Dynamics of Mush Column Magmatism: Experiments Involving Transport of Particle-Laden Fluids

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Dynamics of Mush Column Magamtism: Experiments Involving Transport of Particle-Laden FluidsEAR-0207254PI: MarshThe nature and behavior of the plumbing system that carries magma to large volcanic centers can be looked upon as a magmatic mush column. Mush columns are envisioned as a vertically extensive stack of horizontal sheets (or sills) and chambers of magma interconnected by a plexus of pipe-like and/or dike-like conduits stretching downward for distances as great as 50 km. Because of their longevity and complexity, mush columns may play a central role in the evolution of magma and in the general geologic evolution of Earth-like planets. Mush column dynamics may be central to understanding the connections between magmatism and volcanism, between eruptive flux and magma composition, between chamber and conduit geometry and cumulate bed formation, between conduit clogging and volcanic tremor, and between magma transport and layered intrusions, among many other issues. This project will design and build a scale model of a mush column to study experimentally the dynamics of magma charged with crystals as it ascends through a series of interconnected magma chambers. Particle-laden fluid will be used to simulate magma carrying crystals, where the fluid and the sizes and densities of the particles are carefully chosen to achieve dynamic similarity with melt and crystals in a real system. The geometry of the plumbing of the scale model will be based on geophysical and geological studies of real volcanic systems. A primary goal of this project is to delineate in detail how the loss, gain, and deposition of crystals depends on local and large scale geometry of the system and on the magnitude and time history of flux of magma. A series of reconnaissance experiments using a simple scale model has shown the feasibility of this approach to study transport and emplacement of crystal-rich magma.