Detecting unusual rocks on Mars

A duo of Mars probes have discovered a very ignimbrite igneous rock on Earth, revealing the planet's history of intense eruptions.

The Nili Fossae region of Mars, including the Jezero impact crater, which NASA's Perseverance rover is exploring, is rich in boulders filled with the volcanic mineral olivine. The same was found at Gusev crater, where NASA's Spirit rover operated until the end of its mission in 2010, according to new research published in the journal Icarus, led by Arizona State University. .

The olivine-rich rocks in the Gusev crater on Mars.

This is the first time scientists have confirmed the geological similarities between the two regions, suggesting they may have been formed by similar processes. The team then compared images taken by the Spirit spacecraft of Gusev crater rocks with images of rocks on Earth and also found a connection between them.

"It's an amazing discovery," said lead author Steve Ruff at Arizona State University. "I've seen the texture in the rock of Gusev crater very much like a specific volcanic rock found on our planet. It's ignimbrite igneous rock, made of ash, pumice and runoff. lava of violent eruptions".

Previously, no theory had suggested that ignimbrite was related to the olivine-rich rocks of Mars. If the new finding is correct, it means past eruptions on the red planet were more intense than scientists once thought.

"Imagine a cloud of hot gas hovering close to the ground, nearly molten ash and pumice flowing across the landscape for tens of miles, piling up in layers hundreds of feet thick at just a few feet. in a few days," Ruff describes.

To confirm the presence of ignimbrite igneous rock on Mars, scientists may have to wait until the Perseverance sampler returns to Earth to study it in the lab.