冰与橄榄石的晶格优选定向的实验研究进展：从实验室到极地与火星

綦超 特聘研究员

中国科学院 地质与地球物理所

2021.12.03（星期五）15:00，理科二号楼2821

报告摘要：

Crystallographic preferred orientations (CPOs) of minerals develop due to plastic deformation, and in return strongly affect the mechanical response to deformation. In this presentation, the speaker focuses on the recent studies of CPO in ice and olivine. (1) Water ice makes glaciers and ice sheets on Earth, polar ice caps on Mars, and the surface and subsurface layer on icy satellites and dwarf planets. A transition in the patterns of the crystallographic preferred orientation (CPO) was found in laboratory experiments performed under different conditions. Based on experimental observations, the speaker proposes that a transition in the dominant recrystallization process occurs with increasing stress, increasing strain, or lowering temperature, from grain boundary migration to lattice rotation, which causes the transition in the CPO patterns. (2) Olivine, the major mineral in the Earth’s upper mantle, also constitute a major part in the mantle of the Mars. Different from on the Earth, where olivine is mostly magnesium-rich, the Martian olivine is iron-rich. Based on deformation experiments on olivines with different iron content, the speaker found that the CPO development is similar for iron-rich and iron-poor olivine. Thus, the seismic anisotropy in the mantle of Mars, if caused by the CPO of olivine, can be interpreted based on our understanding of the mantle of Earth, even though the iron content in olivine is different on Mars than on Earth.

报告人简介：

2008年在北京大学获得学士学位，2014年在明尼苏达大学获得博士学位。先后在宾夕法尼亚大学和明尼苏达大学做博士后工作，2018年在中科院地质与地球物理所任副研究员。冰物理实验室负责人，中组部人才引进计划入选者。主要方向为实验岩石物理学和行星固体物理学。从事橄榄石和水冰的变形实验，研究地球与行星内部物质运动。主要关注水冰微结构与塑性变形之间的相互作用、地球与行星自然条件下水冰的流变学性质、半熔融岩石/冰的流变学性质和微结构演化等问题。曾在Nature，PNAS，EPSL，GRL，JGR等多个国际高水平期刊上发表论文十余篇。