Ian,

I had similar thoughts.

However the size and shape distribution is unusual..all the tektites in my
collection have very variable shapes. I would have expected to see some more
irregular shapes from melt droplets.

On the "berries" that have been sliced open there dosen't seem to be any
zoning or indeed any kind of structure..the structure is really isotropic.
Some of the weathering features on the rock itself really remind me of very
fine grained micritic carbonate rocks (limestones).

We really need to see the Alpha spec data to check for Ca.

pj



"Ian Goddard" wrote in message
news
"Paul Henney" wrote:

Hi,

I'm a geologist (igneous petrologist) and I'm totally baffled by the
recent
microscopic images from Opportunity.

This is clearly a very fine grained chemical sediment with occasional
detrital grains (Blueberries). Its not detrital, not bedded.
Totally weird.


My hunch is that the Martian "blueberries"


http://www.jpl.nasa.gov/mer2004/rove...s/image-1.html

are meteorite-impact spherules that form as minerals vaporized by
meteorite impacts recondense and cool in the atmosphere. Spherules,
also known as microtektites, are even predicted to be common on Mars: