Dear Colleagues, We are excited to announce the session 02f “ Experimental and theoretical calibration of isotope fractionation: from core to crust formation<https://conf.goldschmidt.info/goldschmidt/2025/meetingapp.cgi/Session/7403>” at Goldschmidt 2025, Prague (6-11th July) in Theme 2. The keynote talk will be given by Edwin Schauble (University of California, Los Angeles). We welcome contributions that advance our understanding of isotope fractionation through experimental techniques (e.g., gas-mixing furnaces, piston cylinder, multi-anvil studies) and first-principles calculations. Submissions addressing both kinetic and equilibrium processes, as well as their applications to Earth and planetary science, are especially encouraged. We look forward to seeing you in Prague! Please don't hesitate to share this announcement with colleagues who may be interested. Kind regards, Liam, Edith, Ségolène and Remco Abstract deadline: February 26, 23h59 (CET/UTC +1) Submit an abstract and browse sessions at: conf.goldschmidt.info/goldschmidt/2025/cfp.cgi Session abstract: The isotopic compositions of non-traditional elements (e.g. Si, Ca, Ti, Fe, Ni, Zn, Mo, Sn) are an exciting addition to the geochemist’s toolbox and have found a rapidly increasing use in the study of a wide range of high-temperature processes. As such, non-traditional stable isotopes have provided valuable new insights into a range of processes including planetary differentiation and volatile budgets, mantle sources of oceanic basalts, mass transfer in subduction zones, crust formation through time, and mineral-melt reactions. Over the past years, experimental techniques and ab-initio calculations have become crucial to understand with precision the vast array of processes that operate within Earth’s interior. Unlocking the full potential of non-traditional stable isotope data necessitates the robust quantification of the degree of fractionation between the relevant phases of interest (e.g. melts, minerals, fluids, vapours). Isotope fractionation factors from both kinetic and equilibrium processes derived from experimental studies and ab-initio calculations provide the framework with which to effectively rationalise and model natural isotope data. For instance, further experimental constraints on kinetically induced isotope fractionation of volatile elements could help tackle the question of volatile loss during planetary formation and giant impacts. This session provides a podium for the exciting vistas offered through experimental and theoretical calibrations of isotope fractionation. We welcome a wide range of contributions that aim to further our understanding of stable isotope fractionation at high-temperature using experimental techniques (e.g. gas-mixing furnace, piston cylinder, multi-anvil studies) or first-principles calculations. Conveners: Liam Hoare (University of Tuebingen) Edith Kubik (Bayerisches Geoinstitut) Ségolène Rabin (AMGC, Vrije Universiteit Brussel) Remco C Hin (CNR-IGAG, Italy)