Victoria Annulus, Discusions about Victoria's Apron Options

[RNeuhaus]

From today, Oppy will start to head toward the Victoria Crater which is about 500 meters away. The drive would take about one month (that is 15 soles of driven with an average of 33 meters/sol, the other 15 soles would be for other purposes or restrictive soles).

The surface around Victoria Annulus, I seems it won't be as smooth as the way between Eagle and Endurance craters but the surface would have no uniform or parallel wave of sand and dust in small size of ripple. See Phil's Victoria Annulus partial map, Tesheiner's one Victoria Crater picture

Otherwise, the surface might have ripples smaller and alike to the ones of El Dorado, on the skirt south side of Columbia Hill. Besides, the Anuulus has no outcrops except to around of few small mini-craters.

This is a change of morphology of surface around the Victoria Annulus. What does it explain about this developing kind of surface of sand? Its extension is just around the inside of Victoria's ray of ejection. That is coincidence. Around that has no bigger ripples as the outside of Annulus.

The explanation would be that around annulus has smoother rock or outcrop surface, no blocks which had not helped to build ripples by the winds. Other factor, I am not sure, is that the slope from the border of Annulus to crater is positive (going up by few meters), then this might be another factor not to build ripples. I have seen that anywhere in the desert that have a slopes does not have any ripples but only flat surface.

Any debate about why the Victoria Annulus does not look like ripples as the outside of Annulus.

Rodolfo

[Bill Harris]

Aldebaran, your analysis is correct, I was having trouble expressing that. I believe that the interaction between water and salts is involved but there is not enough water involved to make liquid anything. I live in the humid southeast USA and many of my views are shaped by living in a dripping atmosphere. In my office I have a piece of pyritic sandstone where the pyrite is reacting with water (etc) to make iron sulfate salts (et al), which in turn pull enough water from the air to sustain the pyrite+water+air=nasty stuff reaction.

But this is the eastiest explanation of the duricrust.

Tom, I don't think we'll ever NOT see white stuff on Mars and even without seeing the chemistry of it I'd suspect that it is a sulfate salt. Sulfides weather to sulfates and unless you have a lot of water to carry it away the salt tends to accumulate. We've see the light-toned material in the looser drifts every time we've cut a trench to purgatory...

Looking at the recent Navcam images I notice that the wheel tracks are light-toned and I suspect that the sand is very thin at this location and we are seeing a reaction zone at the sand-evaporite contact. We need a RAT hole in the wheel scuff.

Again, speculation on my part based on a lot of visual cues/clues and minimal data. Still, the truth will prove to be stranger than reality here on Mars...

--Bill