Geological discoveries show the conditions when life arose on Earth – and possibly on Mars
WEST LAFAYETTE, Ind. — The accepted landscape of Mars is red rocks and craters as far as the eye can see. That’s what scientists expected when they landed the rover Perseverance in Jezero Crater, a site chosen for the crater’s history as a lake and as part of a rich river system, back when Mars had liquid water, air and magnetic field.
What the rover found once on the ground was surprising: Instead of the expected sedimentary rocks – washed by rivers and accumulated at the bottom of the lake – many of the rocks were naturally volcanic. Specifically, it’s made up of large grains of olivine, the clay’s less gem-like version of peridot that paints many of Hawaii’s beaches dark green.
Planetary scientists Roger Wiens, professor of earth, atmospheric, and planetary sciences, and Briony Horgan, associate professor of earth, atmospheric, and planetary sciences, in Purdue’s College of Science, were instrumental in the discovery and analysis of this data, was recently published in a set of papers in the journals Science and Science Advances.
Briony Horgan, Purdue University associate professor of planetary science, inside the Mars Rover Operations Center in Purdue’s Delon and Elizabeth Hampton Hall of Civil Engineering. Horgan helped select Jezero Crater as the landing site for Endurance. His expertise in geology helped put the rover’s discoveries in context. (Credit: Purdue University photo/Rebecca McElhoe) Download image
Wiens led the design and construction of Perseverance’s SuperCam, which helps in analyzing rock samples and determining their type and origin. Horgan helped select Jezero Crater as the rover’s landing site and is now using Perseverance’s Mastcam-Z cameras to put its discoveries into geological context.
“We’re starting to realize that these layers of igneous rocks that we’re seeing look different than the igneous rocks that we have today on Earth,” Wiens said. “They are very similar to the igneous rocks of the Earth in the early part of its existence.”
The rocks and lava examined by the rover on Mars are nearly 4 billion years old. Rocks that are ancient exist on Earth but are remarkably weathered and battered, thanks to the active tectonic plates of the Earth as well as the weathering effects of billions of years of air, water and life. On Mars, these rocks are clean and easier to analyze and study.
Understanding the rocks on Mars, their evolution and history, and what they reveal about the history of conditions on the planet Mars will help researchers understand how life arose on Mars and how it compares. of early life and conditions on the ancient Earth.
Roger Wiens, associate professor of planetary science at Purdue University and Mars rover expert at Purdue University with a topographical model of Mars and a photo of the rover Curiosity. He is the principal investigator of Perseverance’s SuperCam team and Curiosity’s ChemCam team. (Credit: Purdue University photo/John Underwood) Download image
“One of the reasons we don’t have a good understanding of where and when life began on Earth is because those rocks are mostly gone, so it’s very difficult to reconstruct what the ancient environments were like. Land,” Horgan said. “The rocks that Perseverance surrounds in Jezero have more or less been sitting on the surface for billions of years, waiting for us to come and see them. That’s one of the reasons that Mars is an important laboratory for understanding the early solar system.
Scientists can use the conditions on early Mars to help extrapolate the environment and conditions on Earth around the same time that life began. Understanding how, and under what conditions, life began will help scientists know where to look for it on other planets and moons, as well as lead to a deeper understanding of biological processes here. Earth.
Finding life is one of the main goals of Endurance and one of the reasons it landed in Jezero Crater in the first place. Discovering the potential for habitable environments in something as inhospitable as an old lava flow in Jezero Crater raises hopes for what lies in the sedimentary rocks currently being explored in mission.
“We’re excited to see better results regarding organic and ancient habitat environments,” Horgan said. “I think this really sets the stage for Mars to be this watery, habitable place, and all the samples we’re bringing back will help us understand the history of ancient microbial life on Mars.”
The equipment and innovative instruments help the rover fulfill its mission in a way that no other rover has ever done, emphasizing the need to land on the planet so that scientists can investigate and understand what is really going on.
“From orbit, we look at these rocks and say, ‘Oh, they have beautiful layers!’ So we think these are sedimentary rocks,” Horgan said. “And it wasn’t until we got really close and looked at them, at the millimeter scale, that we understood that these are not sedimentary rocks. It used to be lava. It was a big moment when we found that out on the ground, and really showed why we need this kind of exploration. The tools on the rover are important because it’s impossible to understand the origin of these rocks until we get up close and use all our amazing microscopic instruments to look at them.
More than 40 co-authors are listed on the suite of papers from national and international facilities, including NASA’s Jet Propulsion Lab and the Los Alamos National Laboratory.
Horgan, Wiens and their colleagues at Purdue will continue to analyze and guide Perseverance’s discoveries and insights into the history of Mars, just as Purdue scientists continue to help analyze rocks from Apollo moon missions that put the first and last men on the moon.
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Media contacts: Brian Huchel, bhuchel@purdue.edu,
Brittany Steff, bsteff@purdue.edu
Sources: Briony Horgan briony@purdue.edu
Roger Wiens rwiens@purdue.edu
Papers
Compositionally and density stratified igneous terrain in Jezero crater, Mars.
Advances in Science
10.1126/sciadv.abo3399
The abstract and author list are available online.
Aqueous altered igneous rocks sampled on the floor of Jezero crater, Mars
Science
10.1126/science.abo2196
The abstract and author list are available online.
An olivine cumulate outcrop on the floor of Jezero crater, Mars
Science
10.1126/science.abo2756
The abstract and author list are available online.
