Petrological and rheological controls on volcanism to terrestrial planets

Abstract

Through experimental petrology and geodynamic modeling, processes of melting under thick lithospheres on the Earth and the moon are investigated. Phase equilibrium experiments were carried out on Apollo 14B and 15C picritic glasses (Chapters 5 and 6) and on a Sierran high-potassium lava (Chapter 1). These, along with petrologic modeling of Cascades high alumina olivine tholeiites (Chapter 4), yield information on depths and pressures of melt generation and constraints on source composition. Geodynamic modeling of lithospheric thinning processes, including delamination under the Siberian flood basalts (Chapter 2), gravitational instabilities in the lunar magma ocean cumulates (Chapter 7), and thinning and convection due to giant meteorite impacts (Chapters 3 and 8), has lead to new models for melt production. These studies together show how lithospheric thinning and unusual mantle compositions can lead to melting without calling on unusual mantle potential temperatures, and can explain the volumes and durations of continental flood basalts and lunar mare basalts.