Curiosity Discovers Unusual Pits on Mount Sharp During Sols 4988-4994

Michelle Minitti, the deputy lead investigator for the close-up camera, noted that these features were unlike anything previously observed during the mission. While ordinary pits are common on Mars, typically resulting from weathered rock and debris that form gaps filled with residual pebbles, these new depressions are larger and flatter. Their cause remains a mystery, as no clear sign of what created them has been identified.

To analyze this phenomenon, Curiosity employed multiple instruments, including the MAHLI and Mastcam for detailed imaging, while the ChemCam used lasers for remote photography. The resulting data revealed distinct material layers in the pits that do not correspond to the surrounding rock, offering an initial clue into this geological anomaly.

Mount Sharp, a five-kilometer-high sedimentary formation in the center of Gale Crater, documents the history of ancient lakes, rivers, and wind patterns. Curiosity has been methodically exploring these layers, examining variations in particle size, mineral composition, and coloration similar to how a geologist would study canyon walls on Earth. The pits appeared in an area known as Valle Grande, which also contains buttes named Cordillera, Tolhuaca, and Potosí. The presence of these features suggests previous changes in environmental conditions.

The scientific team is not considering the shapes as animal tracks, nor do they fit the characteristics of impact craters. Potential causes include wind erosion, fluids moving through the rock, or other weathering processes still unexplored by the rover. The lack of typical leftover debris complicates interpretations, with Minitti describing the bedrock as anything but mundane. She characterized the pits as an intriguing puzzle that highlights the ongoing scientific challenge of discerning their origins.