Hi everyone! We are excited to announce our session at Goldschmidt 2025 (6-11 July) in Prague: “Volatiles and fluids from source to surface”. The session is in Theme 04 (session 04g). Abstract deadline: *February 26, 23h59 (CET/UTC +1) *Submit an abstract and browse sessions at:* conf.goldschmidt.info/goldschmidt/2025/cfp.cgi<http://conf.goldschmidt.info/goldschmidt/2025/cfp.cgi> Conveners: Nancy Hui-Chun Chen, Jamie I. Farquharson, Lauren R Gorojovsky, Richard W Thomas, Manuel Pimenta Silva *Abstract: * The abundances and behaviour of volatile elements during melting, melt transport, and eruption are key to understanding magma generation, melt evolution, and volcanic activity. Fluids, both within magma and as evolved gases and liquids, play a critical role in these processes. The concentrations and oxidation states of major volatiles like CO₂, H₂O, S, and halogens control melting behaviour and the composition of exsolved volcanic gases and fluids. Hydrothermal activity, driven by the interaction of magmatic volatiles with crustal rocks, further influences fluid compositions, mineral formation, and the transport of economically important metals such as Cu, Au, and Sn. The mobility of these metals depends on fluid chemistry, with ligands like Cl⁻ and HS⁻ aiding their transport in hydrothermal systems. At the eruption stage, the release of gases like SO₂ and HCl has significant environmental impacts, affecting climate and ozone levels. In all cases redox is an important control on fluid and melt speciation and the interactions between oxidation states of iron, sulfur and carbon shape the compositions of melts and the fluid phases they release and residual or fractionating solid phases. We invite submissions from diverse disciplines—including experimental, analytical, petrological, and theoretical research - to explore the role of volatiles and fluids in magmatic systems. We encourage studies focusing on the volatile compositions and oxidation states of melts, fluids, and gases; fluid-rock interactions; and the development of innovative experimental, analytical, and computational methods for studying volatiles on Earth. We look forward to seeing you in Prague! Please share this information with interested colleagues. All the best, Nancy, Jamie, Lauren, Richard and Manuel _____________________________ Manuel Pimenta Silva SNSF Postdoctoral Fellow Woods Hole Oceanographic Institution 266 Woods Hole Rd, ML200 Woods Hole, MA 02543