Application of high pressure and high temperature experiments to Earth science
报告内容简介:High pressure and high temperature experimental studies have been widely used to address many different geoscience problems, such as physical or chemical properties of earth materials, partitioning of elements during melting or crystallization, behavior of minerals or rock samples under different stressing conditions et al. My research interests include two different parts: (1) the effect of compositional change on the physical properties of solid solutions. I took garnet binary pyrope-grossular (Mg3Al2Si3O12-Ca3Al2Si3O12) as an example, which provides an excellent solid-solution system for the study of non-ideal mixing behavior, because of the large size difference between divalent Mg2+ and Ca2+ (0.89 vs 1.12 in 8 coordination) (Shannon 1976). To clarify the disagreements among the literature studies and to further constrain the mixing properties of pyrope-grossular garnet solutions, I have performed experimental studies on synthesized garnet solid solution by using multi-anvil device, comprehensive X-ray diffraction powered with synchrotron light sources. Our new results show that the nonlinear compositional dependence of thermo-compression may be related to the elastic structural strain caused by substitution of Mg and Ca. And the exsolution of pyrope-grossular garnet at high pressure is confirmed by laboratory observation for the first time. (2) the formation or early differentiation of planets. I will talk about our new melting experimental results on an enstatite chondrite, showing how we use high pressure and high temperature experiments to model the differentiation process of a planet.