Volcanoes are remarkably common. They act as pressure release valves to rocky worlds, as magma, ice, and other materials escape from their heated interiors like steam from an Instant Pot. Not all volcanoes are made the same, however, and as we look across our world and others we are realizing that super-eruptions that rewrote entire regions can occur. 

On Mars, researchers led by Patrick Whelley have documented a history of explosive eruptions on the Arabia Terra that blanketed the region in layers of ash and aluminum-rich minerals. This ash is 100-1,000 meters deep and is likely the result of between 1,000 and 2,000 eruptions that occurred over 500 million years. According to Whelley: Each one of these eruptions would have had a significant climate impact — maybe the released gas made the atmosphere thicker or blocked the Sun and made the atmosphere colder. Modelers of the Martian climate will have some work to do to try to understand the impact of the volcanoes.

Most fascinating to me is the timing of this volcanism. According to their paper, it took place during the late Noachian and early Hesperian periods. The Noachian period was when Mars was getting bombarded with small bodies like asteroids and comets, and the atmosphere of Mars is thought to have been thicker and warmer than it is today. As Mars transitioned from the Noachian period to the Hesperian, the world underwent widespread volcanic activity and experienced canyon-carving flood events. These eruptions, and their climate-changing ash, would have been part of the geophysics that shaped this warm, wet, and catastrophic period in Mars history – the part of its history many of us are most interested in understanding.

Now, I want a time machine. Failing that, more rovers, please? There are volcanoes to explore and geologic histories to study.

More Information

NASA Goddard press release

“Stratigraphic Evidence for Early Martian Explosive Volcanism in Arabia Terra,” Patrick Whelley et al., 2021 July 16, Geophysical Research Letters