Detrital grains probably occur between or among stromatolitic
Cascade tufa manifest well defined stromatolitic
lamination as evidence of periodic changes of physical factors, crystallization order and biological activity, due to different amount of organic material specially bacteria and cyanobacteria.
1967, Distribution and structure of Recent stromatolitic
algal mats, eastern Andros Island, Bahamas: Annales Societe Geologique Belgique, Bulletin 90, p.
Beating these caveats in mind, data currently available indicate that stromatolitic
microbial ecosystems, evidently including cyanobacteria and other members of the bacterial domain, were extant [approximately]3500 Ma ago (4, 5); methanogenic archaeans by [approximately]2800 Ma ago (6, 7); and gram-negative sulfate-reducing bacteria as early as [approximately]2700 Ma ago (8) and possibly earlier (9).
This portrayal of the environment in which stromatolitic
communities flourished billions of years ago is a classic one.
Historical data records phosphate grades in massive sandstone in the range 5-24%, with stromatolitic
phosphorite uniformly around 29-34%.
It is typically white to grey and light green, banded, and locally stromatolitic
, calcareous to dolomitic marble interbedded with pelite, fine-grained quartzite, minor conglomerate, and mica schist.
They form a stromatolitic
fabric with intercalated lenses of fibrous calcite/aragonite (Fischer et al.
Three generations of infillig are recognized in these cavities, separated by discontinuities, hard-grounds and/or stromatolitic
crusts (Melendez et al.