Robert,

Could you be a little more clear in your posts about what are your own suggestions, and what claims the cited authors are making?

The way you wrote it, I first thought that a new JPL update was proposing water-formed dunes and fumaroles.

Then I thought you were quoting Farmer from ASU about water-formed dunes and fumaroles.

Then I realized that there is nothing from JPL about these being water-formed dunes, and Farmer was talking about hematite formation in general, not suggesting there are fumaroles here at Endurance.

As for your theory, how the heck do you get large sand dunes to form at the bottom of what would be a small pond? How would the water move quickly enough to form dunes -- at best it could swirl around like in a toilet bowl -- how you would get that started is quite a problem -- and that sure wouldn't leave the dune pattern we see.

In fact, can you even get sand dunes with that morphology to form underwater? It seems like the amplitude : wavelength ratio is wrong and the slopes are too steep. Sand ripples formed under water should be more gentle. Flowing water would rip those sharp, closely spaced dunes up in a hurry.

They look just like other dunes we see that I think everyone could agree are wind formed, so what's different about these? As for the little ripples not in a line, the crater may disrupt wind flow, or the dunes themselves might create eddies.

Or, maybe the prevailing wind pattern has changed since the one that formed the large ripples, and you're now seeing the beginnings of something else. Even a variation in wind direction seasonally could produce that.