An ancient volcanic eruption on the Red Planet made so much lava that it caused the entire planet to tip over. This remarkable finding, detailed in a study in the journal Nature, provides another startling instance of how volcanoes can change a world.
There have been some fairly powerful volcanic eruptions throughout Earths dramatic history. Some are violent, like the cataclysmic two-part eruption of part of the Yellowstone supervolcano 2.1 million years ago that interred much of North America in ash. Some are prolonged and deadly, like the outburst at the Siberian Traps thatcontributed towards the worlds worst mass extinction event, the Great Dying.
Its unlikely, however, that any volcanic eruption on Earth was powerful enough to cause the crust to collapse in on itself. Incredibly, this is precisely what happened on Mars thanks to the formation of a region called Tharsis.
A huge volcanic plateau near the Martian equator, Tharsis contains some of the largest volcanoes in the Solar system. Martian volcanoes tend to be of the shield variety, very similar in shape and behaviour to Earths Hawaiian shield volcanoes. These huge, exceedingly widebut relatively short animals tend to continuously and slowly erupt lava over exceedingly long periods of time , normally until the hotspot fueling them from below either dies or moves on.
Tharsis volcanoes were no exception to this, but the volume of erupted lava found in this region is staggering: it collectively weighs a billion billion tonnes. Tharsis as a whole is over 5, 000 kilometers( 3,100 miles) in width and 12 kilometers( 7.5 miles) thick. A 3.5 -billion-year-old eruption gradually forced this ginormous quantity of lava to the surface over the space of 2million years.
The formation of Tharsis caused at least a 20 -degree shift in the axial tilt of the Red Planet. Bouley et al ./ Nature
The Tharsis dome is enormous, especially in relation to the size of Mars. It’s an aberration, Sylvain Bouley, a geomorphologist from Universite Paris-Sud and lead writer of the study, said in a statement.
A previous analyse in 2010 demonstrated that if Tharsis was removed from Mars, the planet would change on its rotational axis to compensate for the sudden weight loss. Use computer simulations, Bouleys team worked out what Mars would have been like both before and soon after this massive volcanic eruption occurred.
The gargantuan motion of molten material from the depths to the surface temporarily flipped part of Mars upper geology: The solid crust of the planet swiveled around the partly-molten mantle layer beneath it. Incredibly, this chaotic, comparatively quick eruption of a vast volume of lava caused the entire planet to tilt downwards by 20 to 25 degrees.
In other terms, the geographical north and south poles were in a very different place from where they are today. If a similar shift happened on Earth, Paris would be in the Polar Circle, said Bouley. We’d find Northern Lights in France, and wine grapes would be grown in Sudan.
Previously unexplained features of the Martian surface construct much more sense in the interests of this research. For instance, sizeable underground reservoir of frozen ice on Mars are today oddly close to the warm equator. Now we know that, prior to the formation of Tharsis, these icy caches would have once resided under the frigid poles.