They think Jezero used to be filled with a lake.
' (/ˈjɛzəroʊ/) is a crater on Mars located at 18.38°N 77.58°E in the Syrtis Major quadrangle. The diameter of the crater is about 49.0 km (30.4 mi). Thought to have once been flooded with water, the crater contains a fan-delta deposit rich in clays. The lake in the crater was present when valley networks were forming on Mars. Besides having a delta, the crater shows point bars and inverted channels. From a study of the delta and channels, it was concluded that the lake ins