Dr. Aaron Bell
CU Boulder

Academic host: Kevin Mahan

Topic: Angrites – Exploring the Origins of the Most Unusual Basalts in the Solar System

Abstract: Angrites are a group of rare and geochemically unique achondritic meteorites that represent crystallized silicate liquids. Angritic meteorites are broadly classified as critically silica-undersaturated “basalts” which are characterized by their ancient crystallization ages (i.e., 4.563 Ga) and the unusual compositions of phases in their mineral assemblages. In the broadest context, angrites pose challenges to our current understanding of the compositional and redox diversity of protoplanets that were present in the early inner solar system.  Although numerous hypotheses have been proposed to account for the petrogenesis of angrites, there is little consensus on their origins, and many fundamental questions about these meteorites remain unanswered. In this talk I will present the results from recent phase equilibrium experiments, thermodynamic calculations, and Cr K-edge XANES measurements in an effort shed new light on some of the most vexing questions about the origins of angrites and their relationship to other planetary and asteroidal basalts.