Pallasite meteorites and preserved planetary mantles: a multiscale computational and petrological study of planetary evolution

Pallasite meteorites are enigmatic mixtures of olivine and metal, from the mantles of some of the earliest forming and differentiating planetesimals in the Solar System. These fragments of planetary building blocks can provide a window into the deep interior of early Solar System planetesimals, and can reveal insights into planetary differentiation, core formation and evolution, and subsequent catastrophic breakup. Pallasite samples are thought to form via the violent mixing of two impacting planetary bodies, but
many of the details of this process are still not understood. In this thesis, I apply a multidisciplinary approach to improve our understanding of planetesimal evolution via the investigation of pallasite meteorites, combining numerical modelling and analytical petrology, at a range of temporal and spatial scales.
Specifically, I address the until-now irreconcilable metal and olivine cooling rates recorded in pallasite samples, propose constraints for the geometry of the pallasite parent body and the region of metal and olivine mixing, and suggest novel mechanisms for metal propagation into the pallasite parent body mantle with implications for the preservation of planetesimal mantles and “The Missing Mantle Problem”. This work, while focused on a specific meteorite sub-group, has implications beyond just pallasite samples, which I highlight throughout the thesis.