...NASA announced this morning, showing pictures taken by the Mars Global Surveyor before it fell silent in November.
Actually, I've been waiting for this announcement a couple of days now, and I am a bit disappointed. Evidence (also uncovered by the Global Surveyor) for recent water flows on the Red Planet is a couple of years old. Thus far it has mostly been in the form of gullies in crater walls which appear to have been formed by a liquid cascade of some kind. However, the new pictures also:
...[document] the formation of new craters on the plant's surface and [show] bright, light-coloured deposits in gullies that were not present in previous photos.
They concluded the deposits - possibly mud, salt or frost - were left there when water recently cascaded through the channels.
I think it is one of these deposits visible in the picture top left.