Subglacial water on Mars Options

[ngunn]

This topic has been discussed here over a spread of time and in various threads but not recently, I think. This article might be a good way to kick off some more discussion from a present day perspective if anyone's interested:
https://www.sciencedaily.com/releases/2020/...00803120154.htm

[serpens]

That is another interesting hypothesis on the formation of drainage networks on Mars but as with all such it should be considered hypothetical rather than definitive. In fact the abstract in Nature states that the study modelling revealed that valley formation involved fluvial, groundwater sapping, glacial and sub glacial erosion with fluvial and subglacial the predominant mechanisms. This is a different picture to that cast by the Science Daily article.

I would make a few observations. In the main the distribution of valley networks does not match the distribution of evidence of glacial activity. The valley networks are distributed in the equatorial and mid latitude range. In the Southern highlands the glacial remnants are generally south of the valley networks and above the equator are to the further north, primarily along the dichotomy (Deuteronius, Prontonilus and Nilosyrtis Mensae). Interestingly, to the South of the Tharsis rise the valley networks are closer to the pole with glacial remnants to their North, closer to the equator, supporting the idea that the development of the Tharsis rise caused tectonic dislocation.

Another point is that the dating of the drainage networks indicates that they were formed over a span of some 200 million years at the boundary between the Noachian and Hesperian periods, pretty much when Curiosity's ground truth has confirmed a warmer wet environment. As with Nick Hoffman's white Mars hypothesis and dburt's impact gardening hypothesis, concepts that look compelling from analysis of orbital data are revealed erroneous with analysis on the ground.