Prof. Dr. Doris Breuer

Institut für Planetenforschung, , Rutherfordstrasse 2, D-12489 Berlin, Tel: +49 30-67055301

C4 Summary

The Moon-forming impact is thought to be the last giant collision event that Earth experienced, marking the end of Earth’s accretion process and setting the initial conditions for the subsequent thermochemical evolution of the Earth and the Moon. For both bodies, an early magma ocean is thought to have existed, as a consequence of giant impacts leading to widespread melting. As the geological record of the early evolution history is lacking on Earth only the Moon probably shows relicts of the crystallization of a global or partial magma ocean. The goal of this subproject is to understand how these magma oceans formed and crystallized and how they influenced the thermochemical and tectonic evolution of Earth and Moon. To this end, we aim to constrain the range of plausible thermal conditions after a giant collision that may have resulted in the formation of a global or partial magma ocean on Earth. We will employ well-established numerical models, and we will further develop and adjust them to allow us to simulate giant collisions as big as the Moon-forming event. Using the thermal setting from impact modelling as our input for subsequent detailed fluid and thermodynamical modelling, we intend to quantify dynamics, crystallization, and degassing of a magma ocean in order to constrain the resulting density and temperature profiles and volatile distribution. We will use these models to derive parameterizations, with the help of which we will study the thermochemical evolution of the Moon after its formation, including the phase in which the lunar magma ocean evolved. With these models for both the Earth and the Moon, we will define the thermochemical condition at the time of the late veneer on both bodies. In the end, this subproject aims at providing a model that is consistent with the geochemical signature of the Earth and the Moon.