As we reported recently, NASA scientists recently discovered something amazing about the Red Planet thanks to a treasure trove of data from the Mars Curiosity rover, and that is that an ancient lake may have had the perfect conditions to host multiple types of microbes. But more details have emerged that suggest that this find is even bigger when it comes to the search for alien life.

Now, scientists think that the 3 billion year old lake at the Gale Crater, which the Curiosity rover is presently exploring, may have existed for a staggering 700 million years, and it was warm for much of that time. That certainly would have been long enough for some form of life to develop.

And even after the lake dried up and filled with sand, scientists, found, groundwater would still have been trickling through the area. The findings are based on three and a half years worth of analyses of rock samples by Curiosity, and its instruments were used to examine their chemical compositions.

“We’re learning that in parts of the lake and at certain times, the water carried more oxygen,” said Roger Wiens, a planetary scientist at Los Alamos National Laboratory and co-author of the study, published today in the journal Science. “This matters because it affects what minerals are deposited in the sediments, and also because oxygen is important for life. But we have to remember that at the time of Gale Lake, life on our planet had not yet adapted to using oxygen–photosynthesis had not yet been invented. Instead, the oxidation state of certain elements like manganese or iron may have been more important for life, if it ever existed on Mars. These oxidation states would be controlled by the dissolved oxygen content of the water.”