Numerous remains of various coccoid, rod-shaped, and filamentous microfossils were found in stromatolites of the Byuk Formation of the Upper Vendian. All of these are almost entirely covered by a single bacterial film, however, every morphotype is isolated from the other ones by specific zones, which have several specific characteristics (density, absence of microbial relics, and a separate small hollow space out of the entire bacterial film). Such hydraulic forces within the bacterial films can preserve the community from water balance disturbance in the long term, providing a protective layer against mechanical impact. At the same time, they also differentiate isolated colonies of different morphotypes of microbial remains present within the community. This arrangement is not present in most previously studied microbial colonies of stromatolites. This paper discusses the reasons behind the formation of stromatolites with contrasting textural and structural features, which occurred in a small embayment rather than in a large part of the Vendian basin floor.
Litvinova et al. (Mon,) studied this question.