제목: Fundamental Understanding of Physicochemical Properties of Minerals in Geological Processes Using Various Quantitative Tools​​​​​​​​​​​​​​​​​

장소: 과학관 B102호 

Abstract:

 Understanding the structural, physical, and chemical properties of minerals occurring in geological systems is often complicated due to multiple components, phases, and variables involved in the systems. Recently, fundamental investigations on these subjects have been made possible by the refinement and widespread use of spectroscopic and microscopic techniques as well as fast development in computational methods. In this presentation, I demonstrate the application of quantum-mechanical modeling approaches for understanding thermodynamic properties of solid solution in minerals as well as the use of synchrotron X-ray approaches to elucidate structural and morphological relationships between multiple phases upon mineral replacement reactions.  

 In various geological systems, minerals rarely occur as a pure end member but form solid solution to a certain degree or contain trace amounts of foreign ions in their structures. There have been numerous field and experimental studies investigating ionic substitution in minerals, while quantifying their thermodynamics and mechanisms are often difficult to empirically obtain. My research explores ionic substitution in the mineral structure in atomistic scales mainly based on density functional theory (DFT) calculation. Combined with statistical thermodynamic analysis, DFT modeling can be very useful to investigate complex solid solution systems (e.g., involving multiple atomic sites) allowing for predicting energetic stabilities of minerals in hydrothermal and magmatic systems.

 The mineral replacement is a coupled dissolution-growth process in which a primary mineral dissolves in contact with fluid and is replaced by a more stable secondary mineral. Understanding mineral replacement reactions is essential in many natural and industrial processes including metasomatism, diagenesis, and metamorphism, and nuclear waste disposal. My research pursues mechanistic understanding of mineral replacements based on synchrotron nanoscale X-ray imaging.  Combined experimental and analytical approaches have been developed to understand how mineral replacement is modified by the crystallography of the primary and secondary mineral.