*Apologies for multiple cross postings* Dear colleagues, We would like to draw your attention to our session at Goldschmidt 2021 to be held in Lyon, France on 4-9 July. The conference will be in a hybrid format with a combination of onsite and online meetings. Session 2c: Understanding terrestrial accretion through elemental and isotopic fractionation Keynote speaker: Jabrane Labidi (IPGP) The thermochemical state of Earth’s mantle and core is inherited from processes that took place during the first few hundred million years after condensation of the first solids. High pressures and temperatures related to violent impacts likely gave rise to a magma ocean and resulted in the fractionation of elements and isotopes at a very early stage in Earth’s history through two primary mechanisms; i) core formation and ii) volatilization. Finally, the late delivery of material to the terrestrial planets can be quantified by high precision isotopic studies and elemental ratio evolution through space and time. A suite of high pressure and high temperature devices can reproduce the P-T conditions of Earth and planetary differentiation. These techniques can be coupled with analytical tools from microanalyses (e.g., XRD, Mössbauer) to isotopic measurements. These are complemented by ab initio calculations, through which it is possible to interrogate the extreme conditions typical of planetary formation. In this session, we aim to bring together experimental, geochemical and modelling studies that focus on elemental and isotopic fractionation and can help us to better understand the consequences of accretion and differentiation on the thermal- and compositional evolution of the Earth’s core and mantle, and those of other rocky planets. To that effect we welcome contributions from the fields of experimental petrology, isotope geo/cosmochemistry and numerical modelling to our session. The abstracts submission's deadline is 26 Feb 2021 (23:59 CET). https://2021.goldschmidt.info/goldschmidt/2021/cfp.cgi We look forward to your contributions! With best wishes, Ingrid Blanchard, Raúl Fonseca, Paolo Sossi and Eleanor Jennings