http://www.digitaljournal.com/science/mars-once-had-a-massive-lake-nasa-reports/article/419793

Mars once had a massive lake, NASA reports

Posted Dec 9, 2014 by Micki Hogan
According to reports released by NASA, Mars' Gale Crater once contained a massive lake. NASA presented evidence that also suggests the lake existed for millions of years, long enough to sustain life.
The selfie taken by the Curiosity rover
The selfie taken by the Curiosity rover
Via NASA
Since the Mars Curiosity Rover landed in the Gale Crater in 2012 on Mars, the rover has been studying it. The report says that rivers probably flowed from Mars' Mount Sharp. The rivers flowed into the Gale Crater and the water also carried debris, like sand and other particles, into the mouth of the river. The debris settled once it reached the lake and the layers of sediment grew over the years.
This is similar to Earth's layers of sediment. The Rover has been studying the sediment and can now determine that a lake existed in the crater for millions of years. It is possible that life on Mars could have evolved within the lake.
The great thing about a lake that occurs repeatedly, over and over, is that each time it comes back it is another experiment to tell you how the environment works, John Grotzinger, project coordinator told the LA Times:
As Curiosity climbs higher on Mount Sharp, we will have a series of experiments to show patterns in how the atmosphere and the water and the sediments interact. We may see how the chemistry changed in the lakes over time. This is a hypothesis supported by what we have observed so far, providing a framework for testing in the coming year.
Since 2012 the Curiosity Rover has made the journey to the base of Mount Sharp, approximately 5 miles. The reason to study Mount Sharp is because the sediment there is taller than most points in the crater and tells a history dating further back than most areas of the crater.
Curiosity science team member Sanjeev Gupta further explained:
We found sedimentary rocks suggestive of small, ancient deltas stacked on top of one another. Curiosity crossed a boundary from an environment dominated by rivers to an environment dominated by lakes.
As reported to the website RT the study is helping compare Earth's evolution compared to the evolution of Mars. It is also one step closer to conclusively confirming life on Mars.
Mars - The Rocky Planets | FindTheBest