In research by a team led by Planetary Science Institute‘s own Alexis Rodriguez, there is new evidence that asteroids impacted ancient Martian glaciers and the resulting splash, for lack of a better term, drove water and dust into the Martian atmosphere. According to Rodriguez: Something unique happened on Mars during this early phase in its history – most of the planet’s impact basins formed. The formation of these gigantic structures, hundreds to two thousand kilometers in diameter, would have produced extremely powerful winds and would have also most likely triggered transient climate change conducive to rainfall. The winds could have dislodged from the surface vast volumes of dust that existed when the impacts occurred, resulting in dust-laden atmospheric conditions. We suggest that when rainfalls happened, large amounts of the dust were removed from suspension to be redeposited as thick sedimentary units.
Rodriguez goes on to explain: An interesting implication of the muddy rain hypothesis is that this process could have emplaced enormous volumes of wet sediments over the planet’s extremely cold surface environments. In the likely presence of salts, the water-soaked mud might have produced immense aquifers with low-temperature freezing brines.
Put another way, this process could have created reservoirs of salty liquid water while at the same time building up immense mudstones that we see today.
This work has a lot of cool implications for Mars’s former water cycle and even potential habitability. We’re going to invite the team members who did this work to come on as guests so they can explain this work in their own words. For now, you can check out their paper in the journal Nature Scientific Reports.
“The Oldest Highlands of Mars May Be Massive Dust Fallout Deposits,” J. Alexis P. Rodriguez et al., 2020 June 25, Nature Scientific Reports