The Earth showed its insides: the deep mantle of our planet was created in the laboratory

Scientists have created in the laboratory the deep mantle of the Earth

The scientists were able to recreate the state of the deep mantle of our planet in laboratory conditions. The research will help to study real rocks at high pressure and high temperature at a depth of about a thousand kilometers. The first results of the study startled the scientists. To conduct the study, they first deformed a real rock, compressing and heating olivine about 700 degrees to 400 thousand times the atmospheric pressure.

Under such extreme conditions, using the DESY PETRA III X-ray source, a mixture of the two most abundant minerals on the Earth, bridgmanite and ferropericlase, was created. It is believed that they are characteristic of the lower mantle of the Earth.

The researchers called the behavior of the mixture in the lower mantle unexpected, possible only during the passage of earthquake waves. Convection in the planet's mantle controls the tectonics of the Earth's strata. It is directly related to volcanic activity and earthquakes. But the deepest drill cores do not allow a glimpse into the planet's convection. Science believes that seismic behavior in deep strata is associated with crystals of mantle minerals.

They are the ones that cause even mantle flows. The texture of these minerals promotes irreversible movement within the crystal lattice that leads to plastic deformation. The most common of them are bridgmanite, magnesium silicate, and ferropericlase, magnesium and iron oxide.

The first is recognized as the most abundant mineral on the Earth, its presence in the soil is almost 40%. Understanding deformational behavior is important to anticipate mantle dynamics. Geological experiments investigating the lower layers were carried out on samples with one mineral. The new study aimed to investigate potential differences in the behavior of bridgmanite under the influence of multimineral influences.

By compressing olivine, a mineral in the upper mantle, and then heating it and compressing it again to a deeper, lower mantle pressure, the scientists observed its complex crystalline structure. The mechanisms of its deformation changed with temperature.

The results of the study are that ferropericlase is likely to undergo significant deformation, but the mineral does not contribute to the observed seismic anisotropy in the lower mantle.

Reference: “Does Heterogeneous Strain Act as a Control on Seismic Anisotropy in Earth’s Lower Mantle?” by Samantha Couper, Sergio Speziale, Hauke Marquardt, Hanns-Peter Liermann and Lowell Miyagi, 14 October 2020, Frontiers in Earth Science. DOI: 10.3389/feart.2020.540449