Datensatz

Zusammenfassung

Processes in Earth's deep mantle govern our planet's inner dynamics and impact on surface plate tectonics. As such, a quantitative understanding of the physical and chemical properties of the deep mantle is pivotal to model Earth’s dynamic evolution, including the long-term chemical interactions between mantle and atmosphere that are vital to the development of habitability on Earth, and possibly other planets. While seismic tomography is providing increasingly detailed three-dimensional maps of the lower mantle, the interpretation of tomographic models to elucidate key factors such as mantle geochemical heterogeneity or dynamic mantle flow processes has proven to be highly ambiguous. In part this is due to large gaps in our understanding of material properties at the pressure- and temperature-conditions of the deep mantle. In particular, a limited understanding of the effects of major lower mantle phase and spin transitions on physical properties hampers our ability to converge towards a consistent interpretation of seismic observations. The same phase transitions also play a key role in governing mantle dynamics and need to be accounted for in realistic dynamic models. In this contribution, I will discuss novel experimental findings that help to map phase transitions in the deep mantle, and quantify their impact on physical properties as well as their seismic signature. The experimental findings can guide our interpretation of mantle seismic observables and help to quantify the geodynamic impact of mantle phase transitions, ultimately leading to a holistic picture of Earth’s deep mantle.