Precambrian age South American Stromatolites
Cut and Polished Slices of Precambrian Stromatolites from South America. Stromatolites are one of the earliest fossilized forms of life to be found. They are the result of the building process of sediments and cementations in shallow waters of cyanobacteria, or blue-green algaes. These can be cut to display the layers that have been built up over years and years, in the same way a tree is cut to show its growth rings. Seasonal changes may have slowed down growth or totally the opposite and this can be seen in the varying thickness of layers and different mineral content of each layer over time. Stromatolites can still be found today in places such as Shark Bay in Australia.
The specimens you see below all come from the Eastern Andes, S. Cochabamba, Bolivia, S. America. These are colonial stromatolites. They are dated to an unbelievable 2.2 to 2.4 Billion years old. Yes -That did say Billion! Scientifically, that period of Earth's history is called the Paleoproterozoic.
Size: see photo for scale (Hand held for photographic clarity)