How did the ancient Martian *environment* differ from its observed coastal *geomorphology*?

The environment was cold with a thin atmosphere, despite beach geomorphology

There is a critical distinction drawn between the physical shape of the land (geomorphology) and the surrounding conditions (environment). The geomorphology—the presence of beaches, ripples, and layered sediments—clearly indicates that liquid water existed long enough to be shaped by wave action. However, the environmental context inferred from the planet's overall state suggests that ancient Mars was substantially colder and possessed a very thin atmosphere compared to modern Earth. This thin atmosphere meant that any exposed water would rapidly evaporate or freeze, and the surface lacked a strong shield against space radiation, making the environment extremely inhospitable despite the presence of wave-sculpted coasts.