Pity they only did the 456 in 1/4 resolution, but then, for those of an old-school disposition, this is about the resolution that IMP on Pathfinder offered.

Doug

Great mosaic. Out of curiosity, why did you make it in two sections?

Look at the dunes One was taken looking west - the other looking north - they dont actually join up. The 'gap' data will be down before too long I'm sure - but I thought I'd just put that out there as I think they make nice views on their own

It's probably another 3 x 4 to slip in between them.


Doug

Neat images. I look at those and began to wonder how long it takes to bury even a small crater on Mars. Then I started wondering what processes might be generating all that sand. Certainly impacts will generate sand and dust, as will volcanic eruptions, but could there be some other form of mechanical weathering that is contributing to the formation all that sediment?

As always in forming landscapes, it is the sum of all processes involved. We don't have an accurate geologic timeline cq context however.

Suppose that the sediment itself is there (due to impacts, wheathering processes, maybe even water action in the past) and impacts dig holes. Seems to me filling them up again doesn't have to do so much with other impact. The main process to my opinion is displacement of particles by wind action. This proces levels off everything, as long as you wait long enough. Gaps fill, rocks abrade by dust (particle) loaded wind. Add some physical weathering (temp. changes, frost, maybe even chemical processes) that turn rocks into fragments and mass movement (things falling as low as they can)....and all the holes eventually will fill up.

I think a lot of the surficial layer's characteristics have been more affected by wind than by any other force. Both constructionally and destructionally. Yes, volcanic activity, ice and flowing water have obviously had a part in forming the landscape. But those forces have been dormant, or nearly so, over the vast majority of the planet for millions, if not billions, of years.

With what I am sure are extremely rare exceptions, the only things left that continue to shape the surface of Mars are the winds and the occasional impact. And while the air is thin, it can hold millions of tons of dust, enough to blanket the whole planet. That dust gets swirled around and dumped back out, then picked back up and swirled around some more, and dumped back out again... year after year for hundreds of millions of years.

No wonder that many of the smaller impact craters on the planet have been filled in with dust. The amazement would be if a lot of them hadn't been filled in already, I think.

Of course, let's not forget the one other active surface modifier on Mars -- the polar mechanisms. The seasonal freeze/thaw cycle at the poles must create a lot of small-grain particles as a by-product of the process, and of course entrained dust within frozen CO2 does get re-distributed when the dry ice sublimates in the spring... The polar mechanisms have a great effect on the arctic and polar landscapes, I'm sure, but they do also have a certain impact in the dust circulation cycle that affects the rest of the planet. Which, of course, are driven by winds -- getting us back to where we started.

-the other Doug

Great work! I hope you get that missing part pretty soon, it's a very nice scene.