Perseverance keeps finding purple on Mars, despite the fact that red is the most commonly identified hue with the, well, Red Planet, Purple-hued rocks, to be precise. In addition, they are all over the place. The intrepid Mars rover has discovered purple rocks at practically every site it’s visited in Jezero Crater so far, ranging in size from massive rocks to small pebbles, but NASA scientists aren’t sure what they are or how they developed.
Geochemist Ann Ollila, who presented an early investigation of the strange purple covering at the recent American Geophysical Union (AGU) meeting, told National Geographic, “I don’t really have a good answer for you.” On some rocks, the purple appears as a thin, smooth covering and on others as paint-like splodges. Deciphering its chemical composition could reveal information about Mars’s old environment.
This is not the first time purple rocks — or even green rocks — have discovered on the Red Planet. In 2016, curiosity uncovered several around the base of Mount Sharp. Curiosity’s Chemical and Mineralogy (CheMin) instrument had detected hematite, an iron oxide crystal, and the purple-hued pebbles discovered where Curiosity’s Chemical and Mineralogy (CheMin) instrument had detected hematite, an iron oxide crystal. It also helped that the winds and windblown sand in the area where Curiosity was exploring kept the rocks dust-free, which would have obscured the color of the rocks otherwise.
According to another early analysis presented at the AGU conference, the purple patches spotted by Perseverance have also found in less dusty areas, according to a team led by Bradley Garczynski of Purdue University who are studying the coatings using images captured by Perseverance’s “eye” cams, the Mastcam-Z cameras. Their findings show that they may possibly include different forms of iron oxide. We have not encountered this type of purple rock covering before, according to Garczynski, and especially not in the regularity that Perseverance appears to be encountering it.
To analyze the coating, Ollila’s team used Perseverances’ Supercam, which can blast a laser at rocks to melt them and study their properties. The purple layer appears to be softer and chemically unique from the rock layer below, as well as possibly high in hydrogen and magnesium, according to their first findings. The presence of hydrogen and iron oxide in the purple patches suggests that water played a part in their formation.
Perseverance has been studying the Jezero Crater, a meteorite impact crater that previously held an ancient lake, and there is plenty of evidence that Mars was once a wet planet. However, Percy’s path, which has led him to these purple rocks, does not truly follow lake deposits but rather rocks created by cooling magma.
Therefore, it still a mystery how these purple-hued boulders got to their current location, and how or when they were exposed to water. Scientists have been investigating whether rock coatings discovered on Mars could help preserve traces of ancient microbial life by preventing organic material from being degraded by the Sun’s powerful radiation. As a result, this new riddle could aid in the search for an answer to the age-old question of whether or not there was or could be life on Mars.