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.