Mars' Crust is more Complicated and Developed than Previously Thought: Research

According to a new study, the primordial crust of Mars is more complicated and evolved than previously imagined. Researchers discovered that the Martian crust contains higher amounts of the chemical element silicon, implying that Mars' original surface was similar to Earth's first crust.

The surface of Mars is uniformly basaltic, the result of billions of years of volcanism and flowing lava that finally cooled. Because Mars' crustal history was assumed to be relatively simple because it did not undergo full-scale surface remodelling like the shifting of continents on Earth.

A new study, however, discovered places in Mars' southern hemisphere with higher quantities of silicon, a chemical element, than would be predicted in a solely basaltic context. The silica concentration has been exposed by space debris colliding with Mars, extracting material imbedded miles beneath the surface and unveiling a hidden past.

"There is more silica in the composition, which makes the rocks not basalt, but what we call more developed in composition," explains Valerie Payre, the study's corresponding author and assistant professor in the Department of Earth and Environmental Sciences at the University of Iowa. "This demonstrates that the formation of the crust on Mars is far more intricate than we previously thought."

So it's more about comprehending that process, particularly what it entails for the formation of the Earth's crust."

Mars, according to scientists, created roughly 4.5 billion years ago. The exact origin of the Red Planet is unknown, but there are theories. One theory holds that Mars developed as a result of a massive collision of rocks in space, which resulted in a fully liquefied condition, commonly known as a magma ocean. According to the notion, the magma ocean gradually cooled, resulting in a crust, similar to a layer of skin, that is uniquely basaltic.

Another view is that the magma ocean was not all-encompassing, and that areas of Mars' initial crust had a distinct origin, with silica concentrations differing from basaltic.

Payre and her colleagues examined data from the Mars Reconnaissance Orbiter for the planet's southern hemisphere, which earlier study indicated was the oldest. The researchers discovered nine feldspar-rich areas, such as craters and cracks in the topography, which are associated with silicic lava flows rather than basaltic lava flows.

"This was the first hint," Payre explains. "We investigated the silica concentrations there because the terrains are feldspar-rich."

Feldspar had previously been discovered in other parts of Mars, but subsequent investigation revealed that the chemical makeup in those locations was more basaltic. That did not stop the researchers, who used another device called THEMIS to detect silica concentrations via infrared wavelength reflections from the Martian surface. Using THEMIS data, the researchers discovered that the landscape at their chosen areas was more silicic than basaltic.

Meteorites like Erg Chech 002, discovered in the Sahara and dating roughly to the creation of the solar system, have comparable silicic and other mineral compositions as the scientists observed in the nine places on Mars.

The crust was also dated to around 4.2 billion years, making it the oldest crust discovered on Mars to date.

Payre admits she was astonished by the discovery.

"There have been surface rovers that have observed rocks that were more silicic than basaltic," she explains. "There was speculation that the crust could be more silicic. But we never knew, and still don't know, how the early crust developed or how old it is, so it's still a mystery."

While Mars' crustal genesis is unknown, Earth's crustal history is much more obscure, as any remnants of our planet's initial crust have been long destroyed owing to billions of years of continental plate shifting.

Nonetheless, the discovery could shed light on Earth's beginnings.

"We don't know the origins of our planet's crust; we don't even know when life first appeared," Payre explains. "Many people believe the two are related." Understanding what the crust was like a long time ago could help us grasp our planet's entire evolution."

Payre worked as a postdoctoral researcher at Northern Arizona University. She started at the UI in August.

The study, titled "An evolved early crust exposed on Mars revealed using spectroscopy," was published online Nov. 4 in Geophysical Research Letters.

(source : ANI)