Back to top


Prof. Oliver D. Tschauner
University of Nevada Las Vegas High Pressure Science and Engineering Center, Department of Geoscience
Mineralogy of extreme conditions


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.