Monster volcano gave Mars extreme makeover: study

March 2, 2016 by Laurence Coustal, Marlowe Hood
A high-resolution stereo camera-obtained image released on September 26, 2008 by the European Space Agency shows the Mangala Fos
A high-resolution stereo camera-obtained image released on September 26, 2008 by the European Space Agency shows the Mangala Fossae trough, a system of outflow channels on Mars, that bears evidence of lava deposition and catastrophic floods

A volcano on Mars half the size of France spewed so much lava 3.5 billion years ago that the weight displaced the Red Planet's outer layers, according to a study released Wednesday.

Mars' original north and south poles, in other words, are no longer where they once were.

The findings explain the unexpected location of dry river beds and underground reservoirs of water ice, as well as other Martian mysteries that have long perplexed scientists, the lead researcher told AFP.

"If a similar shift happened on Earth, Paris would be in the Polar Circle," said Sylvain Bouley, a geomorphologist at Universite Paris-Sud.

"We'd see Northern Lights in France, and wine grapes would be grown in Sudan."

The volcanic upheaval, which lasted a couple of hundred million years, tilted the surface of Mars 20 to 25 degrees, according to the study.

The lava flow created a plateau called the Tharsis dome more than 5,000 square kilometres (2,000 square miles) wide and 12 km (7.5 mi) thick on a planet half the diameter of Earth.

"The Tharsis dome is enormous, especially in relation to the size of Mars. It's an aberration," Bouley said.

This outcropping—upward of a billion billion tonnes in weight—was so huge it caused Mars' top two layers, the crust and the mantle, to swivel around, like the skin and flesh of a peach shifting in relation to its pit.

Already in 2010, a theoretical study showed that if the Tharsis dome were removed from Mars, the planet would shift on its axis.

It suddenly makes sense

Bouley and colleagues matched these computer models with simulations and observations—their own and those of other scientists.

Many things on Mars that begged explanation suddenly make sense in light of the new paradigm.

"Scientists couldn't figure out why the rivers"—dry riverbeds today—"were where they are. The positioning seemed arbitrary," Bouley told AFP.

"But if you take into account the shift in the surface, they all line up on the same tropical band."

Likewise the huge underground reservoirs of frozen water ice that should be closer to the poles. Once upon a time, we now know, they were.

The new theory also explains why the Tharsis dome is situated on the "new" equator, exactly where it would need to be for the planet to regain its equilibrium.

The findings, published in Nature, likewise challenge the standard chronology which assumes the Red Planet's rivers were formed after the Tharsis dome.

Most of these ancient waterways would have flowed from the cratered highlands of the Red Planet's southern hemisphere to the low plains of the north even without the massive lava fields, the study concluded.

"But there are still a lot of unanswered questions," cautioned Bouley.

"Did the tilt cause the magnetic fields to shut down? Did it contribute to the disappearance of Mars' atmosphere, or cause the rivers to stop flowing? These are things we don't know yet."

Explore further: Regional, not global, processes led to huge Martian floods

More information: Sylvain Bouley et al, Late Tharsis formation and implications for early Mars, Nature (2016). DOI: 10.1038/nature17171

Related Stories

Regional, not global, processes led to huge Martian floods

September 11, 2015

Gigantic groundwater outbursts created the largest flood channels in the solar system on Mars, 3.2 billion years ago. For many years it was thought that this was caused by the release of water from a global water table, but ...

Mars gullies likely contain 'no water', study says

December 21, 2015

Months after scientists announced "the strongest evidence yet" of liquid water on Mars, a study Monday said there was none at least in the valleys carved into numerous Red Planet slopes.

Farming water on Mars

October 5, 2015

Mars is a different place than Earth. There is water on Mars, more than the Moon, but lots less than on our own world. But the water on Mars is the same H2O we have here, and we should use it when we travel to Mars and set ...

Lava floods the ancient plains of Mars

March 7, 2014

Two distinct volcanic eruptions have flooded this area of Daedalia Planum with lava, flowing around an elevated fragment of ancient terrain.

Mars: What lies beneath

August 13, 2013

There is much more to Mars than meets the eye. By using the radar on Mars Express, we can see several kilometres below the surface to see what lies beneath.

Recommended for you

Dark matter may be smoother than expected

December 7, 2016

Analysis of a giant new galaxy survey, made with ESO's VLT Survey Telescope in Chile, suggests that dark matter may be less dense and more smoothly distributed throughout space than previously thought. An international team ...

Giant radio flare of Cygnus X-3 detected by astronomers

December 7, 2016

(Phys.org)—Russian astronomers have recently observed a giant radio flare from a strong X-ray binary source known as Cygnus X-3 (Cyg X-3 for short). The flare occurred after more than five years of quiescence of this source. ...

Saturn's bulging core implies moons younger than thought

December 7, 2016

Freshly harvested data from NASA's Cassini mission reveals that Saturn's bulging core and twisting gravitational forces offer clues to the ages of the planet's moons. Astronomers now believe that the ringed planet's moons ...

Cassini transmits first images from new orbit

December 7, 2016

NASA's Cassini spacecraft has sent to Earth its first views of Saturn's atmosphere since beginning the latest phase of its mission. The new images show scenes from high above Saturn's northern hemisphere, including the planet's ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

torbjorn_b_g_larsson
not rated yet Mar 03, 2016
The abstract (pay-walled paper) suggests surface water stability was contemporaneous with the Tharsis complex, but unless they see specific correlations this could relax the Tharsis-thick enough atmosphere link. The early habitability conditions keep being fuzzy. :-/

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.