Da Yoopers Guide to Michigan Stromatolites

Stromatolites are Formations built by Fossilized Algae. The Stromatolite Formation shows the life processes of Fossil cyanobacteria (formerly called blue-green algae). The primitive cells (Prokaryotic type), lived in huge masses that would form floating mats or extensive reefs. Masses of cyanobacteria on the sea floor deposited calcium carbonate in layers and domes.

Stromatolites were thought to have been extinct until forty years ago. However, with the discovery of modern stromatolites in Shark Bay, Australia, and elsewhere, it is now known that some are actually comprised of living cyanobacteria that grow on top of each other at a rate of 1mm a year. These examples are sometimes called "living rocks."

During Earth's early evolution, cyanobacteria was responsible for the formation of much of the planet's free, breathable oxygen, which allowed for the development of oxygen breathing organisms.

Michigan Stromatolite Information

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Marquette County Stromatolites
found in The Kona Dolomite Formations of the Kona Hills in Marquette County, Michigan, have been dated back to around 2.1 to 2.2 Billion years ago.

The colors can vary considerablely due to the billions of years in which many minerals have perculated through the formations. Often they are colored Blue-Green, but they can be found in almost any color combination. Da Yooper has found them in Yellow-Blue, Pink-Blue, and many other combinations of color.

Domes, Arches and Spheres are some of the more rare forms of the Stromatolite formations and are highly sought by collectors..

More Info. Coming

Thrombolites: Thrombolites are cryptalgal structures that, unlike stromatolites, do not have a laminated structure. Instead, thrombolites exhibit a macroscopic clotted fabric (Aitken, 1967; Kennard and James, 1986). Millimeter- and centimeter-size clots of microbial origin are separated from one another by patches of mud to sand-sized sediment. The clots are generally thought to represent microstructures formed by the in situ calcification of calcareous algae and cyanobacterial communities (Aitken, 1967; Kennard and James, 1986).Untitled Document

Oncolites: Oncolites are relatively spheroidal, concentrically laminated microbial structures (Aitken, 1967). The microbial mat usually nucleates about some detrital fragment, often a shell fragment or a sand grain. The term oncolite or oncoid refers to the actual coated grain, although oncolite is also used to describe a rock composed of oncoids.

Jaspilite, an iron ore is also a Stromatolite formation. Please check the link for Jaspilite.

Another formation is at Horseshoe Harbor East of Copper Harbor, Michigan

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