Martian Rover Spirit Finds a Scientific ‘Pot of Gold’

A mysterious rock found by NASA’s Spirit rover at the foot of Mars’ Columbia Hills continues to puzzle scientists, while the Opportunity rover is discovering that there was more water at Meridiani Planum than originally suspected.

The mystifying rock discovered by Spirit is like nothing scientists have seen before, on Mars or on Earth, said principal scientist Steven Squyres of Cornell University. “We may be dealing with something uniquely Martian here,” he said.

The rock, called Pot of Gold, is about the size of a softball. Its most intriguing features are tiny stalks with “little nuggets” on the end of each, “kind of dangling out there,” Squyres said. The stalks point in all directions and the nuggets are not close to round.

“I don’t know how these things formed, and they are driving me nuts, to be perfectly honest,” Squyres said. The team has been using the instruments on the rover to examine the rock’s chemical makeup, but the small size of the rock, and particularly of the nuggets, is impeding the scientists’ progress.

What the instruments have shown so far is that Pot of Gold contains hematite, an iron-bearing mineral that is often, but not always, formed in the presence of water. This is the first evidence of the mineral at Gusev Crater. A substantial quantity of hematite was found by the Opportunity rover in Meridiani Planum on the other side of Mars.

Opportunity, meanwhile, has proceeded about 5 yards into Endurance Crater and is now parked on the edge of a steeper incline, which descends at an angle of about 40 degrees.

As the craft proceeds into the crater, Squyres said, “we are seeing an awful lot of salt down there, considerably more than we initially expected.” The sulfate salts Opportunity is finding were produced in water, and the more salt there is now, the more water there must once have been on the surface.

Spirit landed on Mars on Jan. 3, Opportunity on Jan. 24.