The Archaean Earth - Coupling between geodynamics and 3D climate modelling

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The Archaean (3.8 - 2.5 Gyrs) is a geological eon that brought with it great transitions in the development of the habitable Earth. The atmosphere composition probably changed drastically: To explain the faint young Sun paradox at the beginning of the Archaean, an atmosphere with large amounts of greenhouse gases are needed. At the end, the atmosphere contained roughly present day atmospheric levels of greenhouse gases and started to accumulate free oxygen. The geological processes also changed drastically: Plate tectonics probably developed during the Archaean and influenced atmosphere composition via an early carbon cycle. The first continental crust that survived until today also formed and grew during the Archaean. The exposed continental crust influences the atmosphere composition, e.g. by acting as sink for carbon dioxide and oxygen via weathering processes. In this project, we will couple for the first time a 3D/1D climate and a 2D state-of-the-art mantle convection model to investigate the properties of the atmosphere (composition and extent), surface temperatures and different onset times for plate tectonics during the Archaean. We will thus address the young Sun paradox and investigate the coupled evolution of the Archaean atmosphere and geodynamics - providing new context for geological and geochemical data - from early to late Archaean. The model will incorporate rigorously and physically motivated constraints together with geological and geochemical evidence for outgassing rates, ocean temperatures, Archaean atmosphere composition, plate tectonics on-set and crustal growth during the Archaean derived by collaborators in the project "Building a Habitable Earth".