Washington: A geologist at the University at Buffalo has suggested that one of the supposedly best understood and least interesting landscapes on Mars is hiding something that could rewrite the planet’s history.
Tracy Gregg found that decades of assumptions regarding the wide, flat Hesperia Planum are not holding up very well under renewed scrutiny with higher-resolution, more recent spacecraft data.
After early Mars scientists decided Hesperia Planum looked like a lava-filled plain, no one really revisited the matter and the place was used to exemplify something rather important: The base of a major transitional period in the geologic time scale of Mars, she stated.
But when Gregg and her student Carolyn Roberts started looking at this classic Martian lava plain with modern data sets, they ran into trouble.
“There’s a volcano in Hesperia Planum that not many people pay attention to because it’s very small,” Gregg said.
“As I started looking closer at the broader region — I can’t find any other volcanic vents, any flows. I just kept looking for evidence of lava flows. It’s kind of frustrating. There is nothing like that in the Hesperia Planum.
“A likely cause of this trouble is the thick dust that blankets Hesperia Planum. It covers everywhere like a snowfall,” she said.
She discovered a dozen narrow, sinuous channels, called rilles, just a few hundred meters wide and up to hundreds of kilometres long.
These rilles have no obvious sources or destinations and it is not at all clear they are volcanic.
"The question I have is what made the channels. Was it water, lava, or something else?” noted Gregg.
To begin to sort the matter out, Gregg and Roberts are now looking for help on the Moon.
Gregg is not worried that Mars history will need to be rewritten, but she does suspect that Hesperia Planum is a lot more complicated than people has long thought.
Their preliminary findings were presented at the meeting of The Geological Society of America in Minneapolis.