QUESTION:
About how far did the rocks travel when they were moved by these giant
floods?

ANSWER from Wendy Calvin on August 4, 1997:
Well, if the rocks came from the very start of the Ares Vallis outflow
channel they could have traveled 1000km (600 miles)!  Floods of similar size
are suggested to have occured on Earth at the end of the last ice age, about
15,000 years ago.  At that time an ice dam on a giant lake in Idaho/Montana
broke and floods washed from the Pend Oreille Lake in Idaho across
Washington state to the Columbia River valley and out into the pacific
ocean.