Exploratour - Water on Mars
Shoreline, or Not?
This picture shows how hard it is to prove something from a long distance away. When Viking visited Mars in 1979, it took pictures that suggested that there might be shorelines from an ancient beach. Twenty years later, Mars Global Suveyor has been able to take much better pictures.This image shows that what was thought to be an ancient shoreline really is not a shoreline at all. So some of the lakes which were thought to be the remains of floods are not lakes at all. This changes some of the proof for flooding on Mars.
The picture of the ancient "lake" formed by a flood was taken on the slopes of the Tharsis Ridge, as shown in the lower right-hand corner.