"Doug..." wrote in message
...
In article ,
says...

snip

But we see the same phenomenon in landslides in desert regions on the
earth.
There is evidence that some large landslides will behave as a fluid due
to
the creation of a layer of compressed air between the landslide material
and
the ground upon which it is sliding. Such a layer acts like a lubricant
that reduces friction, and will allow the slide to behave as a fluid. In
the
case of Mars, the air would consist of the CO2 atmosphere. Now, I am
not
saying that water doesn't exist on Mars. Obviously it does, at least at
the
poles. And of course, we have all seen some evidence that there may be
ground water, and/or frozen water in the subsurface. What I am saying
is
that there are other explanations for the fluid appearance of these
landslides on Mars.

OK, George, I'll buy that. Now, explain to me how you get a landslide
on what appears to be topography that is extraordinarily flat for miles
and miles in all directions?

The simple answer is that you don't. The more complex answer is that the
region is a large filled crater, that indeed may have older deposts composed
of landslide fill buried deep within the crater fill deposits. Noting in
the following link that the fill material comes from the northeast, and has
nearly completely filled the crater to the center, and sloping to the
southwest towards the crater wall, I find it highly unlikely that there are
landslide desposits exposed at the surface in the vicinity of Opportunity.
The only likely place where you could view such landslide deposits would be
possibly within the walls and floor of a large crater that has breeched the
surface deposits of the plain. Such a potential crater, in fact is within
traveling distance of Opportunity, and I think they plan to drive there in
the coming weeks.

As I mentioned before, there are no large
craters that would create these "splash" landforms as ejecta, at least
not in the right place to have caused the effects visible in the DIMES
images.

They don't have to be close by. There are so many craters, both large and
small on Mars that any one of them, or at least most of the larger ones
could have ejected material that could travel completely around the Martian
globe, and even sent material into orbit. This material has to come down
somewhere, and just as often as not, it will land somewhere other than in
proximity to where it originated. I would not be at all surprised to find
that material from craters that do exist in the vicinity to have left
material at the Opportunity site. In fact, I would be very surprised if
they didn't.

I'm not saying that water has flowed over or under this surface
recently. It may have been more than a billion years since water flowed
over this surface. But I believe it's very possible that water HAS had
a hand in the sculpting of the surface we're observing, even at very
high resolution.

Doug



What features are present that leads you to believe that flowing water has
had a hand in sculpturing the landscape at the Opportunity landing site
and/or vicinity? And please try to restrict you answer to features that
could only have come from the flow of water, and nothing else.