No. 16: Summer 1981
Long, sinuous depressions called "outflow channels" are concentrated in the equatorial regions of Mars. They clearly resemble terrestrial stream beds and have been attributed to water action. The ancient Spokane Flood that carved our Washington State's channeled scablands is seen as an apt terrestrial analogy. The Martian channels, however, are much larger than the water-eroded terrestrial analogs. The authors of the subject paper suggest that ice rather than water created the Martian channels, pointing out that terrestrial ice-stream and glacier landforms are much closer to the Martian features in terms of scale.
(Lucchitta, Baerbel K., et al; "Did Ice Streams Carve Martian Outflow Channels?" Nature, 290:759, 1981.)
Comment. This suggests the possibility that earth and Mars may have had synchronous Ice Ages due to solar variations or, perhaps, the envelopment of the entire solar system by a huge cloud of absorbing matter.