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Materials scientists at the University of California San Diego have performed powerful laser shock experiments on a perovskite mineral to better understand the geophysical processes in Earth’s deep interior and the mechanisms behind earthquakes deep within the planet.
Perovskites are a class of materials used in light-based technologies such as solar cells, LEDs and lasers. They are also the most abundant minerals in Earth’s mantle. Two of the mantle’s most abundant mineral perovskites, bridgmanite and wollastonite, are difficult to study directly because they are unstable under standard laboratory conditions. To get around this, researchers use a chemically different but structurally similar mineral, calcium titanate, as an analogue.
In a new study, researchers used high power laser shock compression to recreate the extreme pressures and temperatures found deep inside the Earth. They discovered that calcium titanate deforms more like metals by forming dense networks of line and planar defects in contrast to completely disordered amorphization typically found in covalent materials like diamond — that may explain how mantle rocks respond to stress. These findings provide new insights into the processes that drive deep-focus earthquakes, which occur hundreds of kilometers beneath the Earth’s surface, and may also inform the effects of meteorite impacts on planets.
The study, published in Acta Materialia, was led by UC San Diego researchers Boya Li and Marc Meyers. This research was partially supported by the Department of Energy, National Nuclear Security Administration (award DE-NA0004147).