Overview
- A PNAS study delivers the first planet-wide inventory of major Martian river systems, identifying 16 large drainage basins linked to long-lived surface water.
- Researchers combined previously mapped valley networks, lakes, rivers, canyons and sediment deposits to outline 19 clusters, 16 of which form watersheds of at least 100,000 square kilometers.
- The large basins occupy about 5% of Mars' ancient surface yet account for roughly 42% of the total material eroded by rivers, indicating disproportionately high sediment transport.
- The mapped watersheds are prioritized as search areas for past life because long flow paths enhance water–rock interaction, though the ultimate sediment sinks and in-situ confirmation remain to be determined.
- Mars hosts far fewer large basins than Earth’s 91, likely influenced by its lack of plate tectonics, and independent coverage reports these systems comprise about 49% of outlet‑canyon length.