Timothy Demko wrote in
:

mlm wrote:
Timothy Demko wrote

My first impression of the much-talked-about Meridiani outcrop is
that it looks like a fractured, platey basalt flow, maybe even
pahoehoe. In the upper right hand corner of the PanCam image, right

Well, today's (1/27) briefing was very enlightening! The new PanCam
images definitely show fine-scale lamination, and the rest of the
panorama shows some very nice trough cross-bedding/cross-lamination!
I'm suprised that they had Andy Knoll (a paleontologist) did the
briefing, rather than John Groetzinger (a sedimentologist). Andy did a
great job, though, of explaining the significance of cross bedding.

http://marsrovers.jpl.nasa.gov/galle...20040127a.html


My speculation: cross-bedded sandstones, probably small-scale trough
cross-bedding from migration of 3D ripples. And yes, subaqueous...
--
Tim Demko
http://www.d.umn.edu/~tdemko

The new colour panorama of the outcrop lends even more depth to the
structure -- it is much too "red" though don't you think. The 3-D images
from yesterday gave good perspective on the shape, including an
interesting "bowl" at the far right of the face -- maybe a secondary
crater(?).

If you look at the descent images (DIMES) taken just before landing, they
show an interesting, brightly ringed crater (much larger that this MER's
hole) with what must be an even larger outcrop of bedrock at its bottom.
It looks to be quite a deep impact structure so observing strata down
there would be a real coup.

There do certainly appear to be fine layers in the hi-res photos Tim.
But stromatolite is a bit far fetched wouldn't you say? Imagine though
if you are partly right and it is sandstone -- that is a very exciting
prospect. You'd expect to find cherts and larger-scale crystalline
quartz as well if there was sandstone wouldn't you? Maybe it is

Oh lets go nuts and call it a slab of Martian marble -- what a truly
stunning dining room table it would make! Now that would be the find of
the century.

It is awe-inspiring to be at the brink of this discovery and be able to
sit here speculating.

Mark