A Closer Look at the Great A Closer Look at the Great Lakes – St. Lawrence Lakes – St. Lawrence

LowlandsLowlands

• The Landforms of our region were basically formed by glaciers during the last ice age

• The Glacial period ended ~ 10 000 years ago

How do we know it was a glacier? They Leave tracks!

• Glaciers create unique landforms from sediment and erosion patterns.

• They also carry rocks of all sizes for great distances

eg. Many of the large rocks found around here came from the Canadian Shield

• Glacier’s form when snow accumulates year after year without melting

• The snow compresses and forms ice• When the ice is ~ 20 m thick it

begins to slowly flow under the force of its own weight

• As the ice moves it scraps the land and picks up rocks and sediment

• The Great Lakes started to form The Great Lakes started to form 14 500 years ago14 500 years ago

• 14 000 years ago the glaciers 14 000 years ago the glaciers started to melt and retreat northstarted to melt and retreat north

• As they retreated they scraped As they retreated they scraped giant low spots in the land and giant low spots in the land and melted ice filled in the holesmelted ice filled in the holes

• 11 000 years ago Lake Superior, 11 000 years ago Lake Superior, Michigan and Huron were all one Michigan and Huron were all one lakelake

• By 6000-4000 years ago all of the By 6000-4000 years ago all of the lakes had formedlakes had formed

• Many areas of the Great Lakes Lowland have very fertile soil

• This is great for growing crops• Other areas are dominated by clay

soil (especially lambton county)

• The major landform feature of the Great Lakes Lowlands is the Niagara Escarpment

• This is a rocky ridge that runs from Niagara Falls to Manitoulin Island

The Niagara EscarpmentThe Niagara Escarpment