Earth’s volatile budget and deep volatile cycling: Earth’s outer core is composed of liquid iron-nickel. The metallic liquid in the outer core plays a crucial role in generating a magnetic field, which in turn shields us from harmful cosmic radiations. Geophysical evidence indicates that the density of the outer core is ~10% lower compared to pure iron-nickel alloys, which suggests the presence of lighter elements in the core to account for the density deficit. However, the identity and proportion of the light elements remain largely unknown. Due to uncertainty in the exact amount of life essential volatiles (e.g., carbon, nitrogen, hydrogen etc.) in the core, bulk Earth abundance of these elements remains controversial. I use first-principles molecular dynamics simulations of metallic melts with pure iron (Fe) and Fe-X where X is the light elements such as carbon and nitrogen. My study on the density and sound wave velocity of iron, iron-carbon, and iron-nitrogen melts revelated that Earth’s core could be the largest reservoir of terrestrial carbon.
Understanding various Earth processes from magma properties: Knowledge about the physical properties of molten rock is important to understand the origin and stability of magma/lava, and the magmatic processes at different times in Earth’s history. For instance, the partial melts at shallow depths tend to be buoyant and mobile, eventually leading to volcanic eruptions and crustal formation. Due to high compressibility, silicate melts at greater depths may become denser than the surrounding rocks and could accumulate at the major boundaries inside the Earth, including at the top of the transition zone, the lower mantle, and the core-mantle boundary. Most of the crustal material in modern Earth is the product of partial melting in the magmatic zone. Using the simulation results, I have estimated the density, viscosity, and other key properties of silicate melt for the entire mantle P-T regime. My calculation predicted that the basaltic melt with or without volatile could become denser than the mantle at the top and bottom of the mantle transition zone thereby providing a plausible explanation for low-velocity regions. Similarly, my estimation of the low viscosity of the Magma Ocean revealed that the crystallization of the magma ocean is likely to be fractional and could complete within a few million years.