eruptions at Mt Etna, where recycled slab influence has been detected. The student will conduct comprehensive geochemical and petrographic characterisation of eruption deposits, analysing volatile and trace element contents in olivine-hosted melt inclusions using SIMS and laser ICP-MS, and fluid inclusions using FTIR and Raman microscopy. Further, the olivine crystals will be subjected to irradiation and in vacuo crushing or laser heating, followed by neutron irradiation noble gas mass spectrometry to determine halogen abundances. The study will compare recent slab-influenced lavas with older deposits from Etna’s Holocene history to assess changes in recycled slab influence over time. The project offers flexibility for the student to pursue additional fieldwork or comparative studies in other subduction zones. The Department of Earth and Environmental Sciences at Manchester provides unique analytical facilities for halogen measurement at ppb levels. The position is fully funded for 3.5 years, with candidates nominated for faculty funding and access to a range of scholarships and studentships for both UK and international students. Applicants should have at least a 2.1 honours degree or a master’s in a relevant science or engineering discipline. The application process requires an online submission with supporting documents, including transcripts, CV, a motivation statement, and referee contact details. The university values diversity and supports flexible study arrangements. The application deadline is 13th March 2026, with an earlier funding deadline on 19th December 2025. Early application is recommended as the advert may close before the deadline.