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Scientists Discover Molten Layer Covering Martian Core

By Georgia Jiang

NASA’s InSight mission to Mars helped scientists map out the planet’s internal structure, including the size and composition of its core, and provided general hints about its tumultuous formation.

But findings from a paper published Wednesday in the journal Nature by an international research team that includes a University of Maryland scientist could lead to reanalysis of the findings. The team discovered the presence of a molten silicate layer overlying Mars’ metallic core—providing new insights into how Mars formed, evolved and became the barren planet it is today.

The paper details the use of seismic data to locate and identify a thin layer of molten silicates (rock-forming minerals that make up the crust and mantle of Mars and Earth) between the Martian mantle and core. This allowed the researchers to determine that Mars’ core is both denser and smaller than previous estimates, a conclusion that better aligns with other geophysical data and analysis of Martian meteorites.

Vedran Lekic, a UMD professor of geology and co-author of the paper, compared the molten layer to a “heating blanket” covering the Martian core.

“The blanket not only insulates the heat coming from the core and prevents the core from cooling, but also concentrates radioactive elements whose decay generates heat,” Lekic said. “And when that happens, the core is likely to be unable to produce the convective motions that would create a magnetic field—which can explain why Mars currently doesn’t have an active magnetic field around it.”

Without a functional protective magnetic field, a terrestrial planet such as Mars would be extremely vulnerable to harsh solar winds and lose all the water on its surface, making it incapable of sustaining life.

The team’s conclusions support theories that Mars was at one time a molten ocean of magma that later crystallized to produce a layer of silicate melt enriched in iron and radioactive elements that became the base of the Martian mantle. The heat emanating from the radioactive elements would then have dramatically altered the thermal evolution and cooling history of the red planet.

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