HOUSTON: Ancient Mars was home to giant volcanoes capable of eruptions a thousand times more powerful than the one that shook Mount St. Helens in 1980, scientists have said.
The finding raises fresh questions about conditions on Mars in its early years, a time when scientists believe the planet was much more Earth-like with a thick atmosphere, warmer temperatures and water on its surface.
Major volcanic eruptions likely would have triggered climate shifts that toggled temperatures between cold spells when ash blocked sunlight and heat waves when greenhouse gases filled the skies, according to scientists.
Supervolcanoes may have made it more difficult for life to evolve on the planet’s surface, but underground steam vents and the release of water into the atmosphere also could have created niches for microbes to thrive, said Joseph Michalski of the Planetary Science Institute in Tucson, Arizona.
The discovery of supervolcanoes on Mars comes from analysis of images from a quartet of Mars orbiters over the past 15 years.
These types of volcanoes, also known as “caldera” volcanoes, are ancient, collapsed structures rather than steep, cone-shaped or domed mountains like Olympus Mons on Mars, a so-called shield volcano that stands nearly three times taller than Mount Everest.
“We know a lot about the volcanic history of Mars over the last 3 billion to 3.5 billion years, but that still leaves about 1 billion years before that over which we don’t really know anything about volcanism,” Michalski said.
“If early Mars saw a lot more explosive volcanism, then the features that are left from that don’t look like those shield volcanoes. That’s maybe why we didn’t see them,” Michalski said.
Scientists say supervolcanoes erupt with about 1,000 times the force of typical volcanoes. The eruption of Mount St. Helens in 1980 blasted the top off the mountain, killed 57 people and shot ash, steam, water and debris about 24,000 meters into the air.