\n\t\t\t\t\t\t\t\tNASA Uses Mineralogical Marker to Understand Ancient Martian Climate\t\t\t\t\t\t\t<\/h1>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n![\"\"](\"https:\/\/assets.science.nasa.gov\/dynamicimage\/assets\/science\/psd\/mars\/downloadable_items\/3\/8\/38884_mars-msl-gale-crater-mt-sharp-soil-layers-pia19912.jpg?w=2279&h=1127&fit=clip&crop=faces%2Cfocalpoint\")
<\/figure>\n<\/div>\n<\/div>\n<\/div>\n\n\n\nThis composite image looking toward the higher regions of Mount Sharp was taken on September 9, 2015, by NASA\u2019s Curiosity rover. In the foreground \u2014 about 2 miles (3 kilometers) from the rover \u2014 is a long ridge teeming with hematite, an iron oxide.\u00a0<\/figcaption><\/div>\n<\/div>\n\n\t\t\t\t\t\tCredits: <\/span>
\n\t\t\t\t\t\tNASA\/JPL-Caltech\/MSSS<\/span>\n\t\t\t\t\t<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nWhile NASA imagery has shown evidence of ancient rivers and lakes on Mars that transitioned to dry dunes, uncertainty remains over the timing of the environmental changes that may have contributed to these shifts. <\/p>\n
Now, data collected by NASA\u2019s Curiosity rover has revealed that individual crystals in the iron oxide hematite can be used as a mineralogical marker of changes to Mars\u2019 ancient climate. Because the shape and structure of these crystallites reflect the conditions \u2013 such as temperature and water presence \u2013 under which they were formed, they can serve as an indicator of when these changes occurred.<\/p>\n
Scientists studied 20 samples collected by Curiosity across various elevations throughout Gale Crater for a paper published Thursday in Science<\/a>. Gale Crater\u2019s walls reveal Mars\u2019 environmental history layer by layer, with deeper elevations capturing its earliest years. The team analyzed data from the rover\u2019s Chemistry and Minerology (CheMin) instrument and discovered that hematite showed different crystallite sizes at different elevations. They also discovered that goethite, a mineral that typically forms alongside hematite, was absent in samples from lower elevations but still present in samples from higher elevations. This suggests that warm groundwater might have remained for up to 4.7 million years in the deepest layers of Gale Crater and that during much of this time, these long-lived aquifers could have been potentially habitable.<\/p>\n\n\n\n![\"A](\"https:\/\/assets.science.nasa.gov\/dynamicimage\/assets\/science\/psd\/ares\/T_Peretyazhko_samples.jpg?w=2160&h=2156&fit=clip&crop=faces%2Cfocalpoint\")
<\/a><\/figure>\nThis image shows the 20 Curiosity drill samples from Gale Crater that were analyzed for this study.<\/div>\nCredit: NASA\/JPL-Caltech\/MSSS<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n\u201cWhat we found was that warm and wet conditions were present for extended periods in buried rocks, despite Mars\u2019 climate becoming colder,\u201d said Tanya Peretyazhko, co-first author of the study and planetary scientist in the Astromaterials Research and Exploration Science<\/a> division at NASA\u2019s Johnson Space Center in Houston. \u201cIt means that deep in those rocks, those warmer conditions could have made for habitable conditions for much longer periods of time, provided that other essential factors were present.\u201d<\/p>\nIron oxides are considered indicators of water activity because they form in its presence. This study shows that hematite can also be a marker of climate changes based on its crystallite sizes and structures, which change under different temperatures. The scientists found that hematite crystallites from higher elevations in Gale Crater were less than 10 nanometers in size, while crystallites from lower locations were generally larger, reaching up to 65 nanometers. These findings aligned with the observations that samples from higher elevations contained both hematite and goethite, while lower elevation samples lacked goethite.<\/p>\n
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<\/figure>\n<\/div>\n<\/div>\n<\/div>\n\n\t\t\t\t\t\tNASA\/JPL-Caltech\/MSSS<\/span>\n\t\t\t\t\t<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n
While NASA imagery has shown evidence of ancient rivers and lakes on Mars that transitioned to dry dunes, uncertainty remains over the timing of the environmental changes that may have contributed to these shifts. <\/p>\n
Now, data collected by NASA\u2019s Curiosity rover has revealed that individual crystals in the iron oxide hematite can be used as a mineralogical marker of changes to Mars\u2019 ancient climate. Because the shape and structure of these crystallites reflect the conditions \u2013 such as temperature and water presence \u2013 under which they were formed, they can serve as an indicator of when these changes occurred.<\/p>\n
Scientists studied 20 samples collected by Curiosity across various elevations throughout Gale Crater for a paper published Thursday in Science<\/a>. Gale Crater\u2019s walls reveal Mars\u2019 environmental history layer by layer, with deeper elevations capturing its earliest years. The team analyzed data from the rover\u2019s Chemistry and Minerology (CheMin) instrument and discovered that hematite showed different crystallite sizes at different elevations. They also discovered that goethite, a mineral that typically forms alongside hematite, was absent in samples from lower elevations but still present in samples from higher elevations. This suggests that warm groundwater might have remained for up to 4.7 million years in the deepest layers of Gale Crater and that during much of this time, these long-lived aquifers could have been potentially habitable.<\/p>\n \u201cWhat we found was that warm and wet conditions were present for extended periods in buried rocks, despite Mars\u2019 climate becoming colder,\u201d said Tanya Peretyazhko, co-first author of the study and planetary scientist in the Astromaterials Research and Exploration Science<\/a> division at NASA\u2019s Johnson Space Center in Houston. \u201cIt means that deep in those rocks, those warmer conditions could have made for habitable conditions for much longer periods of time, provided that other essential factors were present.\u201d<\/p>\n Iron oxides are considered indicators of water activity because they form in its presence. This study shows that hematite can also be a marker of climate changes based on its crystallite sizes and structures, which change under different temperatures. The scientists found that hematite crystallites from higher elevations in Gale Crater were less than 10 nanometers in size, while crystallites from lower locations were generally larger, reaching up to 65 nanometers. These findings aligned with the observations that samples from higher elevations contained both hematite and goethite, while lower elevation samples lacked goethite.<\/p>\n<\/a><\/figure>