Is the largest volcano in our solar system an island after all?

French researchers believe that the largest volcano in our solar system was surrounded by masses of water. Why is this important?

Located on Mars at an altitude of 21.9 km, Olympus Mons is the highest volcano in our solar system. Its base diameter is about 600 km. Scientists from the University of Paris-Saclay have analyzed the slopes of Olympus Mons and the Tharsis region of Mars, and are convinced that the volcano was once an island in a vast ocean.

Anthony Hildenbrand’s research group found that the supervolcano has morphological similarities to active volcanic islands on Earth (such as Hawaii). What scientists are particularly interested in are the cliffs at the edge of the volcano’s base. It extends to a height of up to six kilometers and merges into a pebble-like landscape.

Some researchers believe that there are slopes on this cliff that were formed due to the enormous load of the Mountain of Fire, while others interpret them as erosion. But Hildenbrand and his colleagues believe that Olympus Mons poured its lava into the ocean.

“We believe that the upper edge of the six-kilometre-high cliff was created by lava flowing into liquid water,” they wrote in the journal Earth and Planetary Science Letters. The interaction of glowing lava with cold seawater creates similar, though much smaller, lava slopes on terrestrial volcanic islands such as Hawaii, the Galapagos, or Reunion.

When liquid rock collides with water, it suddenly cools and solidifies. In the journal, scientists talk about “strong discrepancies in viscosity.” The lava became sticky and solid more quickly in these places. As a result, high cliffs piled up on the former beach.

But there is also criticism of the study by the Paris researchers. Gerald Eichstadt, who works for NASA as a citizen scientist. He criticizes incomplete arguments and choice of images.

Eichstädt: “If there is direct contact between lava and water, shouldn’t there be almost unmistakable traces of lava, as is the case in Hawaii? I wonder why the argument relies only on the somewhat ambiguous cutting edge and not with references to a lava pillow “Volcanism in widely available high-resolution satellite images.”

Olympus Mons formed about three billion years ago at a time when, according to knowledge, there was still water on Mars – and perhaps life, too. Researchers in Paris believe they have found a good target for a Mars mission with a volcanic shelf.

They suggest that “the coastlines we hypothesize can be dated using radiometric methods.” “It could also be a clear witness to past sea levels, where one can specifically look for traces of early life.”