Rock-hunting NASA rover reveals Martian crater's surprising geology


By Will Dunham

WASHINGTON (Reuters) – Core samples drilled by NASA’s Perseverance rover on the Martian floor are revealing the geology of a gaping crater scientists suspect could have harbored microbial life billions of years in the past, together with surprises concerning the nature of the rock current there.

The samples, obtained by the car-sized, six-wheeled robotic rover and saved for future transport to Earth for additional research, confirmed that rock from 4 websites inside Jezero crater is igneous – shaped by the cooling of molten materials. The rocks additionally bore proof of alteration via publicity to water, one other signal that chilly and arid Mars way back was heat and moist.

The scientists had thought the rock, shaped roughly 3.5 billion years in the past, could be sedimentary, shaped as mud and sand deposited in a lakebed.

“In reality, we discovered no proof of sedimentary rocks the place the rover explored the crater ground, regardless of the very fact we all know the crater as soon as held a lake and sediment will need to have been deposited. Those sedimentary deposits will need to have eroded away,” mentioned Caltech geochemist Kenneth Farley, lead creator of one in every of 4 research revealed within the journals Science and Science Advances describing the crater’s geology.

Perseverance arrived on Mars in February 2021 and has been busily working in Jezero crater since then, utilizing a collection of devices, as scientists probe whether or not Earth’s closest planetary neighbor ever possessed situations conducive to life.

It is gathering rock samples, concerning the dimension of blackboard chalk, in small tubes as a result of be retrieved by a spacecraft in 2033 and dropped at Earth for additional examination together with for biosignatures – indicators of life.

Jezero crater is 28 miles (45 km) broad, positioned simply north of the Martian equator. It seems the realm as soon as was ample with water and residential to a river delta, with river channels spilling over the crater wall to type a big lake. Scientists suspect the crater may have harbored microbial life, with proof maybe contained in lakebed or shoreline rock.

Perseverance is now accumulating samples within the delta space.

The crater’s igneous rocks had been discovered to have interacted with water, making new minerals and depositing salts, although this water apparently was both in low abundance or not current very lengthy – probably groundwater. But the water’s presence suggests this may need been a liveable surroundings on the time, the researchers mentioned.

“We collected samples that will probably be returned to Earth, and they need to present crucial proof of what sorts of organisms, if any, inhabited the Jezero crater ground rocks once they had been interacting with water,” mentioned Yang Liu, a planetary pattern scientist at NASA’s Jet Propulsion Laboratory and lead creator of one of many research.

The 4 samples had been drilled from two areas, one known as Seitah and the opposite Maaz. The Seitah rock seems to have shaped underground via sluggish cooling of a thick sheet of magma. The Maaz rocks could have cooled comparatively extra rapidly in an higher layer of underground magma or after a volcanic floor eruption. Either approach, any rock layer that after lined these areas has since eroded away, both from water or wind.

Liu mentioned the Seitah samples had been a coarse-grained igneous rock containing the mineral olivine, noting that three Martian meteorites discovered on Earth have an identical composition.

Examining the samples again on Earth could reveal when the rock was shaped and provides a firmer reply to when liquid water existed on the Martian floor. Liquid water is a key ingredient for all times.

“Understanding when, and for the way lengthy, the local weather situations on Mars allowed for the steadiness of liquid water is of central significance to the bigger questions that we are trying to deal with with this mission and pattern return – on whether or not and when life may have as soon as existed on early Mars, billions of years in the past,” mentioned geochemist and research co-author David Shuster of the University of California, Berkeley.

(Reporting by Will Dunhamk, Editing by Rosalba O’Brien)

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