Outflow Channels May Make a Case for a Bygone Ocean on Mars.
Written by Linda M.V. Martel
Hawai'i Institute of Geophysics and Planetology
http://www.psrd.hawaii.edu/June01/MarsChryse.html
"High-resolution elevation data from the Mars Orbiter Laser Altimeter (MOLA) onboard the Mars Global Surveyor (MGS) spacecraft have been analyzed recently in Chryse Planitia to test the hypothesis that large outflow channels emptied into an ocean in this region of Mars. Researchers Mihail (Misha) Ivanov (Vernadsky Institute of Geochemistry and Analytical Chemistry) and James Head (Brown University) collected quantitative MOLA information on channel patterns, continuity, and elevations where those patterns change or disappear into the northern lowlands. Their recently published report describes how the channels end, or become more subtle, at elevations very close to a previously mapped geologic contact interpreted by some to represent a shoreline of an ancient ocean. Ivanov and Head hypothesize that the change in channel topography is consistent with flow of water from a river into a submarine environment with possible deposition of sediments by density currents deep into the North Polar basin."

This reports on research by Ivanov et.al. that outflow channels out of Chryse Planitia terminate at the locations of Contact 2, the more recent shoreline of the hypothesized ocean on Mars. They note this would be expected if they were emptying into an extensive ocean. Since there are lower elevations further north they argue there would be no reason for these widely separated flows to terminate at nearly the same elevation levels, unless there was a extensive body of water for these flows to empty into.

Bob Clark