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Smothering of microbial mats... something for Ediacaran palaeontology to bear in mind

on . Posted in Published

microbialmats

Microbial mats have been widely invoked as being part of the mechanism by which the soft bodied Ediacara fauna are preserved. Consensus seems to be settling upon microbes growing upon the surface of dead ediacarans forming a kind of death mask that allows the unmineralized tissues to be exceptionally preserved.

This laboratory experiment turns that somewhat on its head.

By placing a piece of seaweed on a well established microbial mat we found that it was possible to smother the mat, and produce a negative impression on the matground surface in the shape of the seaweed.

Had we chosen a body tissue in the shape of an ediacaran body fossil such as Charnia, we could have produced a negative cast of the shape of the fossil on the sediment.

By repeatedly moving the body tissues, we could produce any number of self-similar impressions.  This potential fossilization mechanism could account for some "multi-foliate" ediacaran fronds, and also some purported examples of mat-smothering behaviour by Dickinsonia and Yorgia that have been invoked as evidence for locomotion in the Ediacara Fauna.

Just something to bear in mind.

 

McIlroy, D., Brasier, M.D. & Lang, A.S. 2009. Smothering of microbial mats by macrobiota: implications for the Ediacara biota. Journal of the Geological Society, London, 166, 1117-1121.

http://jgs.lyellcollection.org/cgi/content/abstract/166/6/1117