[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Microbially induced sedimentary structures



So, its not dinosaurs, but it is paleontology... so I hope its fine for this 
mailing list:

Recently I was in a forum discussion related to microbially induced sedimentary 
structures - specifically, how easy they are to identify, and how common they 
are in pre-cambrian sedimentary rock.

I was under the impression that before motile multicellular organisms were 
around to break up microbial matts, that they covered the earth pretty much 
anywhere it was wet, and furthermore that pre-cambrain rocks often preserved 
this (such as the "elephant skin texture" often seen around the multicellular 
ediacaran biota).

The ultimate focus of this discussion, however, was about Gale crater and Mars. 
There are many many many examples of layered sedimentary deposits visible in 
the photos from the Curiosity rover... none of which looked to me to even 
suggest that there were ever biofilms there.

However, just now, a paper came out:
http://online.liebertpub.com/doi/pdf/10.1089/ast.2014.1218
Hypothesis Article

"Ancient Sedimentary Structures in the <3.7Ga Gillespie Lake Member, Mars, That 
Resemble Macroscopic
Morphology, Spatial Associations, and Temporal Succession in Terrestrial 
Microbialites"

And I must say, most of the pictures are unconvincing to me, 
However, their figure 6 did pique my interest ( 
http://www.astrobio.net/wp-content/uploads/2015/01/fig5.jpg - it says fig 5 on 
the website that hosts it, but its fig6 in the paper)
but I'm far from educated about what to look for (perhaps something like this 
is too optimistic: 
http://upload.wikimedia.org/wikipedia/commons/thumb/9/92/Runzelmarken.jpg/1280px-Runzelmarken.jpg
 )

I was wondering if anyone here would be better able to evaluate the claims, and 
perhaps answer my above questions about the prevalence of pre-cambrian MISS 
fossils.