Hi Carla

"Carla Schneider" skrev i en meddelelse
...
Ron wrote:
snip
Any guesses what they will find in the trench ?

Crushed basalt - judged on the general dark colour of the tracks the rovers
leave behind.
As to the hematite I believe that - from whatever wet watery circulation, it
is a surface-precipitate. As a surface-feature it is vulnerable to the windy
abration that also may scatter it as dust to other parts of the surface.

I bet they will not find a lot of hematite below the surface,

That would make the general raised values an attribute to wind-action
depositing the stuff at one favoured spot - that seems less likely.

because it is concentrated in the spheres and the spheres are only
lying on the top.

Wouldn't that imply different modes of origin for the spheres - the
light-colored solid exposure seems to be composed of spheres but are low in
hematite.

There are no sand dunes like at gusev crater, because the spheres
prevent them from forming - is this possible ?

No. But there has to be a certain amount of moveable sand - it may have
blown elsewhere

Could there be an other reason as density that prevents these spheres from
beeing
burrowed below the dust, maybe some electrostatic effect ?

I don't think so. I have 'so to speak' introduced electrostatics to account
for the cohesion of the soil we saw at the early pictures. I ment it as a
substitusion for chemical reactions that has not happened, but would have,
had water been present - because of the large surface-area of (and
presumably large stock of) dust. It may however reveal a cerious gab in my
understanding of chemistry.

If the spheres were very light the wind would blow them to dunes, if they
were heavy they would be buried below the dust, and there is a lot of dust
falling down if you wait long enough...

Judging geology by pictures has a lot of drawbacks - it's not easy to 'see'
the density of one sphere.

Carsten