Mysterious Boulder Found by NASA Rover on Mars Surface; What Does It Say About Red Planet's Geology?

While taking a shortcut to steer clear of a path full of boulders, NASA's Perseverance Mars rover discovered a field full of stones, the likes of which experts have never found before on the Red Planet.

A Rocky Terrain

On June 9, the Perseverance Mars rover reached its latest area of scientific interest after traversing through a dune field to avoid a field of boulders. This change of route shortened the estimated arrival time to the area named "Bright Angel" by several weeks. It also gave the scientists an opportunity to find exciting geologic features on the Red Planet.

The car-sized rover is in the later stages of its fourth science campaign where it aims to look for evidence of olivine deposits and carbonate in the "Margin Unit" which is found inside the Jezero Crater's rim. Located at the base of the northern channel wall, Bright Angel appears as a light-toned outcrop full of rocks.

These outcrops are believed to represent ancient rock exposed by river erosion or sediments that used to fill the channel. The research team hopes to find boulders that are different from those in the Margin Unit and collect more clues regarding the history of Jezero Crater.

In order to get to Bright Angel, Perseverance drove on a ridge along the Neretva Vallis rover channel, a region that looks like a barren desert. This dried-up river channel once carried a large amount of water into the Jezero Crater for billions of years.

According to Evan Graser, deputy strategic route planner lead at Jet Propulsion Laboratory, the team began paralleling the channel in late January and was making good progress. However, the boulders became bigger and more numerous, reducing the rover's average drive from a hundred meters per Martian day to only tens of meters.

Evan and colleagues decided to use rover imagery to pan drives of around 100 feet (30 meters) at a time. To go farther on any given Martian day, they rely on the rover's auto-navigation (AutoNav) system to take over the driving process.

As the boulders became more plentiful, however, AutoNav determined that the drive was not possible. This made it possible for the team to reach the target arrival at Bright Angel. They only hoped to find success cutting across 1,320-feet (400-meter) dune field in the river channel.

Never-Before-Seen Boulder

After traversing the inlet, it came upon a hill covered in boulders including some that have never before seen on Mars. One of them stands out as it appears as a pale, speckled boulder which is unlike any of the darker ones surrounding it.

This particular rock measures 18 inches (46 centimeters) wide and 14 inches (36 centimeters) tall. It was so distinct that scientists decided to give it a nickname. They call it "Atoko Point" in reference to the deeper geological mysteries of this barren and odd world.

Perseverance's SuperCam and Mastcam-Z analyzed the rock and discovered that it is made of minerals pyroxene and feldspar. Looking at the size, shape, and arrangement of its mineral grains and crystals, NASA has determined that Atoko Point is in a league of its own.

Some scientists assume that the minerals found on the rock were created in a subsurface body of magma which is currently exposed on the crater rim. Others also wonder if Atoko Point had been produced far beyond the walls of Jezero and was transported by Martian waters billions of years ago.