Jon, thanks for your taking the time to reply to my "out on a limb" view of Mars.
A few additional comments, in reverse order.
6)The nodules were presented as an alternative model to the concretion model.
You will notice I joked about the branch cracking. Of course I'm not claiming the spherules are manganese nodules -- I'm simply pointing out another route to creating a zillion almost uniform spherules over a very, very large area.
The conditions you cited for manganese nodules are precisely the ones I thought applicable to Merdianni: A shallow sea with no suspended particles -- just a giant beaker of mostly chemistry!
I don't see any sedimentation at all there -- I see evaporation and precipitation out of solution.
Er, how deep and how long was the Eagle formation when the spherules concreted?
Doesn't their uniformity bother your geological nose?
I have several examples of Earthly hematite spherules sitting on my desk -- along with Ordovician sandstone spherules ( Thanks Robert ) -- and not one displays the uniformity of the Martian spherules!
I think the spherule question will not be settled until a sample return mission -- I, for one, most likely will not be here to appreciate the results.
5) Evidence of Drape:
Warning: 3.1 MB links.
This is what got me starting to think about the time order of events. The layers on the two eroded rocks follow the contour of the crater.
I would suggest a good stereo viewer like StereoPhoto Maker to view the details on the lip of the crater.
I will break here and start another post.
