[X] My Assistant

[Doc]

Hi all, long time no see.
Yet another theory to explain the origin for the bedrock encountered by Opportunity.
I first heard of this new theory from Universe Today;

http://www.universetoday.com/2009/02/16/ne...t-mars-equator/

An abstract is available at http://www.nature.com/ngeo/journal/vaop/nc...bs/ngeo438.html

The theory is interesting, but I would really be interested to know how it explains the spherules seen by Opportunity not to mention the vugs.
Thoughts any one?

[imipak]

I have to say that for a feature so vigorously celebrated by the MER P.I.s, clear examples of festoons have proven to be 'rare birds'. I was hoping the walls of Victoria Crater would provide a few examples.

I may be mis-remembering, but I thought unofficial identifications had been made? See, e.g,. http://www.unmannedspaceflight.com/index.p...ost&p=82403 ;
http://www.unmannedspaceflight.com/index.p...st&p=106462

I could have sworn festooned cross-bed forms had been spotted in the ramp surface at Duck Bay, and in Cape St Mary / Cape Verde?

[dburt]

... I could have sworn festooned cross-bed forms had been spotted in the ramp surface at Duck Bay, and in Cape St Mary / Cape Verde?

Yes, and apparent festoon-like features are also exposed towards the lower right of Cape Victory, imaged just before Victoria Crater was left behind last October:
http://qt.exploratorium.edu/mars/opportuni...G3P2365R2M1.JPG
As Shaka notes, it is perhaps safest not to make too much of these cape exposures, inasmuch as they were not officially commented upon, and could not be examined up close. Of course, it might have been safest for all concerned if apparent festoon-like features seen in exposures elsewhere had not been commented upon either, because the claims initially made for them seem inconsistent with later data and interpretations.

Paul N. - There's no evidence of any "valley network" associated with any festoon-like feature seen yet, or for any channels or other obvious liquid water-related features at all, which is one reason why Paul Knauth and I are, like you, unconvinced. The ephemeral valley networks seen elsewhere on Mars seem to be associated with considerably older surfaces than the top surface of Meridiani.

-- HDP Don