"Timothy Demko" skrev i en meddelelse
...
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 at the edge of
the picture, there are some interesting curvilinear features that look
like a ropey surface.

The curvilinear feature looks like a
dissolution/precipitation-mineralisation to me

On the other hand, I could also convince myself
that those features also look like an oblique section through very
large-scale trough cross-bedding (i.e. in a sandstone)...which would be
very, very cool if it is!

We'll soon be able to tell

In the meanwhile
What's the significance of a solid rock?

1) A fused volcanic ... a possibility
2) Cemented particles (being it layed out by wind, water or ejected)
Diagenetic processes is thorughly studied on Earth - all involving water.
What process would be working if not water?

/Carsten