Dr. Brian Hynek of the University of Colorado and fellow geologists have mapped out the once great northern Martian ocean. The great northern ocean (no official name yet) was around 3.5 billion years ago! (For reference: the rocky planets are estimated being about 4.5 billion years old).
Another study by the group revealed the existence of 40,000 river valleys on Mars. The mapping of river valleys and deltas is useful in the exploration of whether or not there was life on Mars. Dr. Gaetano Di Achille stated that knowing where deltas were was useful because "[o]n Earth, deltas and lakes are excellent collectors and preservers of signs of past life. If life ever arose on Mars, deltas may be the key to unlocking Mars' biological past."
Good for these geologists to be applying their skills on the other planets. It is such a shame no physical geographers lent their skills to this or other related projects. We geographers are still stuck on the Earth.