Reading the spots in Cheyava Falls
Event image. WATSON photographed Cheyava Falls on 18 July 2024, sol 1212. Contrasting millimetre-scale spots occur between calcium-sulfate veins. Their distribution motivated chemical investigation; this photograph alone does not identify the origin of the patterns.
NASA/JPL image-use policy · credited mission imagery, resized to WebP
· Original image source · Image licenceA close investigation of patterns inside a rover’s sampling workspace.
- World
- Mars
- Case date or period
- 2024 observations · 2025 study
Look closer
Perseverance found contrasting spots and mineral veins in the Cheyava Falls rock. View the rock surface, the wider workspace and material retained in the drill, keeping their different scales in mind.
Follow the evidence
The patterns motivated detailed chemical study and sampling. A photograph shows where features occur, but cannot by itself determine the processes that produced them or establish past life.
The chemical case behind the spots
Hurowitz and colleagues’ 2025 Nature study combines imaging with rover spectroscopy rather than classifying spots by shape. It reports organic-bearing mudstones with small nodules and reaction fronts enriched in iron phosphate and iron sulfide, consistent with vivianite and greigite. Their distribution suggests chemical reactions after sediment deposition. Geological and mineral evidence favours a low-temperature setting. The authors call the combined findings potential biosignatures, a reason to investigate both biological and non-biological origins.
Why the alternatives remain open
The Nature authors explicitly consider abiotic iron reduction by organic compounds, including organics made without life or delivered from space. Producing the associated sulfide is harder to explain at low temperature; proposed hotter pathways lack supporting geological evidence here. That difficulty does not eliminate all non-biological possibilities. Laboratory and analogue work, and ultimately study of the Sapphire Canyon sample on Earth, could test competing mechanisms. Potential biosignature therefore remains an unresolved interpretation, not confirmed Martian life.
Sources & further reading
- Perseverance Finds a Rock With 'Leopard Spots' — NASA Image and Video Library / JPL
- Mastcam-Z Views the 'Cheyava Falls' Workspace — NASA Image and Video Library / JPL
- Mastcam-Z Views 'Leopard Spots' in Perseverance's Drill Bit — NASA Image and Video Library / JPL
- Redox-driven mineral and organic associations in Jezero Crater, Mars — Hurowitz and colleagues (2025) — Nature 645, 332–340 / Perseverance research team