Actually, a number of us noticed the similarities between those features and "pack ice" several years ago. There are striking similarities, but notable differences as well. Also, some problems with the age relationships to the Medusae Fossae Formation (overlies the 'platy flows' in places). Then, there's the "problem" that they are near the equator, and ice isn't stable at the surface. It might be possible to retain the morphology as "pseudomorphs", if the ice was dirty, but this still doesn't fit with the observation that it's being exhumed from beneath the MFF.

And, as was pointed out above, they also do resemble rafts on very low viscosity lava flows - though scale is a problem with that interpretation.

Bottom line is that I and my colleagues who noticed this years ago didn't feel that the subject was quite "ready for prime time." The jury is still very much out on the nature of that material.

-Tim.