Images sent to Earth by the Perseverance rover from Mars confirm that there was once a lake on the planet.
Science Newsroom, Oct 7 (EFE) .- About 3.7 billion years ago, the cráter Lake from Mars it was a quiet lago fed by a small river that, after a sudden change in the climate, began to suffer sudden and energetic floods that washed large rocks from tens of kilometers upstream to the lake bed, where they still remain.
Until now it was an assumption of scientists but now, the first analysis of the images captured by the rover of the NASA Perseverance has confirmed it: Jezero Crater, which today is a dry, wind-eroded depression, was once a calm Martian lake.
The crater, which was chosen as the rover’s landing site after satellite images showed that this place was similar to river deltas on Earth, has just been studied and the conclusions were published in the journal Science.
The study has been led by scientists from NASA and the French CNRS, and has had the participation of the researcher from the Institute of Geosciences (IGEO) Jesús Martinez-Frias.
Amazing pictures of sediment layers on #Mars in this study. ????
Perseverance rover reveals an ancient delta-lake system and flood deposits at Jezero crater, Mars https://t.co/9tHXMOItvp
– Jérôme Juilleret (@Subsolum) October 8, 2021
“These geological studies of rocks and outcrops on Mars carried out by Perseverance confirm their importance in determining ancient Martian environments (paleoenvironments) and in establishing their relationships with water and habitability conditions,” explains Martínez-Frías in statements to EFE.
For Benjamin Weiss, a researcher at MIT and co-author of the study, when you look at the images, “you are basically seeing this epic desert landscape. The most desolate place you can visit. There is not a drop of water anywhere, and yet there is evidence of a very different past. Something very profound happened in the history of the planet ”.
The rover landed on the floor of the Jezero crater last February, just under two kilometers from the western part, but while NASA engineers remotely checked the operation of the rover’s instruments, two of its cameras, the Mastcam- Z and the SuperCam Remote Micro-Imager (RMI) captured high-resolution images of the crater and a small mound known as the Kodiak butte.
When the rover sent them to Earth, NASA’s Perseverance science team processed and combined them, and were able to observe different sediment beds.
The researchers measured the thickness, slope and lateral extent of each layer, and found that the sediments had not been deposited by the wind, but by the flow of water in a lake, by floods or other geological processes.
“Without getting anywhere, the rover was able to solve one of the great unknowns, which was that this crater was once a lake. Until we actually landed there and confirmed that it was a lake, it was always anyone’s guess, “acknowledges Weiss.
When the researchers looked at the images of the main outcrop, they saw large rocks and boulders embedded in the younger and upper layers of the delta; some were up to a meter wide and weighed several tons.
The team concluded that these huge rocks must have come from outside the crater or several kilometers upstream and that they were washed up to the lake bed by a flash flood that flowed up to nine meters per second and moved up to 3,000 cubic meters. of water per second.
These huge rocks located in the upper layers of the delta are the most recent deposited material, while the boulders rest on layers of older and much finer sediment, an indicator that, for much of its existence, the ancient lake was fed by a gently flowing river.
Over time, the crater suffered sudden floods that deposited large rocks in the delta and, later, a climate change – which is not known why it originated – caused the lake to dry up. Over the next billions of years, the wind eroded the landscape and created the crater we see today.
As the rover explores the crater, scientists hope to discover more clues about the climatic and hydrological evolution of the red planet because, if Jezero was a lake environment, its sediments could contain traces of ancient aquatic life.
On his next mission, Perseverance will search for places to collect sediment and samples that he will send to Earth for scientists to search for Martian biosignatures.