MARS WATER HIT THE ROCKS THREE TIMES! | Perseverance finds Jezero’s Margin Unit wasn’t a simple lakebed — igneous rock altered by lakes, groundwater, then hydrothermal fluids

NASA’s Perseverance rover reached Jezero Crater’s “Margin Unit” expecting sedimentary rock from an ancient lakebed — and got a surprise instead: igneous rock that records water interacting with volcanic material on at least three separate occasions, NASA/JPL reported Sept. 21, 2026.

The first water events altered olivine into carbonate-filled fractures. A later pulse cut ~10-inch (25 cm) mineral veins packed with calcium sulfate and fluorite — a signature of hot hydrothermal fluids moving through volcanic rock, not a quiet shoreline.

The findings, published in Communications Earth & Environment, rewrite the simple lakebed story for this part of Jezero. “Mars constantly throws surprises,” is the vibe from the science team (Bedford and colleagues) as Perseverance keeps proving the crater’s water history was messy, multi-stage, and geochemically rich.

Sources: NASA/JPL; NASA