NASA's Perseverance rover finds surprising volcanic rocks in ancient crater on Mars

Scientists have come across a surprising discovery of volcanic rocks on the floor of the Jezero crater which is believed to have once been filled with water. This 45-kilometre-wide crater on Mars is where NASA’s Perseverance rover landed on February 18, 2021, in search of evidence of microbial life as it once housed a massive lake, around 3.7 billion years ago. 

A study recently published in the journals Science and Science Advances revealed that the scientists were expecting to find sedimentary rocks but instead were surprised to discover two types of igneous rock. Sedimentary rocks are those which form when sand and mud settle in a once-watery environment, however, Perseverance's investigations found rocks that formed deep underground from magma, along with those that emerged from volcanic activity at the surface. 

Why is the discovery significant?

Scientists are happy with this discovery because igneous rocks are considered excellent timekeepers since their crystals can reveal the exact time those rocks formed. "This will address some major questions: When was Mars’ climate conducive to lakes and rivers on the planet’s surface, and when did it change to the very cold and dry conditions we see today?" Ken Farley of Caltech, Perseverance’s project scientist and study author said, as per NASA's report. 

The experts, however, underscored that igneous rocks do not have the potential of preserving signs of ancient Martian life. In contrast, it is not easy to determine the age of sedimentary rocks because they result from the deposition of different rocks but are better at preserving life signs. 

Using near-infrared data gathered by Perseverance's SuperCam, scientists have confirmed that water altered minerals in the crater floor rocks. "SuperCam’s data suggests that either these rock layers were isolated from Jezero’s lake water or that the lake existed for a limited duration,” said Roger Wiens, SuperCam’s principal investigator at Purdue University said in a statement. Currently, the experts are excited about carrying out investigations after the new discovery. Besides, the rover has collected a dozen of rock samples which would be sent back early next decade for investigations using much more sophisticated instruments.