The early climate of Mars was intermittently warm

Samples from the Jezero Crater, the landing site for NASA’s Mars 2020 mission, may help reveal evidence of climate change in the presence of Mars and possible signs of premortal life. Credit: NASA / JPL-Caltech / MSSS / JHU-APL

A new study that characterizes Mars’ lifelong climate has shown that in its early history, Mars was regularly warmed by volcanic activity and the influx of greenhouse gases from meteorites, but remained relatively cold during that period. And therefore revealed to offer opportunities and challenges for any microbial organism that may have emerged on the Red Planet. The study involved a team of scientists, including Dr. Joel Hurowitz of Stony Brook University. The survey results are Nature Geoscience..

The author, led by Dr. Robin Wordsworth of Harvard University, wrote that the geology of Mars is characterized by past evidence of temporary surface liquid water, and geochemistry goes from slower and damp to drier. Intermittent transitions, and more oxidative surface conditions. In the “Integrated Model of Temporary Warming, Oxidation, and Geochemical Successions in Early Mars,” the researchers teamed up on greenhouse gas reductions and hydrogen to investigate the conditions responsible for diverse geological observations. We present a new model that incorporates random injection of oxidation by escape.

“Mars was warmed intermittently when its atmospheric composition changed due to volcanic activity and the influx of gases from meteorite impactors. These climate optimizations allowed water to flow across surfaces, such as rivers and rivers. Rocks and minerals associated with lakes and water on Mars have formed, “explains Hurowitz, an associate professor of earth sciences at the School of Arts and Sciences at Stoneybrook University.

Hurowitz is a member of the research team working on the NASA Mars 2020 Mission Perseverance Rover and one of the scientists working on the PIXL (X-ray Rock Chemistry Planetary Instrument) mounted on Rover’s arm.

“This treatise proposes a model of Martian climate change, which can be tested with rock chemistry and mineralogy measurements by PIXL and Jezero Crater Perseverance Rover,” says Hurowitz.

Climate models predict that early Mars is generally cold, with average annual temperatures below 240 degrees Fahrenheit (minus 28 degrees Fahrenheit). When peak reduced outgassing and background carbon dioxide levels are high enough, the planet exhibits warm enough intervals to degrade crater walls, form a network of valleys, and create features of other rivers / lakes. ..

The authors also write that the model also predicts the temporary accumulation of oxygen in the atmosphere. This can explain the occurrence of oxide mineral species such as manganese oxide observed in the Gail Crater by Curiosity Rover. They also found that large-scale temporal changes in planetary surface mineralogy dramatically delayed planetary oxidation, reduced groundwater availability, and surface sulfate relocation and thermochemical destruction. It points out that it can be explained by the combined result of the reduction of meteorite impactor flux.

The authors point out that the Earth is the only planet in the current solar system that has an oxygen-rich atmosphere. This suggests that oxygen may serve as a biomarker gas in the search for evidence of life on exoplanets. But they write: “Our model predicts a long-lived, relatively oxygen-rich atmosphere in the middle of Martian history, without the need for the presence of life. This is only the detection of oxygen, some It indicates that it can be a “false positive” for life. Status.

“Because prebiotic chemistry does not occur in highly oxidized environments, this task imposes constraints on the length and location of life that can occur and survive early on Mars.”

Although they suggest that the climate model of the early Martian environment “suggests the opportunity for the emergence of life at warm and moist intervals, where reducing conditions would have favored prebiotic chemistry. Frequent and over time, the intervals between cold and dry oxidative environments increase. ”

Planetary scientists have found evidence of a diminished atmosphere on ancient Mars

For more information:
Robin Wordsworth et al. Combined model of temporary warming, oxidation, and geochemical succession in early Mars, Nature Geoscience (2021). DOI: 10.1038 / s41561-021-00701-8

Courtesy of Stony Brook University

Quote: The early climate of Mars is intermittently warm (March 9, 2021), March 9, 2021 Obtained from.

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