Mars Lake’s existence confirmed, NASA’s persistence team confirms floods

NASA’s Perseverance Mars rover team has confirmed that the Red Planet’s Jezero crater was once the site of the Delta-Lake system.

In a study published Thursday in the journal Science, researchers also write that images from the rover — taken three months after Persistence’s landing in February — suggest that the region experienced significant late flood events.

The images were taken from long and steep slopes in the delta called escarpments, or “scarps”, which were reportedly formed from sediment at the mouth of an ancient river that fed the lake.

The photos showed the fan-shaped delta’s face bulging out, the team said was invisible from orbit and records the crater’s hydrological evolution.

The rock outcrop “Kodiak” was only imaged from orbit, but the images revealed its stratigraphy along the eastern face, showing what a geologist would expect to find in a river delta on Earth.

This image of a slope, or scarp - a long, steep slope - along the delta of Mars' Jezero crater was generated using data from the Perseverance rover's Mastcam-Z instrument.
This image of a slope, or scarp – a long, steep slope – along the delta of Mars’ Jezero crater was generated using data from the Perseverance rover’s Mastcam-Z instrument.
NASA/JPL-Caltech/LANL/CNES/CNRS/

“We interpret the presence of sloping levels in these outflows as evidence of deltas that have advanced into a lake. In contrast, the uppermost fans are made of boulder conglomerates, deposition by episodic high-energy floods. do,” the study authors wrote. “This sedimentary succession indicates a transition from a continuous hydrological activity to a highly energetic short-duration river flow in a near-lake environment.”

“Such well-preserved stratigraphy has never been seen before on Mars,” Nicolas Mangold, a Persistence scientist at the Laboratoire de Planetologie et Geodynamics in Nantes, France, and the paper’s lead author, said in a NASA release. “It is this important observation that enables us to confirm once and for all the presence of a lake and river delta in Jezero. Gaining a better understanding of the hydrology months before our arrival in the delta will pay off big dividends down the road. gonna pay.”

The photos that led them to these conclusions were taken by Perseverance’s left and right Mastcam-Z cameras in addition to its remote micro-imager.

NASA said the images provided the team with insight into where they might best look to collect and cache rock and sediment samples.

The science team in this image captured by the Perseverance rover's Mastcam-Z instrument on April 17, 2021
The science team looks at the escarpment referred to as “Scarp A” in this image captured by the Perseverance rover’s Mastcam-Z instrument on April 17, 2021.
NASA/JPL-Caltech/ASU/MSSS

Mastcam-Z and RMI found stones and boulders on the front, which the team said may have been carried by high-speed oncoming flash flooding.

“These results also have a bearing on the strategy of selecting rocks for sampling,” said Sanjeev Gupta, a Perseverance scientist at Imperial College, London, and a co-author of the paper, in a statement. “Our best bet is probably to find evidence of organics and biosignatures in the fine grained material at the bottom of the delta. And the boulders at the top will enable us to sample older fragments of crustal rocks before Mars sample return. Both for sampling and caching are the main purposes.”

Finally, scientists described the water level of Lake Ezero as fluctuating tens of yards before its disappearance – although it is not known whether the change was the result of floods or more gradual, environmental changes.

The team determined that the changes occurred later in the delta’s history and that the lake level was at least 330 feet below the highest level.

This image of “Kodiak”—a remnant of a fan-shaped deposit of sediment known as a delta—was taken by Perseverance’s Mastcam-Z instrument on February 22, 2021, inside Mars’ Jezero Crater.
NASA/JPL-Caltech/ASU/MSSS

“A better understanding of Jezero’s delta is the key to understanding changes in hydrology for the region,” Gupta said, “and could potentially provide valuable insight into why the entire planet dried up.”

NASA believes that Mars dried up about 3.5 billion years ago and that the lake existed about 3.7 billion years ago.

Delta will be the site for the rover team’s second science mission in 2022.

“We now have the opportunity to look for fossils,” team member Tanja Bosak, associate professor of geobiology at MIT, told MIT News. “It will take some time to get to the rocks that we expect to actually sample for signs of life. So, this is a marathon, with great potential.”

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