NASA's Perseverance rover found igneous rock rather than the expected sedimentary layers along the inner edge of Mars' Jezero Crater, and that rock preserves signs of interaction with water on at least three separate occasions, according to findings published Monday in Communications Earth & Environment. NASA's Jet Propulsion Laboratory reported the study on Sep 21, 2026.

The rover used its SuperCam instrument, which fires a laser up to 21 feet (6.5 meters) to analyze the chemistry of targets, to examine more than 185 bedrock targets across roughly 870 feet (265 meters) of elevation in the "Margin Unit." Higher-elevation rock rich in the mineral olivine shows almost no sign of water, while lower lakebed rock shows fractured olivine grains with silica between them. The team says the first water episode produced carbonate-filled fractures, a second may have been linked to the crater's ancient lake, and a later event created mineral veins containing calcium sulfate and fluorite at one eastern location.

Lead author Candice Bedford of Purdue University said the location became "a sort of crossroads for aqueous systems." The team can determine the sequence of water interactions but not their age. A key objective of Perseverance's mission is astrobiology, including the search for signs of ancient microbial life.