Mars researchers say the discovery of a gully system, even an isolated one, that supported running water as recently as 1.25 million years ago greatly extends the time that liquid water could have been active on the Red Planet.
It also adds to evidence that Mars experienced a recent ice age in which polar ice is thought to have been transported toward the planet's equator, where it settled in mid-latitude deposits.
A study of images from Nasa's Mars Reconaissance Orbiter (MRO) shows there were four intervals in which water-borne sediments were carried down the steep slopes of nearby features called alcoves and laid down in a deposit called an alluvial fan.
The team considered other possibilities, such as groundwater bubbling up to the surface, but said the most likely mode of formation for the gullies was the melting of snow and ice deposits that created "modest" flows of water.
No comments:
Post a Comment