'Salt deposits' on Mars point towards planet's last habitable surface water

In a new research, scientists have stumbled upon salt deposits on Mars, pointing towards what could have been the last habitable surface water on the Red Plant before it went cold and dry.

Researchers at the University of Colorado Boulder have discovered evidence of an ancient lake that likely represents some of the last potentially habitable surface water ever to exist on the Mars.

The study examined an 18-square-mile chloride salt deposit in the planet's Meridiani region near the Mars Opportunity rover's landing site.

Digital terrain mapping and mineralogical analysis of the features surrounding the deposit indicate that this one-time lakebed is no older than 3.6 billion years old, well after the time period when Mars is thought to have been warm enough to sustain large amounts of surface water planet-wide.

Planetary scientists believe that the solar system formed approximately 4.6 billion years ago.

Lead author Brian Hynek said that it was a long-lived lake, and they were able to put a very good time boundary on its maximum age, adding that they can be pretty certain that this is one of the last instances of a sizeable lake on Mars.

The researchers estimated that the lake was only about eight percent as salty as the Earth's oceans and therefore may have been hospitable to microbial life.

Hynek said that by salinity alone, it certainly seems as though this lake would have been habitable throughout much of its existence.

The study is published in the journal Geology.