"Richard I. Gibson" wrote in
message ...
hrtbreak wrote:

Would one expect to see carbonates fixed in rocks when the atmosphere is
rich in CO2? Doesn't the large-scale fixation of CO2 in our atmosphere
into
rock formations require living organisms, like diatoms?

Not to criticize your other speculations, but diatoms secrete
siliceous tests, not carbonate. There are other critters, of
course, that DO turn CO2 into CO3 in rocks.
---clip---
See speculation qualifications below. My point was that if there were
carbonate-based rocks in large quantities, would there be all that free CO2
left in the atmosphere? We don't really know enough to guess what the
environmental cycles on this alien planet are like, but I had to start my
baseless speculations somewhere. Then again, there wouldn't be evidence of
"large quantities", either.

We don't really know how consolidated it is - it may not have had
to be under "extreme" pressure. On earth sediments lithify with
proper cement and not too much pressure. As for the tilting,
maybe by the impact process that formed the crater. Given the
small scale of the outcrop (about 4" they say), those would be
VERY thin lava flows. Possible, yes; probable - ?

When I wrote this, I think they were saying the formation was about a
foot-and-a-half tall. The weird soil mechanics seen around the landers
might be a factor in the formation process, too, I suppose.

Yes, I'm an engineer, but I didn't have anything better to do at the
moment.


JJ Robinson II
Houston, TX
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_____________________________________
Richard I. Gibson, Gibson Consulting
Gravity-Magnetic-Geologic Interpretations
http://www.gravmag.com

301 N. Crystal Street
Butte, Montana 59701 USA
Phone/Fax (406) 723-9639

Education Director, World Museum of Mining
http://www.miningmuseum.org