WASHINGTON D.C. — The Perseverance Rover on Mars might have stumbled upon the oldest rocks people have ever seen and, presumably, proof of a brand new setting that historic Martian organisms might have inhabited, in the event that they ever existed.
“That is actually one of the thrilling issues that this mission goes to do, is to be taking a look at rocks that have been fashioned so early within the historical past of the photo voltaic system,” mentioned Caltech geochemist Kenneth Farley throughout a December 12 information briefing at a gathering of the American Geophysical Union. “Nearly the daybreak of the photo voltaic system.”
Presumably the oldest rocks we’ve seen
For many of its mission, Perseverance has been poking round inside Jezero Crater, probing and sampling rocks which might be most likely about 3.7 billion years outdated (SN: 2/17/23). The rocks on the rim, nonetheless, are most likely a lot older, having been uplifted by the impression that created the crater.
On December 11 — following a slippery, three-month-long, 500-meter climb from the crater ground — the robotic explorer lastly surmounted that crater’s rim, after weeks of finding out the excessive space’s geology. And all that exploration seems to have paid off.
“The rocks that we are actually exploring are seemingly older than 4 billion years,” mentioned Farley, who can also be venture scientist for the Mars 2020 Mission that introduced the rover to the planet. “These are amongst the oldest rocks within the photo voltaic system, and so they’re older than any rocks that exist on Earth.” A part of the explanation for that’s that a lot of Earth’s historic floor has been destroyed at subduction zones, the place one tectonic plate plunges beneath one other to descend into the mantle (SN: 1/13/21).
On the high of the crater, Perseverance traveled via an space often known as the Pico Turquino Hills, the place it captured photos of quite a few outcrops. “What we present in these comparatively small outcrops is that the rocks are extraordinarily numerous, and it seems that every one of many hills that make up the Pico Turquino Hills have a definite assemblage of largely igneous minerals, with some alteration by water,” Farley mentioned. “These are seemingly items of the earliest crust of Mars.”
Devices aboard Perseverance can’t exactly date the rocks. As an alternative, researchers are basing their age estimates on their present understanding of the crater’s formation and Mars’ historical past. “They’re our greatest estimates, however they’re simply estimates,” Farley mentioned. “This is without doubt one of the the explanation why we need to do pattern return.”
If the newly encountered Martian rocks are actually that outdated, they might comprise details about how rocky planets like Mars and Earth advanced of their infancy (SN: 3/16/17). “For us to grasp how rocky planets behave in that first, say, half a billion years, [we] can’t do it from Earth,” Farley mentioned.
A brand new potential setting for Martian life
Historical rocks weren’t all that Perseverance discovered within the Pico Turquino Hills. The rover additionally got here throughout proof of a totally new liveable setting for doable Martian life (SN: 7/15/24): a subject of “sensible white, cantaloupe-sized [stones], and the devices aboard the rover verify that these cobbles are pure quartz,” Farley mentioned. “This has by no means been seen earlier than” on Mars.
Quartz varieties in locations the place scorching fluids flow into via rocks, and generally at temperatures which might be liveable. These rocks might have fashioned in a setting akin to a scorching spring, and we all know these environments can help life on Earth, so maybe one thing comparable as soon as existed on Mars, Farley mentioned. “This can be a probably liveable surroundings that’s completely completely different from the liveable environments that Perseverance investigated on the crater ground.”
In line with Farley, the purpose is to now seek for quartz the place it’s nonetheless embedded within the Martian floor, so it may be sampled. “Neither our drill nor our abrader can really function on such unfastened, [cobblestone-sized rocks],” Farley mentioned. “The rock would simply transfer out of the way in which if we attempt to work on it.” Discovering easier-to-access quartz might additionally assist researchers higher perceive how the mineral matches into the remainder of the Martian rock file.
Subsequent cease, Witch Hazel Hill
Shifting on from the Pico Turquino Hills, Perseverance will spend the subsequent six months exploring an space known as Witch Hazel Hill. Situated away from the crater, the rocks at Witch Hazel Hill must be extra consultant of the geology of the broader area past, mentioned planetary scientist and geologist Candice Bedford of Purdue College in West Lafayette, Ind., on the information briefing.
What’s extra, NASA’s Mars orbiters have already recognized in depth outcropping of layered rocks at Witch Hazel Hill. “As geologists we love layered outcrops,” Bedford mentioned. “For us, each layer preserved is like, as we glance down via that, it’s like turning a [page in the book] of Martian historical past.”
