Massive Unseen Structures Found Beneath Mars' Surface

Mars has always sparked curiosity, but a discovery beneath its surface has thrown planetary scientists for a loop. Researchers have uncovered massive, dense structures buried deep within the Red Planet, and no one is entirely sure what they are or what they could mean for Mars' past, present, and future.

The most striking of these anomalies lies beneath Tharsis Montes, the vast volcanic plateau that is home to Olympus Mons, the tallest volcano in the entire solar system. According to a study published in JGR: Planets, the underground mass spans about 1,750 kilometers (just over 1,000 miles) across and sits at a depth of 1,100 kilometers (684 miles). That is enormous by any standard.

Scientists are particularly intrigued by the possibility that this mass might be a mantle plume, a giant column of hot material rising from deep inside the planet. On Earth, mantle plumes fuel volcanic hotspots like those in Hawaii. If Mars has something similar occurring, it could mean the planet is not as geologically dead as we once thought.

“There seems to be a big mass (something light) deep in Mars’ layer, possibly rising from the mantle,” the authors wrote in the study. “It shows that Mars might still have active movements happening inside it, creating new volcanic features on the surface.”

Curiously, there’s no trace of those deep structures on the overlying surface, which implies that impactors didn’t form them.

That’s a significant finding. Until now, Mars has primarily been considered a dormant planet, with its volcanic activity long gone. But this new evidence suggests that something could still be bubbling beneath the crust, especially in the Tharsis region, which geologically resurfaced not so long ago (in planetary terms, at least), possibly within the last few tens of millions of years.

The team behind the research, led by Bart Root from Delft University of Technology, believes the structure is slowly pushing its way upward.

“A plume head is currently flowing upward towards the lithosphere to generate active volcanism in the geological future,” they explain.Root et al.

If this plume reaches the surface, it could eventually trigger new volcanic eruptions on Mars. And that’s not just speculation; the fact that Tharsis Montes is significantly more elevated than the surrounding regions hints that something deep underground is physically pushing it up.

This directly contradicts a long-standing idea in planetary geology known as flexural isostasy, which suggests that the weight of such prominent features should cause the crust to bend and sink, not rise.

“This means we need to rethink how we understand the support for the big volcano and its surroundings,” the researchers note.

And Tharsis isn’t the only place where strange phenomena are occurring beneath the Martian crust. The study also points to gravitational anomalies under Mars’ northern polar plains.

These dense features are buried beneath what is believed to be sediment from an ancient ocean floor and are about 300 to 400 kg/m³ denser than the surrounding materials.

Geological Implications

Dr. Robert P. McMillan, a planetary geologist at the Mars Geology Institute, highlights the significance of these dense structures found beneath Mars' surface. He suggests that they could represent ancient volcanic activity or even massive tectonic shifts. Understanding these geological formations helps scientists reconstruct the planet's climatic history, which ultimately informs us about the potential for past life.

By employing advanced seismic imaging techniques, researchers can further unravel the mysteries of these hidden formations. McMillan emphasizes that applying interdisciplinary approaches, such as combining geology with astrobiology, will expand our knowledge of Mars significantly.

Colourised Mars: Tharsis Montes trio with Olympus Mons to the northwest.

Similar gravitational anomalies have been linked to huge impact basins on Earth's Moon. The theory is that the asteroids or comets that created those basins were made of denser material than the Moon, and their remnants now sit below the surface. However, no trace of impact features above these new anomalies is visible on Mars.

“These dense structures could be volcanic in origin or could be compacted material due to ancient impacts,” said Dr. Root. Interestingly, one of the 20 features they identified even “resembles the shape of a dog.”“There seems to be no trace of them at the surface,” he continued. “However, through gravity data, we have a tantalizing glimpse into the older history of the northern hemisphere of Mars.”Arizona State University

Still, even with these exciting clues, researchers say they are only scratching the surface. They'll need better data to understand what’s going on down there; for that, they’re hoping to launch a new mission.

The proposed project is called Martian Quantum Gravity, or MaQuIs. It would use the same advanced gravitational mapping technology already employed on missions to study the Moon and Earth to get a clearer picture of what lies beneath Mars’ surface.

“Observations with MaQuIs would enable us to better explore the subsurface of Mars,” said Dr. Lisa Wörner of the German Aerospace Center (DLR), speaking at the Europlanet Science Congress 2024. “This would help us find out more about these mysterious hidden features and study ongoing mantle convection, as well as understand dynamic surface processes like atmospheric seasonal changes and the detection of groundwater reservoirs.”

So, what does all this mean for Mars? It’s still too early to say for sure. But if the planet has an active mantle plume, or several, it could change everything we thought we knew about its geology, history, and future.

One thing is clear: Mars still has secrets, and we’re just beginning to uncover them.

Dr. Linda Green, a geophysicist at NASA, points out the importance of collaboration in planetary studies. She advises that combining data from various missions, such as the Mars Reconnaissance Orbiter and the InSight lander, will yield a more comprehensive understanding of Martian geology.

Green emphasizes that sharing findings and methodologies among scientists can lead to innovative solutions for interpreting complex data sets. She advocates for open-access databases that encourage collaboration, allowing researchers worldwide to contribute to this exciting field of study.

Understanding the Deeper Patterns

The discovery of massive, unseen structures beneath Mars' surface marks a pivotal moment in planetary science. Experts like Dr. McMillan and Dr. Green encourage interdisciplinary collaboration and innovative research methods to unlock the secrets of these geological formations. By integrating insights from various scientific domains, we can develop a clearer picture of Mars' geological history and its implications for the potential existence of life.

As we continue to explore, it's crucial that researchers maintain open communication and share their findings, paving the way for future discoveries that could reshape our understanding of not just Mars, but planetary geology as a whole.