Scientists used images from the rover’s cameras
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 Perseverance’s landing in February – suggest that the region experienced significant late flood events.
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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 that the fan-shaped delta protruded, 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 east face, showing what a geologist would expect to find in a river delta on Earth.
“We interpret the presence of sloping levels in these outflows as evidence of deltas that have moved into a lake. In contrast, fan levels at the top are composed of boulder conglomerates, formed by episodic high-energy flooding. make a statement.” 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,” said Nicolas Mangold, a persistence scientist at the Laboratoire de Planetologie et Geodynamics in Nantes, France, and lead author of the paper, 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 pays down big dividends. The road is being done.”
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.
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NASA said the images provided the team with insight into where they might best look to collect and cache rock and sediment samples.
Mastcam-Z and RMI found stones and boulders further afield, 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 best-grained material at the bottom of the delta. And the boulders at the top will enable us to sample older fragments of crustal rocks. The core of both sampling and caching. Objectives are rocks before Mars sample return.”
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.
“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 Mars is almost dry 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,” said team member Tanja Bosak, associate professor of geophysics 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 a lot of potential.”