Mars is making news again. I mean, when isn’t Mars making news these days? This time, field geologists have analyzed data taken from Curiosity at Gale Crater and determined that a megaflood occurred in ancient Martian history.

In a paper published in Nature Scientific Reports, researchers explain how this megaflood left behind familiar ripple structures in the crater that match ones we have on Earth. The flood was likely set off by a large meteor impact four billion years ago that unleashed massive amounts of ice stored in the subsurface of the red planet.

According to lead author Ezat Heydari: This case includes the occurrence of giant wave-shaped features in sedimentary layers of Gale crater, often called “megaripples” or antidunes that are about 30-feet high and spaced about 450 feet apart.

These features match antidunes formed by melting ice here on Earth around two million years ago. Per the press release: The most likely cause of the Mars flooding was the melting of ice from heat generated by a large impact, which released carbon dioxide and methane from the planet’s frozen reservoirs. The water vapor and release of gases combined to produce a short period of warm and wet conditions on the red planet.

Condensation formed water vapor clouds, which in turn created torrential rain, possibly planetwide. That water entered Gale Crater, then combined with water coming down from Mount Sharp to produce gigantic flash floods.

It’s generally accepted that Mars had water in the past, and that has led a lot of us to think life was once possible. All we can really do now is wait for Perseverance to arrive and see if it finds what we’re hoping for: evidence of that past life.

More Information

Cornell University press release 

“Deposits from giant floods in Gale crater and their implications for the climate of early Mars,” E. Heydari et al., 2020 Nov. 5, Nature Scientific Reports