Ancient Mars May Have Been Less Wet Than We Thought - Gizmodo

“Our study challenges the widely held view that most valley networks on Mars were formed by rivers fed by precipitation,” explained Gordon Osinski, a co-author of the new paper and a planetary geologist from Western University, in a Western press release.

“While we found evidence consistent with a small handful of valley networks having formed in this way, our observations suggest that the majority formed beneath ice sheets.”.

For the new study, Osinski, along with Anna Grau Galofre from Arizona State University and Mark Jellinek from the University of British Columbia, examined satellite photos of 10,276 individual valleys found in 66 valley networks on Mars, which they did using custom-built software.

Their algorithm was able to match surface features to specific erosional processes, including glacial, subglacial, fluvial (surface water), and sapping (ground water) erosion.

Of the 66 valley systems studied, the researchers identified 22 as being formed from subglacial erosion: 14 fluvial, nine glacial, three sapping, and 18 indeterminate.

These findings are “the first evidence for extensive subglacial erosion driven by channelized meltwater drainage beneath an ancient ice sheet on Mars,” said Jellinek in the ASU press release, adding that these results “demonstrate that only a fraction of valley networks match patterns typical of surface water erosion, which is in marked contrast to the conventional view.”.

“This is one of those studies that makes us stop and ask ourselves just why did we assume that all the valley networks on Mars were fluvial!

Why wouldn’t both fluvial and glacial erosion have occurred on Mars!