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Stromatolith Collenia undosa Walcott 1916

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This is a beautiful stromatolite slice from the deep Precambrian of the USA. It is a slice of Collenia undosa from the approximately 2.2 billion year old band ores (BIF's) of the Biwabik Iron Formation of Minnesota. This piece is characterized by a beautiful high-contrast lamination. In the lower area, the plate also shows the typical iron mineralization of Mary Ellen Jasper. The Site of the Mary Ellen Mine is a classical Banded Iron Formation. Locality. It is knon and valoured for its nice and colourfully preservation. These decorative Stromatolite fossils are sometimes even used for jewellery. The Cyanobacteria that where incorporated in the bounding of this Stromatolite have likely produced significant amounts of oxygen. This free oxygen bond the Fe² that was solved in the ancient oceans. This process produced the Banded Iron Formations (also known as BIF’s ) world wide at that time in earth history. After all the iron was used up by that process the oxygen concentrations in the Atmosphere and ocean could rise. What lead to the great oxygen crisis (sometimes also known as the first big extinction). How ever the higher levels of oxygen allowed the life eventually to become more complex.

	Location:	Mary Ellen Mine, Mesabi Range, St. Louis County, Minnesota, USA
	Size :	about 100 x 55 mm
	Age:	Precambrian, Lower Proterozoic, Rhyacian, Biwabik Formation (about 2.2 Ga / 2200 Ma)

Product no.: 11142