Saswata Hier-Majumder

Assistant Professor

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Contiguity.

Magma nanotube.

News
Congratulations Dr. Drombosky
April, 2014
Tyler Drombosky successfully defended his thesis on April 4th, 2014. In his doctoral dissertation, Tyler developed a novel technique for modeling microstructure in deforming, partially molten rocks at the base of the Earth's tectonic plates. Tyler will move on to work at Luminal.


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Subsurface ocean in Triton.

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Simulated microstructure in an isotropic partially molten rock. (Left) a single grain, (right) a unit cell as the melt volume fraction increases from 0.05 to 0.26, the disaggregation fraction.

Microgeodynamics

Microgeodynamics is a theoretical framework that describes the dynamic, transient microstructure in partially molten rocks. Melt resides in tiny tubules, pockets, and films along the edges and corners of mineral grains of partially molten rocks. In dynamic environments, like the Earth's interior, forces of convection stretch, squeeze, or realign these microscopic units, changing the geometry. The resulting microstructure influence the seismic and electromagnetic signature, control the efficiency of melt transport, and modify the chemical composition of the partially molten rocks.

Derived from two lines of models developed by petrologists, ceramicists, and materials scientists, microgeodynamics is based on a set of coupled continuum mechanical conservation laws over multiple, interacting domains. We are developing computational techniques suitable for a large number of applications of microgeodynamics. Two outcomes are a SemiAnalytical Model (SAM) and a Boundary Elements Model (BEM).

The results of this formulations have been used to detect the seismic signature of the ultralow velocity zones in the core-mantle boundary. Using this code, undergraduate Matt Abbott recently demonstrated that small amounts of wetting melts, characterized by low dihedral angle, can mimic the seismic signature of larger amounts of nonwetting melts. Thus, potentially allowing a mechanism to infer the chemical nature of melts from their seismic signatures.

This research is supported by the National Science Foundation.