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地球化学专业学术报告

报告地点: 
环境资源楼824会议室
报告时间: 
2017-04-24 15:00
报告人: 
Prof. Oliver D. Tschauner
报告人简介: 
University of Nevada Las Vegas High Pressure Science and Engineering Center, Department of Geoscience
报告题目: 
Mineralogy of extreme conditions
报告内容简介: 

 

Defining mineralogy of extreme conditions as a subfield in geoscience is meaningful only with respect to specific scientific tasks that it shall address. In case of mineralogy of extreme conditions there are two principal tasks:  the deep Earth and large scale impacts on Earth or between meteorite-parent bodies. There

are plausible extensions such as to pseudotachylites from earthquakes, but I focus in my talk on these two principal topics.

 

After briefly introducing the method, I will review the progresses in the understanding of impacts based on the recent achievements in shock-metamorphic mineralogy. Emphasis is put on the discovery of bridgmanite as a case study how solving a particular, challenging problem can open new areas of research.

 

Shock-induced high pressure mineralogy probes an extensive compositional space, often beyond of what is experimentally achievable. I will show how this extensive set of compositions and structures allows us to define thermodynamic mixing relations and endmembers of important rock-forming or accessory minerals with application to deep Earth. This is the second topic of my talk:  I will show the mixing relations of ferrous-ferric bridgmanite and how it explains some of the properties of this mineral. Then I show that the current concept of solid solutions of majorite-bearing garnets is incorrect and outline the crystal chemistry of majoritic garnets.