Our recent research in news
ASU researchers discover new mineralogy of the deep Earth. ASU News, Phys.org
Earth's Core May Be Causing Strange 'Anomalies', Study Suggests. ASU New, Vice
Diamonds and rust at the Earth's core-mantle boundary. ASU News, Newsweek
Carbon-rich planets made of diamonds may exist beyond our solar system, study says. CNN
Uranus and Neptune: Stardust in the deep interior of low-mass planets. Nature Astronomy News and Views
Exogeology: The labs that forge distant planets here on Earth. Nature News Feature
Through high pressure experiments, we investigate rocks from exoplanets, as their compositions can vary significantly from those of Earth. These compositional differences have the potential to affect the evolution and dynamics of rocky, Earth-like exoplanets. Recent examples: diamond-rich planets (Horn et al., 2020, Planetary Science Journal), silicon-carbide planets (Nisr et al., 2016, JGR-Planets).
Sub-Neptunes are commonly found in our galaxy, and they can either have a rocky interior with a dense hydrogen-rich atmosphere or a thick layer of water. The relationship between these two types of sub-Neptunes remains unclear. To investigate, we study the chemical reactions between silicate/oxide minerals and hydrogen, which could release oxygen from silicates and create water. Recent examples: formation of water from reaction between oxide melt and dense hydrogen (Horn et al., 2023, Planetary Science Journal).
Uranus, Neptune, and waterworld exoplanets
Uranus and Neptune are the two water-rich planets in our solar system, and some sub-Neptune exoplanets are also believed to be water worlds. On these planets, water exists under extreme conditions of high pressure and high temperature, interacting with minerals and rocks. To gain insights into the internal structure and geochemical cycle of these water world planets through high pressure experiments. Recent examples: water-silica mixing (Nisr et al., 2020, PNAS; Kim et al., 2021, Nature Astronomy).
Earth's lower mantle
Fascinating structures have been unveiled within the Earth's interior through seismic imaging investigations. Dynamic simulations have demonstrated that the formation and destruction of these structures can have a significant impact on surface tectonics and volcanic activities. Our research offers crucial physical and chemical parameters that aid in comprehending the origins of these structures. At ASU, we collaborate with a diverse group of experts, including Ed Garnero (seismology), Mingming Li (geodynamics), and Joe O'Rourke (dynamics), spanning geophysics, geology, and planetary science to foster a holistic understanding of the Earth's interior. Recent examples: deep water transport (Chen et al., 2020, EPSL), deep melting (Kim et al., 2020, GRL), nanocrystalline metal iron in shocked meteorite (Bindi et al., 2020, Science Advances), new mineralogy of the deep Earth (Ko et al., 2022, Nature).
Earth's core-mantle boundary
Water is likely transported to the core-mantle boundary. Water can facilitate the chemical reaction between mineral phases of the lower mantle and the liquid iron of the outer core at the core-mantle boundary. Our research investigates the chemical reactions that occur between hydrous minerals and liquid iron alloys under high-pressure and high-temperature conditions relevant to the Earth's core-mantle boundary. This research aims to provide insight into the origin of the fine-scale structures observed in the region, including ultra-low velocity zones (ULVZs), core-rigidity zones (CRZs), and the E' layer located in the outer core. Recent examples: diamond at the core-mantle boundary (Ko et al., 2022).
Although hydrogen is the most abundant element in our solar system, the storage of hydrogen within the Earth's deep interior is not well understood. Our research focuses on investigating how the presence of hydrogen affects the chemistry, structure, and dynamics of the Earth's core. Recent examples: discovery of a new Fe-Si-H alloy (Fu et al., 2022, PRB), hydrogen solubility in FeSi alloys (Fu et al., 2022, Am Min), snow in the Earth's outermost core (Fu et al., 2023, Nature).
Earth's early hydrogen
To understand the early geological history and the storage of volatiles, it is crucial to examine the interplay between the atmosphere and magma ocean. With the aid of a hydrogen loading system and micro-second pulse laser heating technique, we can now attain temperatures high enough to investigate the chemical reactions that occur between hydrogen and silicate melts, as well as between hydrogen and iron liquids, under the pressure-temperature conditions of the deep magma ocean. Recent examples: super-stoichiometric Fe-H liquid (Piet et al., 2023, GRL).
Mars deep hydrogen and water
The Mars dynamo stopped abruptly, which may have played a role in its transition from a wet environment to the current dry environment on its surface. The reason for the sudden halt in dynamo from the Martian core is unknown. Our research focuses on investigating the interaction between the core and mantle of Mars, facilitated by water and hydrogen, to shed light on this. Recent examples: water and dynamo in deep Mars (O'Rourke and Shim, 2019, JGR-Planet), hydrogen in the Martian core (Piet et al., 2021, JGR-Planet).