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What fossils are found in the Gunflint iron formation of Ontario?
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Precambrian
The stratigraphic chart of geologic time.
The Gunflint Iron Formation, a rock layer in western Ontario dating back approximately two billion years, contains a diverse assemblage of microfossils. These fossils provide significant evidence regarding early photosynthetic life and include approximately 30 different types of spheroidal, filamentous, and sporelike forms.12
Classified specimens found within the formation include:
- Filamentous structures: Resembling blue-green algae, these include the genera Gunflintia, Entosphaeroides, and Animikiea.1
- Tiny spheroids: These include the genera Eosphaera and Huroniospora.1
- Star-shaped forms: Assigned to the genus Eoastrion.1
- Umbrella-shaped forms: Assigned to the genus Kakabekia.1
These microorganisms are remarkably well-preserved and share strong similarities with modern microorganisms such as blue-green algae and microbacteria. They represent a critical period in Earth's history, existing during the transition when oxygen first began to accumulate in the atmosphere.2