TL;DR: A University of Iowa geologist working with NASA's Perseverance rover helped identify corundum — a ruby- and sapphire-family mineral — in small white crystals in Jezero crater.
An Iowa lab joins a Mars find
A University of Iowa geology professor working with NASA helped discover a rare mineral in Jezero crater on Mars, according to The Daily Iowan.
The researcher is Valerie Payré, an assistant professor in the School of Earth, Environment, and Sustainability, reporting by The Daily Iowan identifies her as a planetary geologist studying the evolution of planetary bodies.
Payré has been working on the Mars 2020 rover team, The Daily Iowan reports, and her team uses a rover named Perseverance to analyze samples from the planet.
In that university role, Payré is a co-investigator on the NASA-funded SuperCam instrument team using the Perseverance rover to explore Mars, according to the University of Iowa College of Liberal Arts and Sciences.
The work centers on Jezero crater, where Perseverance is analyzing Martian samples and outcrops.
What Perseverance picked up
Recently, the rover collected a sample of small white crystals and identified a mineral called corundum, The Daily Iowan reports.
The crystals were described as small white crystals and, elsewhere in the same reporting, as small white pebbles whose source remains under investigation.
A small amount of corundum was found, according to the University of Iowa College of Liberal Arts and Sciences, which cautions that the quantity detected is limited.
The rover's analysis used laser-based examination of ordinary-looking rocks, an approach described in supporting technical summaries of the Perseverance work.
Three rocks identified by Perseverance were named Hampden River, Coffee Cove, and Smiths Harbour in those supporting summaries.
Those three rocks were described as dominated by plagioclase, a silicate mineral.
The corundum grains themselves were described as tiny.
Why corundum matters
Corundum is a mineral composed of aluminum and oxygen, The Daily Iowan reports.
On Earth, it makes up the family of rubies and sapphires, The Daily Iowan reports.
The University of Iowa College of Liberal Arts and Sciences likewise describes corundum as a mineral in the same family as rubies and sapphires.
In crystalline terms, supporting summaries describe corundum as the crystalline form of aluminum oxide.
It forms on Earth with a combination of conditions of pressure, temperature, and fluids, The Daily Iowan reports.
Payré said this is an incredibly uncommon combination on Mars, The Daily Iowan reports.
The chemistry is demanding because corundum formation calls for abundant aluminum and limited silicon, a balance summarized as aluminum-rich and silicon-poor chemistry.
That balance is difficult to achieve on Mars because of the prevalence of silicate minerals, supporting summaries explain.
The plagioclase-dominated character of the Hampden River, Coffee Cove, and Smiths Harbour rocks makes the result especially striking to the team.
A first for the Martian surface
“It’s the first time we’re observing it at the surface of Mars, so we were not expecting it at all,” Payré said, as quoted by the University of Iowa College of Liberal Arts and Sciences.
The Daily Iowan likewise quotes Payré calling the result unexpected and explaining that the team is now working through what produced it.
“It’s unexpected, and so now we are trying to see what happened and that complexifies even more the geology of Mars,” Payré said, as quoted by The Daily Iowan.
The same report quotes her adding that the result remains positive even as it adds complexity.
The first-at-the-surface framing is central to why Iowa and rover-team scientists treated the white-crystal analysis as significant.
A small amount was found, so discussion of future mining remains premature, according to the University of Iowa College of Liberal Arts and Sciences.
The college states that it is too early to say whether there is future potential for mining gems on the Red Planet.
The leading explanation: an ancient impact
Payré's team's current theory is the impact that formed the Jezero crater could have cultivated the necessary conditions to form corundum, The Daily Iowan reports.
Large impacts can generate extreme heat and pressure, conditions compared in supporting summaries to those that form metamorphic minerals deep within Earth's crust.
That comparison helps explain why an impact basin is now being examined as a possible mineral-forming environment.
However, most theories in geology tend to brush the effects of impact processes under the rug and instead focus on other aspects of the subject, The Daily Iowan reports.
“With this discovery, we understand that impacts have a big effect on the geology of Mars, and we didn’t think of this,” Payré said, as quoted by The Daily Iowan.
The evidence cited for an impact connection is circumstantial but specific: tiny grains, recovery on the crater's rim, and proximity to impact breccias.
Supporting summaries also note evidence of past hydrothermal activity in Jezero, which may have helped shape the needed fluid chemistry.
Interaction of fluids with rocks may have contributed to the aluminum-rich, silicon-poor chemistry, those summaries state.
Other possibilities still on the table
Researchers have not settled on a single formation path, with magma activity and interactions between rocks and hot fluids also listed among potential scenarios.
Magma activity is one alternative because Jezero's setting includes volcanic features and igneous material that can supply heat.
Hot-fluid alteration is another alternative because fluids can move elements and alter the local chemistry around existing minerals.
The impact hypothesis is currently described as the team's leading theory, not a final determination, The Daily Iowan reports.
Ultimately, Payré and her team will continue working to try to either prove or disprove current theories about Mars and Earth, The Daily Iowan reports.
That prove-or-disprove framing underscores that formation models remain under test.
Why Mars history helps Earth history
Learning that impact processes could have made such a change on Mars is pushing Payré and her team to rethink some common theories about Earth and how it was formed, The Daily Iowan reports.
Payré says this information is useful when thinking about Earth's geology because it is impossible to find rocks as old as this on Earth due to shifting tectonic plates, The Daily Iowan reports.
“We don’t know what Earth looked like 4 billion years ago because we don’t have any rock record from that time,” Payré said, as reported by The Daily Iowan.
“On Mars we do,” she added in the same report.
Common geological theory on plate tectonics is tentative, The Daily Iowan reports.
Researchers still are not sure how plate tectonics actually started, The Daily Iowan reports.
Understanding plate tectonics is crucial to understanding other processes that are essential for life on Earth, such as the carbon cycle and the water cycle, The Daily Iowan reports.
An implication that processes involving impact, something not widely thought of as highly formative for Earth's crust and plate tectonics, could transform the way humans think about Earth and its geological history, The Daily Iowan reports.
What happens next on the crater rim
Payré is still working with her team to learn more, The Daily Iowan reports.
Right now, Perseverance is traveling to locations in the crater where the team could see larger white rocks that could be the source of the original white pebbles, The Daily Iowan reports.
If the rover finds such a rock, the team will work on analyzing them to see if they contain corundum or not, The Daily Iowan reports.
Researchers emphasize the need to locate the outcrop from which these float rocks originated.
They also emphasize the value of retrieving a core sample from that outcrop and bringing material back to Earth for more comprehensive analysis.
With Perseverance healthy and its mission extended, Payré hopes the rover can continue helping scientists investigate Mars and its history for years to come, according to the University of Iowa College of Liberal Arts and Sciences.