Massive volcano “hiding in plain sight” on Mars

A giant volcano has been ‘hiding’  on the surface of Mars – but scientists have only just identified the behemoth, as well as possible glacier ice beneath its surface.

The volcano has been provisionally given the title “Noctis volcano” pending an official name.

Noctis volcano has been imaged repeatedly since 1971. But it has been eroded almost beyond recognition. It lies at the border between the Noctis Labyrinthus – a region of maze-like, deep, steep-walled valleys – and the vast canyons of Valles Marineris.

Diagram of mars valleys and volcanoes on black background
The newly discovered giant volcano on Mars is located just south of the planet’s equator. Credit: Background image: NASA/USGS Mars globe. Geologic interpretation and annotations by Pascal Lee and Sourabh Shubham 2024.

The newly discovered volcano lies on the eastern part of Mars’s Tharsis volcanic province.

Its true nature as a volcano was finally given away when planetary scientists were analysing the remains of a glacier in 2023, they announced at the 55th Lunar and Planetary Science Conference held in The Woodlands, Texas.

A paper has been published on the Universities Space Research Association website.

Noctis volcano is 9,022 metres high and 450 km wide making it nearly 200 metres taller than Mt Everest. But it’s not the Red Planet’s biggest volcano.

Mars boasts the tallest mountain and largest volcano in the solar system. Olympus Mons in the western Tharsis is 21.9 km above datum (zero elevation on Mars, like “sea level” on Earth), rising 26 km above the low-lying plains out of which it rises. This “shield volcano” – so named because of its shape – covers an area of about 300,000 square kilometres – roughly the size of Italy, or the size of the Australian states of Victoria and Tasmania combined.

While Noctis volcano is a relative minnow, it may prove to be geologically significant.

It’s discovery sheds light on why this region of Mars has such a wide variety of minerals. “In some sense, this large volcano is a long-sought ‘smoking gun,’” says co-author Sourabh Shubham, a graduate student at University of Maryland, US.

The analysis also describes a 5,000-square-kilomitre area of volcanic deposits. Among these are many “blister-like” mounds. The researchers believe these to be “rootless cones” produced by steam vented when a thin blanket of hot volcanic material rests on top of water or ice.

It lends further credence to the idea that there is a glacier underneath the surface in the region.

The site presents a new location to study Mars’s geological evolution, as well as expand the search for life and plan for future missions to the Red Planet.

Topographic map of features on mars surface
Topographic map of the Noctis volcano. Credit: Background images: NASA Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) mosaic and Mars Global Surveyor (MGS) Mars Orbiter Laser Altimeter (MOLA) digital elevation model. Geologic interpretation & annotations by Pascal Lee & Sourabh Shubham 2024.

“It’s really a combination of things that makes the Noctis volcano site exceptionally exciting,” says Dr Pascal Lee, a planetary scientist with the SETI Institute and Mars Institute.

“It’s an ancient and long-lived volcano so deeply eroded that you could hike, drive, or fly through it to examine, sample, and date different parts of its interior to study Mars’ evolution through time. It has also had a long history of heat interacting with water and ice, which makes it a prime location for astrobiology and our search for signs of life.

“Finally, with glacier ice likely still preserved near the surface in a relatively warm equatorial region on Mars, the place is looking very attractive for robotic and human exploration,” Lee adds.

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