Evidence of ancient life may have been erased from parts MaRs, a new NASA study has shown.
Space agency Curiosity The rover made an astonishing discovery while exploring the clay-rich sedimentary rocks around its landing site in Gale Crater, a former lake formed after an asteroid collided with the Red Planet approximately 3.6 billion years ago.
Clay is a good indicator of the presence of life because it is usually created when rocky minerals weather and rot after contact with water – a key ingredient for life. It is also an excellent storage material for microbial fossils.
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But when Curiosity took two samples of ancient mudstone, a sedimentary rock containing clay, from sections of dried lake bottom dating from the same time and location (3.5 billion years ago and only 400 m apart), the researchers found that one the site contained only half of the expected amount of clay minerals. Instead, this patch contained more iron oxides are compounds that give Mars a rusty hue.
The team believes that brine is the culprit behind this geological extinction: super-saline water that seeped into mineral-rich clay layers and destabilized them, washing them away and wiping away stains from both geological and perhaps even biological records.
“We used to think that when these layers of clay minerals formed at the bottom of the lake in Gale Crater, they stayed so, preserving the point in time that they formed over billions of years,” said lead author Tom Bristow, a researcher at the Research Center Ames NASA in Mountain View, California, said in a statement… “But later the brines destroyed these clay minerals in some places – essentially setting a record for the rock.”
The rover completed its analysis by drilling through the layers of the Martian rock before using its chemical-mineralogical tool, known as the CheMin, to examine the samples.
According to the study authors, the process of chemical transformation in the sediment is called diagenesis, and it could create new life under Mars, even if it erased some evidence of old life on its surface. So even though old records of life may have been erased in brine spots, the chemical conditions caused by the influx of salt water could have allowed more life to appear in its place, scientists say.
“These are great places to look for evidence of ancient life and determine livability,” study co-author John Grotzinger, a professor of geology at California Institute of Technology, said in a statement. “While diagenesis can erase the signs of life in the original lake, it creates the chemical gradients necessary to sustain life below the surface, so we’re very happy we found this.”
The Curiosity mission to Mars began nine years ago, but the rover continued its exploration of the Red Planet well ahead of its original two-year mission schedule to establish Mars’ historical habitability. He is currently working in collaboration with the new Mars rover Perseverance, which landed in February 2021 and has been tasked with collecting rock and soil samples for a possible return to Earth. land…
The study by Curiosity not only showed how the Martian climate has changed, but also helped Perseverance determine which soil samples need to be collected to increase the chances of finding life.
“We learned something very important: there are some parts of the Martian rocks that are not so good for preserving evidence of the past and possible life of the planet,” – co-author Ashwin Wasawada, research scientist for the Curiosity project at NASA Jet Propulsion. A laboratory in California, the report said. “Fortunately, we find them close together in Gale Crater and can use mineralogy to determine which is which.”
The quest for life on Mars has been re-energized with new research that could triangulate the possible locations of six methane emissions detected by the Curiosity rover during its stay in Gale Crater. Living science reported… Since all of the methane in Earth’s atmosphere comes from biological sources, scientists are thrilled to find this gas on Mars.
The researchers published their findings on July 9 in the journal Science.
Originally published on Live Science.