As I understand it, the earth was created about 4.6 billion years ago.
Then, about a billion years later, the first cyanobacteria (also called blue-green algae) appeared. They were single-cell organisms and the very first lifeform that could photosynthesize, that is, they could use the sun's energy to create carbon-based sugar and in the process produce oxygen. That oxygen was released to the amosphere which up to that point was mostly carbon dioxide and other gases.
The cyanobacteria became incredibly abundant, virtually covering the Earth, and over another billion years ended up creating the very atmosphere we breathe today.
They were so numerous when they existed that they created thick stringy mats that became fossils. Those fossils are called stromatolites.
There are three places in Canada where stromatolites are found. One is on Red Lake, in fact, right on the shoreline in front of Bow Narrows Camp and also other locations nearby.
The other two are Steep Rock Lake in Atikokan, Ontario, and near Yellowknife, Northwest Territories.
They are also found in Australia.
This photo, which was taken just down the shore from Bow Narrows Camp, shows the stringers of fossilized algal mats.
For more on stromatolites visit this website at Queen's University in Toronto.
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1 comment:
Stromatolites are found in many more places in Canada than those that you have highlighted. Stromatolites occur in the Gunflint Formation in the Thunder Bay area as well as in the rocks of the Sibley Group, in the Thunder Bay- Nipigon area. And those are the Precambrian ones. There are others that are much younger. They also occur world wide from Morocco to Australia and many spots in between.
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