NASA’s Perseverance Mars rover successfully collected its first pair of rock samples from a Martian boulder dubbed "Rochette", and scientists are already gaining new insights into the geological history of the landing site inside Jezero Crater. After collecting its first sample, nicknamed “Montdenier” on September 6, the team collected a second, “Montagnac,” from the same rock on September 8.
Chemical analysis of the samples shows that Rochette is basaltic in composition and may be the product of lava flows. The volcanic origin of the rock could help scientists accurately date when it formed, providing glimpses into an ancient past when Mars was still volcanologically active and better pinpointing the age of Jezero Crater, formed more than 3.5 billion years ago.
What’s more, salt minerals have been spotted within these rocks. These salts may have formed when groundwater flowed through and altered the original minerals in the rock, or more likely when liquid water evaporated, leaving the salts. The salt minerals in these first two rock cores may also have trapped tiny bubbles of ancient Martian water. If present, they could serve as microscopic time capsules, offering clues about the ancient climate and habitability of Mars. Salt is also well-known on Earth for its ability to preserve signs of ancient life.
“It looks like our first rocks reveal a potentially habitable sustained environment,” said Ken Farley of Caltech, project scientist for the mission, which is led by NASA’s Jet Propulsion Laboratory in Southern California. “It’s a big deal that the water was there a long time.”
The landing site was chosen as the presence of a large canyon and a fan-shaped river delta suggest that the crater once hosted a lake. This hypothesis is further supported by the sediments found inside the crater. Thanks to NASA's Mars Reconnaissance Orbiter, the chemical composition of the ground can be mapped from orbit. Based on the analyzed spectral data, Jezero Crater contains high concentrations of calcium, aluminum, and magnesium, indicating the presence of sediments with clays and carbonates. On Earth, such minerals form by chemical alteration of older rocks by water.
But it was not clear how long liquid water persisted inside the crater, either as flash floods, filling the impact crater and drying up in the space of just a few years, or as a lake feed by groundwater for millions of years. The level of alteration that scientists see in the rock sampled by Perseverance suggests that water was present for a long time.
The rover will spend the next few weeks around Rochette to complete his investigations before moving to its next target, a series of ridges covered by sand dunes, boulders, and rock shards just 656 feet (200 meters) away and named South Séítah, Navajo meaning "amongst the sand."
Perseverance will collect rock samples, analyze their chemical properties, seal them into containers and leave them behind to be picked up at a later time. NASA plans to bring around 30 samples back to Earth in the 2030s, to be analyzed by instruments that are much more sophisticated than those that can be brought to Mars at present.
"These samples have high value for future laboratory analysis back on Earth,” said Mitch Schulte of NASA Headquarters, the mission’s program scientist. “One day, we may be able to work out the sequence and timing of the environmental conditions that this rock’s minerals represent. This will help answer the big-picture science question of the history and stability of liquid water on Mars.”
https://news.google.com/__i/rss/rd/articles/CBMieGh0dHBzOi8vd3d3LmZvcmJlcy5jb20vc2l0ZXMvZGF2aWRicmVzc2FuLzIwMjEvMDkvMTEvcm9jay1zYW1wbGVkLWJ5LW5hc2FzLXBlcnNldmVyYW5jZS1yb3Zlci1yZXZlYWxzLW1hcnMtYW5jaWVudC1wYXN0L9IBfGh0dHBzOi8vd3d3LmZvcmJlcy5jb20vc2l0ZXMvZGF2aWRicmVzc2FuLzIwMjEvMDkvMTEvcm9jay1zYW1wbGVkLWJ5LW5hc2FzLXBlcnNldmVyYW5jZS1yb3Zlci1yZXZlYWxzLW1hcnMtYW5jaWVudC1wYXN0L2FtcC8?oc=5
2021-09-11 16:12:14Z
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