High Pressure Geology and Volcanology 1

Enlarged view: High pressure apparatus built into the centrifuge — Image: L. Martin

The high pressure apparatus built into the centrifuge generates pressures equivalent to depth and temperatures encompassing the formation conditions of most magmatic rocks. The centrifugal acceleration enables the determination of melt viscosities or of crystal settling processes in magma chambers.

Enlarged view: Start of the experiment, are evenly distributed in the melt — Image: M. Schmidt

This experiment can be used to find out how long it takes until for example a chromite deposit has formed.
At the start of the experiment, the crystals (dark grey) are evenly distributed in the melt (light grey).

Then in the centrifuge the sample is exposed to 1500 times gravity and conditions similar to those in a magma chamber (10'000 bar pressure, 1300°C).

Enlarged view: At the end of the experiment, the crystals have settle at the bottom — Image: M. Schmidt

At the end of the experiment, the crystals have settle at the bottom of the sample and consolidated. From these experiments, we can calculate that in a 100 m thick magma body the settling of 1 cm sized crystals to the bottom of the chamber takes approximately 3 years.

Our group studies the physical and chemical conditions of magmatic processes in the Earth's interior, in the Moon and in the inner planets by using experiments.

What happens in a magma chamber before a volcano erupts? How does the core-mantle boundary look like?