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.
In plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other.