Multiple levels may suggest different episodes, but the common statistical age of the three levels shows that the last episode involved the whole crater. The origin of the lake water in Gale may have varied in time. According to the Amazonian age of Gale's floor, and the erosion direction in the crater, a flood from Elysium Basin is the most likely event to explain the material observed in Gale, and the formation of the last lake. Terrace spacing suggests a regular drop of the lake level in time. The presence of a lake of such volume during the Amazonian period is one more evidence that water was still active on Mars relatively recently.
Gale crater offers the rare opportunity to unveil a key-period of the martian history.
The Amazonian might proved not as cold and dry as previously thought. The sediments and rocks that were left of this period in Gale keep the record of the climatic conditions of the Amazonian and the clues that are missing to understand the climatic evolution of Mars. Diversified Geology - crustal mat. Trafficability TBD - Good at Viking Res.