Overview
- Researchers reporting in Nature on Wednesday identified a wide, gently sloping band in Mars’s northern lowlands that they interpret as a coastal shelf.
- The team used curvature and slope measurements from NASA’s Mars Global Surveyor topography to trace a continuous zone that resembles the shallow seafloor bordering Earth’s continents.
- Within this band they mapped signs of coastal processes, including deltas, shoreline deposits, and river-built sediments that together point to long-lived water activity.
- The feature, likened to a planet-scale bathtub ring, suggests an ocean that persisted for millions of years around 3.7 billion years ago and could guide rover searches for layered rocks, clinoforms, and wave-made textures.
- Authors note the surface has been reshaped by volcanoes and wind over billions of years, so in‑person sampling is needed, though the finding aligns with earlier reports of deformed shorelines, mapped deltas, and Zhurong rover radar hints of buried beaches.