Leonard David's INSIDE OUTER SPACE

Lander and Zhurong Mars rover.
Credit: CNSA/Inside Outer Space screengrab

China’s Zhurong Mars rover has been radar-scanning the subsurface of the Red Planet.

Those scans reveal a multi-layered geological make-up below the ground of Mars, which was found to be far more complex than previously thought, according to Ling Chen, a researcher at the Institute of Geology and Geophysics under the Chinese Academy of Sciences. She is a co-author of new research just published in the journal, Nature.

The Zhurong rover of the Tianwen-1 Mars mission touched down on the southern Utopia Planitia – a vast plain on the northern hemisphere of Mars, in May last year and started to make ground-based detections.

Credit: CNSA

In-depth analyses

“The observation showed Mars has a layered subsurface. Such mission is the first of its kind. In the newest finding, radar detection disclosed the structure of layers up to [roughly 260-feet] 80 meters underground,” Ling told China Central Television (CCTV).

Chinese scientists have carried out in-depth analyses of the low-frequency radar data obtained by the rover within the first 113 Martian days it spent on Mars last year, during which it traveled a distance of 1,171 meters.

In doing so, researchers acquired high-resolution structural stratification images and stratum physical property information of Mars at a depth of 80 meters.

Ling Chen, a researcher at the Institute of Geology and Geophysics under the Chinese Academy of Sciences.
Credit: CCTV/Inside Outer Space screengrab

Meters thick

They found that there are two sedimentary strata with an upward-thinning pattern beneath the meters-thick Martian soil layer, indicating that there could have been water-driven Martian surface modifications made from between 3.2 to 3.5 billion years ago, according to CCTV.

But the low-frequency radar imaging results also showed that there was no water-rich layer down to the 80-meter depth range along the route that Zhurong rover had traveled during the study period.

“Mars is actually quite complex and each part is undergoing different changes at the time, which provides a new direction for our future research. That is to say, we have to consider the spatial and temporal variations of Mars in order to obtain a better understanding of the planet’s evolution and structure,” Ling said.

China’s Mars rover. Credit: Zou Yongliao, et al.

Layer upon layer

As detailed in the research paper, the first layer, no thicker than 33-feet (10 meters), is interpreted as the Martian regolith.

The second layer, from 10 to 30 meters in depth, contains rocky blocks. These presumably have taken shape in roughly the past 1.6 billion years, and their clast sizes increase with depth. A clast is a fragment of rock or mineral.

China’s Zhurong rover.
Credit: CNSA

The third layer, in the 30 to 80 meters depth range, is composed of larger rocky blocks, representing an older, probably more substantial geological event happening as early as 3.5 to 3.2 billion years ago, according to the study.

To access the research paper – “Layered subsurface in Utopia Basin of Mars revealed by Zhurong rover radar” – go to:

https://www.nature.com/articles/s41586-022-05147-5