Space & Cosmos

X-rays advance understanding of Earth’s core-mantle boundary and super-Earth magma oceans

Schematic diagram of the experimental setup available at the MEC end station. Four epiX 10k detectors cover the Q range from 15 to 106 nm-1 with an X-ray beam energy of 17 keV. The complete signal can be reconstructed by stitching together the diffuse scattering recorded by each detector. Credit: Nature Communications (2024). DOI: 10.1038/s41467-024-51796-7

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory have revealed new details about Earth’s core-mantle boundary and similar regions found on exoplanets.

A research team led by scientist Guillaume Morard from the Universities of Grenoble and Sorbonne in France used SLAC’s Linac Coherent Light Source (LCLS) X-ray laser to investigate the behavior of lava under extreme conditions. The results were published in the journal Nature Communications.

“This study represents a major advance in our understanding of the deep Earth,” said co-investigator Arianna Gleason, a senior scientist at SLAC. “This discovery highlights the potential of advanced X-ray technology to reveal hidden secrets of Earth and beyond.”

About 1,800 miles below Earth’s surface lies a swirling region of magma sandwiched between a solid silicate-based mantle and a molten iron-rich core, the core-mantle boundary. This is a remnant from an older era, about 4.3 to 4.5 billion years ago, when the entire Earth melted. The region’s extreme pressures and temperatures make it difficult to study, but it contains clues about Earth’s origin story and insights into the planet’s internal processes.

To overcome this challenge, researchers used advanced X-ray techniques to recreate the conditions expected in the middle to lower mantle of an exoplanet two to three times the size of Earth. By using hard X-rays at higher energy levels than previously possible, researchers were able to see how atoms in molten rock are arranged. The research team also used computer simulations to compare with experimental data, providing a comprehensive view of the properties of the molten silicate.

One surprising result concerned the role of iron in lava. Contrary to expectations, changing the iron content did not significantly change the density of the rocks. This discovery is particularly relevant to our understanding of Earth’s formation. The Earth’s surface was once lava, and the difference in density between crystalline and molten materials had a major influence on the planet’s development.

The study also suggests that this atomic response to compression may change the properties of melts at pressures expected to be found in the magma oceans of super-Earths, exoplanets with about three times the mass of Earth. It suggests that there is. This could affect their early development in a way that is different from smaller rocky planets like Earth and Venus in our solar system.

This study highlights the importance of advanced experimental tools for studying high-pressure and high-temperature conditions. The research team hopes that their findings will lead to further development of these tools and open new research avenues in Earth and planetary science.

“Now that we have data of this quality and know that these conditions can be achieved, we want to push the exoplanet regime even further,” Gleason said. “The ability to generate pressures equivalent to three times the Earth’s mantle conditions is exciting. This expands our understanding of the properties of silicates under extreme conditions. important for both.”

Further information: Guillaume Morard et al., Structural evolution of liquid silicates under conditions inside super-Earths, Nature Communications (2024). DOI: 10.1038/s41467-024-51796-7

Provided by SLAC National Accelerator Laboratory

Citation: X-rays advance understanding of Earth’s core-mantle boundary and super-Earth magma oceans (October 3, 2024) https://phys.org/news/2024-10-rays-advance-earth – Retrieved October 3, 2024 from coremantle.html

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