Mars's crust more complex, evolved than previously thought
Researchers led by Valerie Payré, assistant professor in earth and environmental sciences at the University of Iowa, have found the early crust on Mars is more complex in origin than previously thought. The researchers located nine locations in Mars's southern hemisphere (see image, above) that were rich in a mineral called feldspar. Feldspar is associated with a terrain that has more than a simply volcanic origin. The finding may mean Mars's formation may be similar to Earth's planetary beginnings." Credit: Valerie Payré, University of Iowa

The early crust on Mars may be more complex than previously thought.

The basaltic surface of Mars is the result of billions of years of volcanism and lava flows. Because Mars did not undergo full-scale surface remodeling like the shifting of continents on Earth, scientists thought it was a simple story.

In a new study, researchers found areas in the Red Planet's southern hemisphere with higher concentrations of a chemical element than what would be expected in a basaltic setting. Material that was embedded miles below the surface was exposed by space rocks that slammed into Mars. The study was published in the journal in November.

According to the study's author, there is more silica in the composition that makes the rocks not basalt. The crust on Mars is more complex than we've been told. It's more about understanding how Earth's crust formed.

About 4.5 billion years ago, Mars formed, according to scientists. There are many theories as to how the Red Planet came into being. One idea is that Mars was formed from a titanic collision of rocks in space that created a magma ocean. The theory says that the ocean gradually cooled and that it would be basaltic.

There is a theory that parts of the first crust on Mars were different from basaltic and that the magma ocean was not all-inclusive.

Previous research had indicated that the southern hemisphere was the oldest part of the planet. The researchers found that many of the locations were rich in feldspar, a mineral associated with lava flows that is more silicic than basaltic.

The first clue was this. The terrains are rich in feldspar.

The chemical composition in the areas where Feldspar was found was more basaltic. That didn't deter the researchers from using THEMIS, an instrument that can detect the presence of a substance on the surface of Mars. The terrain at their chosen locations was found to be more silicic than basaltic.

In addition, meteorites such as Erg Chech 002, discovered in the Sahara and dating roughly to the birth of the solar system, show the same mineral compositions that the team observed on Mars.

It was dated to 4.2 billion years old, making it the oldest crust found on Mars.

Payré was surprised by the find.

She says that there have been rovers that have seen rocks that were more silicic than basaltic. There was an idea that the crust could be more porous. We don't know how the early crust was formed or how old it is, so it's a mystery.

Our planet's original crust has been wiped out due to the shifting of continental plates for billions of years. Insights into Earth's origins may be offered by the finding.

Payré says that we don't know when life first appeared. Many people think the two are related. Understanding what the crust was like a long time ago can help us understand our planet's evolution.

At Northern Arizona University, Payré worked as a researcher. She became a member of theUI in August. Two authors from Northern Arizona are contributing.

V. Payré et al, An Evolved Early Crust exposed on Mars, was published in a research letter. It was published on 10.1029/2022GL099639.

Journal information: Geophysical Research Letters