Hundreds of massive spiral patterns have been spotted on the surface of Mars, indicating that Mars may have been volcanically active within the past 20 million years, the Associated Press reported.
The coils, which bear a resemblance to Hawaiian lava flows, are located in the Athabasca Valles, a maze of valleys near the Mars equator, the AP reported. Scientists have long debated whether this region was shaped by ice or volcanic lava flows.
An eagle-eyed graduate student at the University of Arizona, Andrew Ryan, noticed the spirals last year, when analyzing high-resolution pictures taken by the Mars Reconnaissance Orbiter for a class project, the AP reported.
Ryan counted 269 coils up to 100 feet wide, National Geographic News reported.
"Everything that we have observed in Athabasca Valles can be formed by lava. Although you could attribute certain features to ice, the lava coils indicate that this is not the case," Ryan told National Geographic News.
"There are no known mechanisms to naturally produce spiral patterns in ice-rich environments on the scale and frequency observed in our study area," Ryan and co-author Philip Christensen wrote in a paper about the spirals in this week's issue of the journal Science, according to National Geographic News.
Planetary scientist David Paige of the University of California, Los Angeles, told the AP that the discovery "illustrates just how complicated Mars' geologic history appears to really be.”
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