Cyanobacteria and Oxygen. Stromatolites are created by cyanobacteria, also called blue-green algae. These microscopic life forms are not really algae at all but bacteria that have the ability to carry out photosynthesis.It is the process of photosynthesis combined with the growth of the cyanobacteria that creates the distinctive dome-shaped, finely layered rocks we call stromatolites.his was transformed because cyanobacteria could photosynthesize to make its food. The process of photosynthesis uses carbon dioxide and produces oxygen as a byproduct. Billions of cyanobacteria producing oxygen, constantly, over many millions of years made an atmosphere that could support life as we know it.
Sequence Boundary. The sequence boundary is an unconformity updip and a correlative conformity downdip. Where it is an unconformity, it is a surface of subaerial exposure and erosion; however, the expression of those features in an individual outcrop may or may not be obvious.he transgressive surface represents the first major flooding surface to follow the sequence boundary and is usually distinct from the relatively minor flooding surfaces that separate parasequences in the lowstand systems tract.
unconformity. sequence s are enveloped by sequence boundaries (SB) that are identified as significant erosional unconformities and their correlative conformities. These boundaries are the product of a fall in sea level that erodes the subaerially exposed sediment surface of the earlier sequence or sequence s.he Hunt and Tucker (1992) suggest that this  sequence boundary  over the forced regression does not match Mitchum's (1977) original definition of a sequence boundary or its time equivalent marine correlative conformity that was tied to the onset of a sea level fall.