Magmatism and volcanism on Io

Thesis

Global volcanism has implications for planetary evolution far beyond the surface features that we observe. Magmatic and volcanic processes control the structural, thermal and compositional evolutions of the bodies where they operates. Jupiter’s moon Io, the most volcanically active body in the Solar System, is an extreme ‘end-member’ that allows us to investigate the effects of planetary magmatism and volcanism in relative isolation of other processes. Previous research has generally investigated melting and magmatism within Io’s partially-molten mantle separately from the volcanic systems in its lithosphere. In this thesis I present a suite of models that move beyond previous works by coupling mantle melting and magmatism to lithospheric evolution and volcanism. With this approach I show that magmatic intrusions within Io’s lithosphere are a fundamental part of the global heat balance, delivering significant mass and energy to the lithosphere and controlling its thickness. As well as transporting heat, magmatism and volcanism also transport chemical species. With the inclusion of a simple chemical system, I show how magmatism and volcanism control Io’s compositional evolution, leading to a layered mantle structure and the generation of ultra-high-temperature magmas in the deep mantle that can explain Io’s highest temperature eruptions. Finally, the structural implications of magmatism and volcanism can be related to underlying tidal heating; I show how tidal heating distributions can be inferred from improved observations of long-wavelength lithospheric thicknesses and topography.

Authors: Spencer, D

• DOI: 10.5287/ora-koebpj5gg
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: Geophysics; Io; Volcano; Geodynamics; Volcanism; Two-phase flow; Fluid dynamics; Magmatism; Planetary
• Subjects: Geophysics; Volcanology; Planetary science; Fluid dynamics; Geodynamics