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Floods of unimaginable size once crossed the Gale crater on the equator of Mars about 4 billion years ago.
This discovery suggests the possibility that life may have existed there, according to data collected by NASA’s Curiosity rover and analyzed in a joint project by scientists at Jackson State University, Cornell University, the Jet Propulsion Laboratory and the University of Hawaii.
The research, “Deposits from Giant Floods in Gale Crater and Their Implications for the Climate of Early Mars,” was published November 5 in Scientific Reports.
The furious mega flood – likely caused by the heat of a meteor impact, which released the ice stored on the Martian surface – created giant ripples that are telltale geological structures familiar to scientists on Earth.
“We identified megafloods for the first time using detailed sedimentological data observed by the Curiosity rover,” said co-author Alberto G. Fairén, a visiting astrobiologist at the College of Arts and Sciences. “The deposits left by the megafloods had not previously been identified with the data from the orbiter.”
As in the case of the Earth, geological features, including the work of water and wind, have been frozen in time on Mars for about 4 billion years. These features convey processes that have shaped the surface of both planets in the past.
This case includes the presence of gigantic wave-shaped features in the sedimentary layers of the Gale crater, often called “megaripples” or antidunes that are about 30 feet tall and spaced about 450 feet apart, according to the lead author. Ezat Heydari, a physics professor at Jackson State University.
Antidunes are indicative of megafloods flowing to the bottom of Mars’ Gale crater about 4 billion years ago, which are identical to features formed by the melting of ice on Earth about 2 million years ago, Heydari said.
The most likely cause of the flooding of Mars was the melting of the ice due to the heat generated by a large impact, which released carbon dioxide and methane from the planet’s frozen reservoirs. Water vapor and gas release combined to produce a brief period of warm, humid conditions on the red planet.
The condensation formed clouds of water vapor, which in turn created torrential rains, possibly all over the planet. That water entered the Gale Crater, then combined with the water flowing down from Mount Sharp (in the Gale Crater) to produce gigantic flash floods that deposited gravel ridges in the Hummocky Plains unit and band formations of ridges and depressions in the striated unit.
The science team of the Curiosity rover has already established that Gale Crater once had persistent lakes and streams in the ancient past. These long-lived bodies of water are good indicators that the crater, as well as Mount Sharp within it, were capable of supporting microbial life.
“Early Mars was an extremely active planet from a geologic point of view,” Fairén said. “The planet had the necessary conditions to support the presence of liquid water on the surface and on Earth, where there is water, there is life.
“So in the beginning Mars was a habitable planet,” he said. “Was it inhabited? That’s a question the next Perseverance rover … will help answer.”
Perseverance, launched from Cape Canaveral on July 30, will reach Mars on February 18, 2021.
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Joining Fairén and Heydari on paper are Jeffrey F. Schroeder, Fred J. Calef, Jason Van Beek, and Timothy J. Parker, of NASA’s Jet Propulsion Laboratory; and Scott K. Rowland, University of Hawaii.
Data and funding were provided by NASA, Malin Space Science Systems, the Jet Propulsion Laboratory and the European Research Council.
Astrobiology
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