I have considered the possability of them just being a sand formation or rock but am unwilling to completely accept that yet.
For example: my looking at the first image below. If the gas were moist or other solid or liquid particulate matter, it would most assuredly leave a
wet spot and or a sediment buildup.
This does not appear to be the case, although in the dual-plume, there is a area downwind that may appear to have a fine dust overlay within a certain
area of the plume jet.
Now if this were a dry area of soil, maybe containing fine particle soils, a gas venting, would possibly not leave much other than a fine dusting of
dry soil dust, as the visible plume. The gas would disperse in the atmosphere, and the fine dust may just blow away when windy enough.
Alot of assumption of events, but again, look at the two images below...
Light Grey - plume scope and area of coverage
Light Blue - the dust field accumulated (more noticable on the double plume, probubly more gas & volume)
Dark Blue - this shadow is either cast by a rock or the plume. I feel it is the plume, and more noticable on the double plume, becouse of more
particulate matter within the plume. If you will notice, the shadow itself seems opaque, compared to the sharp contrast of shadow on everything else
around.
Yellow - Arrows indicate areas where it appears to be opaque and the background objects can be seen thru the plume tail.
Red - This 'Bloom' are on both sets of plumes, and look very similar in shape and position to where the alleged plume appears, when the wind
bends the gasses and dust, and blows it sideways. Very similar to a water hose on a winshield, the bloom is at the point the stream of water hits the
winsheild.
I am still looking at the original image, and have yet to find any similar looking anomolies, unlike the dunes or rocks that can be easily discerned
as such, by a close look and the fact that their signatures are common and easy to find elsewhere.
I have also considered the fact that the solar warming of the day, could also be in effect, causing afternoon eruptions of temporarily warmed and
released gasses.
This would also lend to a lack of consistant 'buildup' of significance.
But I am definatly not ready to dismiss it as a rock just yet. And a gas plume of planetary 'burps' ought to be expected of any planet, including
earth.
..
[Edited on 17-3-2004 by smirkley]