Experimental Constraints on Melting Processes in the Earth and Small Rocky Bodies

Abstract

The compositional and thermal evolution of rocky bodies in the Solar System is determined by the melt generation and crystallization processes in their interiors. This thesis investigates large-scale igneous processes in the Earth, the Moon, and the Angrite Parent Body using a multidisciplinary approach that integrates high-pressure experiments, geochemical analysis, and petrologic modeling. In Chapter 1, I examine the mantle source lithology of Hawaiian pre-shield tholeiitic volcanism through high-pressure equilibrium experiments and geochemical modeling. In Chapter 2, I define the crystallization sequence and petrogenesis of the young mare basalts collected by the Chang'e 5 mission and propose a model for melt generation in the Moon at ~ 2Ma. In Chapter 3, I estimate a minimum radius of ~1600 km for the Angrite Parent Body using near-liquidus equilibrium experiments. The implications for planet formation models of a differentiated moon-sized planetesimal accreting in the first 3 Ma of the Solar System are also discussed. In the fourth Chapter, I introduce a new experimental technique for studying melt migration in volcanoes, which allowed me to observe and describe the mechanisms that control melt migration in the upper crust. Together, these studies advance our knowledge of melt production and crystallization conditions in planetary interiors and provide fundamental insights into the geologic history of the Earth and other rocky bodies in the Solar System.