An unusual type of rock detected by two Mars rovers may indicate that the Martian landscape was shaped by extremely violent volcanic eruptions.
The Nili Fossae region of Marswhich includes the Jezero Crater that NASA perseverance vehicle is currently exploring, is full of bedrock laden with the volcanic mineral olivine. That same olivine-rich bedrock was also found in Gusev Crater, where NASA spirit rover it wandered until its disappearance in 2010. But the connection between the regions was not made until now, by a team led by planetary geologist Steve Ruff of Arizona State University. The researchers examined data from several Mars rovers to confirm geological similarities, indicating that local rocks could have been formed by similar processes. Scientists then compared Spirit’s images of the rock from Gusev Crater with images of rocks from Earth.
“That was a eureka moment,” Ruff said in a tone statement. “I was seeing the same kind of textures in the Gusev Crater rocks as a very specific type of volcanic rock found here on Earth.”
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That rock is ignimbrite, which is created from the ash, pumice, and pyroclastic flows of powerful volcanic eruptions. “No one had previously suggested ignimbrites as an explanation for olivine-rich bedrock on Mars,” Ruff said. “And it’s possible that this is the type of rock that the Perseverance rover has been driving over and sampling for the past year.”
Although researchers have long theorized that volcanism was responsible for producing Nili Fossae (olivine is, after all, a volcanic mineral), the identification of ignimbrite, if proven accurate, would indicate that the eruptions were more catastrophic than previously thought.
“Imagine a cloud of hot gases and nearly molten ash and pumice clinging to the ground and streaming across the landscape for dozens of miles and building up in layers up to hundreds of feet thick in just a few days,” Ruff said. about the eruptions that have produced this type of rock in land.
To confirm the presence of ignimbrite on Mars, scientists say they will have to study the rocks in a laboratory on Earth, another argument for the planned Mars Sample Return mission to transport Perseverance samples back to Earth.
The results of this study will be published in a paper in Icarus magazine in July.