Perseverance maps a sequence of Martian water events, not their dates
SuperCam measurements reveal successive changes to Jezero's rocks, while the timing of water episodes remains unresolved.
NASA's Perseverance rover has traced at least three episodes of water altering rocks in Jezero Crater's Margin Unit, but the sequence is clearer than the dates. A September 21 JPL report says the team cannot yet determine when those encounters occurred.
The evidence comes from SuperCam, which reads mineral signals and can fire its laser at targets up to 6.5 metres away. Light from the resulting plasma reveals the target's chemical composition. The rover examined more than 185 separate bedrock targets across the unit.
Researchers interpret carbonate-filled fractures as the result of groundwater reacting with olivine. A later episode may have involved the crater's lake. Mineral veins containing fluorite point to a subsequent hot-water event.
The distinction matters: an instrument records chemistry, while scientists reconstruct the processes that could explain it. These observations refine a water history; they neither date each episode nor establish that organisms inhabited the rocks.
프리즘코리아 편집국 > Alex Rowan
