LPL Colloquium: Dr. Samuel Crossley

Oxidized Planetary Differentiation


3:45 to 4:45 p.m., April 16, 2024


Dr. Samuel Crossley
University of Arizona, Lunar and Planetary Laboratory

The familiar layered structure of planetary interiors formed as their initial components melted and segregated to form a core, mantle, and crust. In detail, this process of planetary differentiation was much more complex. Cosmochemical characteristics inherited from different regions of the solar system led to divergent igneous processes that are manifested in the compositional variety of differentiated meteorites.      

In this talk, I will give an overview of how oxidized meteorite parent bodies from the inner solar system melted and diverged from the evolutionary trajectories of other planetary materials. These findings culminate from a coordinated series of investigations utilizing meteoritics, experimental petrology, trace element geochemistry, and remote sensing. Our results demonstrate that melting and differentiation began at lower temperatures via distinct physical pathways due to high concentrations of oxygen and sulfur, leading to the formation of a sulfide core. This process left diagnostic geochemical signatures in the residual mineralogies of differentiated meteorites. Corresponding mineral assemblages are resolvable with remote sensing techniques and dominate the population of olivine-rich asteroids in the Main Belt. Collectively, this implies that sulfide core formation was a common process in oxidized regions of the of the early solar system and carries significant implications for our understanding of planetary differentiation.   

View Dr. Crossley's Lecture