[1] The mantle plume hypothesis provides explanations for several major observations of surface volcanism. The dynamics of plumes with purely thermal origin has been well established, but our understanding of the role of compositional variations in the Earth’s mantle on plume formation is still incomplete. In this study we explore the structures of plumes originating from a thermochemical bound...

We have developed a finite element model of convection in a spherical, axisymmetric shell that we use to simulate upwelling thermal plumes in the mantle. The finite element method provides the flexibility to include realistic properties such as temperature-dependent viscosity, the focus of this paper. We used this model to investigate the effect of temperature-dependent viscosity on the structu...

...............................................................................................................................iv Chapter 1: Introduction ................................................................................................1 Chapter 2: Adjoint Method in Mantle Convection .............................................5 2.1 Theoretical Basis of the Adjoint Method ..........

Magnesiowüstite [(Mg,Fe)O] is the second most abundant mineral of Earth's lower mantle. Understanding its stability under lower mantle conditions is crucial for interpreting the physical and chemical properties of the whole Earth. Previous studies in an externally heated diamond anvil cell suggested that magnesiowüstites decompose into two components, Fe-rich and Mg-rich magnesiowüstites at 86 ...

Thermal conductivity of the Earth's lower mantle greatly impacts the mantle convection style and affects the heat conduction from the core to the mantle. Direct laboratory measurement of thermal conductivity of mantle minerals remains a technical challenge at the pressure-temperature (P-T) conditions relevant to the lower mantle, and previously estimated values are extrapolated from low P-T dat...