Img: Martian lake (impression). Credit: Gaetano Di Achille/University of Colorado

U.S. researchers have uncovered evidence of shorelines on Mars, a discovery that gathers further proof for the possibility of a watery past for the Red Planet, with ramifications for the possibility of the existence of previous life forms.

The shorelines point to the existence of a large lake up to 1,500 feet deep which may have covered as much as 80 square miles, according to lead researcher Gaetano Di Achille, Research Associate from the University of Colorado at Boulder.

"This is the first unambiguous evidence of shorelines on the surface of Mars," said Di Achille in a UC-Boulder news release. "The identification of the shorelines and accompanying geological evidence allows us to calculate the size and volume of the lake, which appears to have formed about 3.4 billion years ago."

The images of the site were taken from NASA's

"Finding shorelines is a Holy Grail of sorts to us," said CU-Boulder Assistant Professor Brian Hynek, who with Di Achille and CU-Boulder Research Associate Mindi Searls, wrote a paper for the journal Geophysical

Not only is the discovery important in the search for life that may have existed on Mars, it also is at odds with current theories of when water left the Red Planet.

"Not only does this research prove there was a long-lived lake system on Mars

Di Achille said the lake bed would be a great stop for landing future Mars missions.

"On Earth, deltas and lakes are excellent collectors and preservers of signs of past life," said Di Achille. "If life ever arose on Mars, deltas may be the key to unlocking Mars' biological past."