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 historical Martian organisms may have inhabited, in the event that they ever existed.
“That is actually one of the crucial thrilling issues that this mission goes to do, is to be rocks that had been fashioned so early within the historical past of the photo voltaic system,” stated Caltech geochemist Kenneth Farley throughout a December 12 information briefing at a gathering of the American Geophysical Union. “Virtually the daybreak of the photo voltaic system.”
Probably 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been poking round inside Jezero Crater, probing and sampling rocks which might be most likely about 3.7 billion years outdated (SN: 2/17/23).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, nevertheless, are most likely a lot older, having been uplifted by the influence 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 at the moment are exploring are possible older than 4 billion years,” stated Farley, who can be undertaking 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 rationale for that’s that a lot of Earth’s historical 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 prime of the crater, Perseverance traveled by an space often known as the Pico Turquino Hills, the place it captured photographs 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 stated. “These are possible items of the earliest crust of Mars.”
Devices aboard Perseverance can not 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 stated. “This is among the the reason why we wish to do pattern return.”
If the newly encountered Martian rocks are actually that outdated, they might include details about how rocky planets like Mars and Earth developed of their infancy (SN: 3/16/17). “For us to know how rocky planets behave in that first, say, half a billion years, [we] can’t do it from Earth,” Farley stated.
A brand new potential setting for Martian life
Historic rocks weren’t all that Perseverance discovered within the Pico Turquino Hills. The rover additionally got here throughout proof of a very new liveable setting for doable Martian life (SN: 7/15/24): a area of “sensible white, cantaloupe-sized [stones], and the devices aboard the rover affirm that these cobbles are pure quartz,” Farley stated. “This has by no means been seen earlier than” on Mars.
Quartz varieties in locations the place sizzling fluids flow into by rocks, and generally at temperatures which might be liveable. These rocks might have fashioned in a setting akin to a sizzling spring, and we all know these environments can assist life on Earth, so maybe one thing related as soon as existed on Mars, Farley stated. “This can be a probably liveable setting that’s completely totally different from the liveable environments that Perseverance investigated on the crater ground.”
Based on Farley, the objective 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 truly function on such unfastened, [cobblestone-sized rocks],” Farley stated. “The rock would simply transfer out of the best way if we attempt to work on it.” Discovering easier-to-access quartz may additionally assist researchers higher perceive how the mineral suits into the remainder of the Martian rock file.
Subsequent cease, Witch Hazel Hill
Transferring 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 needs to be extra consultant of the geology of the broader area past, stated 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 stated. “For us, each layer preserved is like, as we glance down by that, it’s like turning a [page in the book] of Martian historical past.”
