NASA's Mars Opportunity Rover has taken some break from its other investigative activities to closely examine some oddly shaped rocks it has never seen on the surface of the Red Planet before.

Opportunity found the outcrops while climbing an overlook to survey the "Marathon Valley," the current location of the mission chosen as a destination to conduct scientific investigations based on spectrometer observations from orbit suggesting exposures of clay minerals, which scientists believe to be indication of ancient presence of Martian water.

The rover team found that the rocks are so different from those they have earlier examined on Mars that they decided to halt other activities in order to conduct a thorough investigation of the rocks.

"We drove to the edge of a plateau to look down in the valley, and we found these big, dark-gray blocks along the ridgeline," said Opportunity Project Scientist Matt Golombek. "We checked one and found its composition is different from any ever measured before on Mars. So, whoa! Let's study these more before moving on."

Analysis using the Alpha Particle X-ray Spectrometer instrument found at the end of the rover's robotic arm shows that the first rock at the site called the "Jean-Baptiste Charbonneau," has a relatively high concentration of silicon and aluminum. Its overall composition has neither been observed by either the Opportunity or Spirit before.

Spirit was another Mars robotic rover that was active between the years 2004 and 2010. Both the Opportunity and its twin rover's missions are to study the surface of Mars as part of the Mars Exploration Program of NASA. The two missions are specifically launched to discover the history of water on the Red Planet.

The second target rock at the site is dubbed "Sergeant Charles Floyd" to keep up with the Lewis and Clark naming theme.

The rocks are gray but the visible light spectrum of the Floyd type has more blue compared with most rocks on the Martian surface. The spectrum of the Charbonneau type, on the other hand, has more purple. The bluer rocks are also more likely to lie higher on the ridge.

The team behind Opportunity has already uploaded the new version of the rover's flight software, which is designed to use only six of its seven flash memory banks since the seventh has some issues. Although Opportunity is using the new software, a memory reformatting is still required before the rover could resume using its flash memory.