|Stromatolites can grow in the form of single columns or domes, and they can range from low relief mounds, bulbous masses or long slender columns with branching extremities.|
In effect stromatolites are
a product of their environment, their growth depends on the amount of sediment
supply, proximity to the photic zone and amount of oxygen. Depending
of the abundance of these factors stromatolites vary in size (from
a few millimetres to a few meters) and shape. In general, ancient
stromatolites have a scale of a few millimetre laminations.
Cyanobacteria are among the easiest microfossils to recognize and the morphologies in the group have generally remained the same for billions of years, and they can leave chemical fossils behind as well, in the form of breakdown products from pigments.