Gunflint Chert Microbiota
Precambrian (Paleoproterozoic)
Gunflint Iron Formation
Schreiber, Ontario, Canada

Microscope thin section slide with 1.88 billion year old microfossils

The Gunflint microbiota is an exceptionally ancient fossil community of microorganisms preserved in rocks from the Gunflint Formation of Ontario, Canada. It is about 1.88 billion years old, making it one of the most important windows into early life on Earth and well over a billion years older than the Cambrian!

The biota is a collection of fossilized microorganisms preserved primarily in a type of rock called Gunflint Chert. Since no macroscopic animals existed yet, the fossils are mostly microscopic and include forms interpreted as:

Cyanobacteria
Other bacteria
Filamentous microorganisms
Spherical and rod-shaped cells
Possible microbial colonies

Some specimens are preserved so well that researchers can see individual cells and chains of cells. The fossils were discovered and famously studied by paleontologist Tyler van Andel and, especially, Barghoorn and Tyler in the mid-20th century, helping establish that Precambrian rocks could contain recognizable fossil microorganisms.