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

A Closer Look at the Great
Lakes – St. Lawrence
Lowlands
• 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 14 500
years ago
• 14 000 years ago the glaciers started to
melt and retreat north
• As they retreated they scraped giant low
spots in the land and melted ice filled in
the holes
• 11 000 years ago Lake Superior, Michigan
and Huron were all one lake
• By 6000-4000 years ago all of the lakes
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 Escarpment