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\n Media contact:<\/strong> Brittany Steff, bsteff@purdue.edu<\/a> <\/p>\n <\/div>\n
WEST LAFAYETTE, Ind. \u2014 Sometimes scientists must dig and work and sweat to make scientific discoveries. And sometimes a robot rolls over a rock that turns out to be a revelation.<\/p>\n\n\n\n
That\u2019s what happened when Mars exploration expert Roger Wiens, professor of earth, atmospheric, and planetary sciences in the College of Science<\/a> at Purdue University, had NASA\u2019s Perseverance rover shoot its laser at some oddly pale rocks lying on the Martian surface \u2014 and discovered that they are composed of unusually high aluminum associated with the mineral kaolinite. That was interesting on its own, but what made the discovery fascinating is that this mineral typically forms only in very warm and wet environments. The discovery, published by Wiens and his team in Nature Communications Earth & Environment<\/a>, suggests that Mars may have been warmer, wetter and weirder than scientists suspected.<\/p>\n\n\n\n \u201cOn Earth, these minerals form where there is intense rainfall and a warm climate or in hydrothermal systems such as hot springs. Both environments are ideal conditions for life as we know it,\u201d Wiens said. \u201cThese minerals are what\u2019s left behind when rock has been in flowing water for eons. Over time, the warm water leaches away all the elements except those that are really insoluble, leaving behind what we found on Mars. It\u2019s fascinating. It\u2019s unexpected on a cold, dry planet like Mars.\u201d<\/p>\n\n\n\n Wiens has worked on and with Mars rovers for decades and literally gave Perseverance its head. The blocky projection on top of the rover, which superficially resembles a quadruped\u2019s neck and head, is SuperCam, an instrument developed by an international team of researchers and engineers that Wiens led before coming to Purdue. SuperCam is the result of a collaboration with Los Alamos National Laboratory and the French Institut de Recherche en Astrophysique et Plan\u00e9tologie, and is funded by NASA and the Centre National d\u2019\u00c9tudes Spatiales in France.<\/p>\n\n\n\n The instrument uses a suite of techniques to analyze the Martian surface. Now Wiens leads the research team that uses SuperCam\u2019s tools to make discoveries on Mars.<\/p>\n\n\n\n Researchers observed the small, pale pebbles in the Martian soil the first day the rover landed. But the rover team was too busy working on other things to check out the odd little rocks.<\/p>\n\n\n\n Eventually, scientists observed some larger rocks of a similar color lying on the surface, not part of the bedrock beneath the rover\u2019s wheels. Geologists call these loose rocks \u201cfloat rocks\u201d because they are \u201cfloating\u201d above the bedrock \u2014 they are out of place, away from where they were formed. Once SuperCam\u2019s laser analyzed the rocks, the team members realized they had an interesting discovery.<\/p>\n\n\n\n \u201cThese rocks are very different from anything we\u2019ve seen on Mars before,\u201d Wiens said. \u201cThey\u2019re enigmas.\u201d<\/p>\n\n\n\n The team proceeded to analyze the rocks more deeply for insights into their composition and structure. Two researchers from Wiens\u2019 team led the study. Candice Bedford, research scientist, and Clement Royer, postdoctoral researcher, had just arrived at Purdue when the discovery was made, and they developed the detailed study, along with Briony Horgan, professor of planetary science in the College of Science, and several of her and Wiens\u2019 students. The team found more than 4,000 of these white rocks and pebbles scattered across the surface.<\/p>\n\n\n\n The mineral that makes up many of these pale rocks is called kaolinite. What especially excites the scientists is that it typically forms in environments that are warm, wet and hospitable to some forms of microbial life. On Earth, it is found in sedimentary deposits resulting from ancient soils and coastlines and intense hydrothermal environments, and the mineral is quite soft. On Mars, the rocks are white but not as soft, possibly due to other processes that may have hardened the rocks.<\/p>\n\n\n\n These rocks were also found to contain spinel, likely aluminum spinel, which can form either in an igneous or a metamorphic environment, and can be found as remnants in sedimentary rocks. Wiens and his team are unsure which happened here \u2014 whether the spinel formed from the kaolinite or the kaolinite formed around the spinel.<\/p>\n\n\n\n \u201cThe big questions about Mars are about water,\u201d Wiens said. \u201cHow much water was there? How long was there water? Given how cold and dry Mars is now, where did all that water go? As a mineral, kaolinite has a lot of water bound up in its structure. It\u2019s possible that a lot of the water is still there, on Mars, bound up in the minerals.\u201d<\/p>\n\n\n\n \u201cAlthough we have not seen these rocks \u2018in place\u2019 in bedrock with the rover, and we\u2019re not sure where these float rocks came from, from orbiting satellites we know that there are kaolinite-rich rocks in Jezero crater\u2019s rim,\u201d said Bedford, co-lead author of this research. \u201cInvestigating these rocks in place will help us test our hypotheses on how the rocks formed, how they relate to Mars\u2019 ancient environment and the habitability of the planet in the past. We are keeping our eyes wide open looking for the source of these rocks now that Perseverance is exploring the crater rim.\u201d<\/p>\n\n\n\n Those insights might help guide humans to the first true signs of ancient extraterrestrial life, since, as far as we can tell, life can\u2019t exist without water. By studying Mars\u2019 present, scientists uncover clues to its \u2014 and Earth\u2019s \u2014 past, as well as insight into where to look for hints of life in the future.<\/p>\n\n\n\n Purdue University is a public research university leading with excellence at scale. Ranked among top 10 public universities in the United States, Purdue discovers, disseminates and deploys knowledge with a quality and at a scale second to none. More than 107,000 students study at Purdue across multiple campuses, locations and modalities, including more than 58,000 at our main campus in West Lafayette and Indianapolis. Committed to affordability and accessibility, Purdue\u2019s main campus has frozen tuition 13 years in a row. See how Purdue never stops in the persistent pursuit of the next giant leap \u2014 including its comprehensive urban expansion, the Mitch Daniels School of Business, Purdue Computes and the One Health initiative \u2014 at https:\/\/www.purdue.edu\/president\/strategic-initiatives<\/strong><\/a>. <\/p>\n\n\n \n Media contact:<\/strong> Brittany Steff, bsteff@purdue.edu<\/a> <\/p>\n <\/div>\n Rock hound rover<\/h2>\n\n\n\n
Once upon a blue Mars<\/h2>\n\n\n\n
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