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

[Gray]

I think Bill might be on the right track. Look again at Nirgal's colorized image of the pebbles:

http://mitglied.lycos.de/user73289/misc/op...24pan_col_d.jpg

Many of the larger grains have a shape that looks like a Hershey's kiss. Some have suggested that they might be ventifacts. But it would take winds blowing equally from every direction to sculpt a grain that way. Unlikely IMO. Bill's suggestion that they may be formed by a melt/impact process makes more sense to me at this point.

One of the grains at the lower left-hand edge of Nirgal's image provides some tantalizing evidence for this idea. The grain is cut by the edge of the image, but you can see that there is a smaller grain (blueberry) contained it a larger grain. It looks as if part of the larger grain has wrapped around the smaller grain.

I'm envisioning a process like this: the meteor strikes the surface of Mars and in the process melts many of the silicate minerals in the crust (it could be a lower basalt or the basalt sands). Molten blobs fly through the air assuming a streamlined, rain-drop shape. The strike the surface while still partly molten. This flattens the bottom but they still retain a streamlined shape in the upper part.
If the grains fell, while partly molten on a surface which was already littered with the smaller blueberries. (A process Bill has already proposed). The under side of the "Hershey's kiss" grain would have the smaller blueberry imbedded in it. That partial view of a grain with the embedded blueberry might be evidence for this.

- gray