Saturday, October 6, 2012
Wayne DeBrusk of Shuniah Township, near Thunder Bay, has donated a wonderful example of stromatolitic limestone to the Earth Sciences museum. Originally from the Eaglehead Lake area north of Thunder Bay, this boulder was found in a gravel pit. "Strom," as Wayne calls it, is now installed in our rock garden.
Peter Russell posing with the newest addition to the rock garden
Close-up view showing the way they grew layer upon layer upwards as cyanobacteria cemented grains together.
Stromatolite marble or limestone is formed as layers by cyanobacteria or algae in very salty seas. The layers formed as sediment collected on the sticky mat of cyanobacteria.