About 4.5 billion years ago the Earth was formed. The oldest rocks in southern Ontario are up to 1.5 billion years old and are tens of kilometres thick. Precambrian rocks of the Canadian Shield are visible at surface in Muskoka 'cottage country'. In the GTA the shield is covered by younger rocks and glacial sediments.
Imagine standing in downtown Toronto 20 000 years ago. You would be covered by an ice sheet four times as high as the CN Tower.
Yet, at the same place about 12 000 years ago when the ice sheet had melted back to Kingston you're now underwater. The ice-blocked St. Lawrence Valley cannot drain and Lake Ontario is 50 metres higher than today.
So you escape to the high ground of the Niagara Escarpment. Did you know that the rocks of the escarpment were deposited in a tropical sea over 420 million years ago?
The geology below the ground and the landscape of the surface create a geoscape. Our geoscape influences natural conditions such as climate and flow of water and provides natural resources such as groundwater, forests, agricultural land, and construction materials.
Our quality of life therefore depends on understanding and effectively managing our geoscape.
