Prairie region
LANDFORM
region
8,000-11,000 years ago when the glaciers were receding this ecozone became mostly treeless grasslands covering the southern third of what is now Alberta, Saskatchewan, and Manitoba. The glaciers leveled the ground and made the prairies a mostly flat surface. The features I will talk about today are mostly surface land formations that were caused by glaciation.
There are 7 main features found on the Praries landscape 1. Moraine 2. Kettle ponds (Prairie pothole) 3. Coulees 4. Boulder 5. Lawstrine plain 6. Salinified pond 7. Shale outcrooping Moraine Moraines are deposits left behind by a glacier. They are made up of till which is a mixture of clay, silt, sand, pebbles, cobbles and boulders. The most common type of moraine found on the Prairies is the hummocky moraine. Hummocky means hump or ridge. kettle ponds (Prairie potholes) A kettle (kettle hole or pothole) is a shallow, sediment-filled body of water formed by retreating glaciers or draining floodwaters. A kettle hole becomes a lake when it is fed by an underground surface stream or river. There is a pothole region on the prairies. It is in the northern Great Plains and includes three Canadian provinces - Saskatchewan, Manitoba and Alberta - and goes into 5 U.S. States. Most of the potholes are filled with water by snowmelt in the spring. They are not lakes because they are not fed by a stream or a river. Coulee Coulee is a French Canadian word meaning "to flow" A coulee is a valley or a drainage zone. This is a low area of land between hills or mountains, typically with a river or stream flowing through it. Boulders A boulder is a rock that is at least 30 centimeters in diameter. Erratics are a type of boulder that are usually different from the bedrock of the area they are found in. Boulders are picked up by the ice sheet when it is advancing and are deposited in a different area as the glacier is retreating. Lacustrine plain A lacustrine plain is a plain that originally formed in the bed of a lake. The bed of the lake is filled with incoming sediment and then the water drains from the lake leaving the sediment behind. In the prairies, the sediment turned to fertile soil and became excellent farm land. |
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Photo used under Creative Commons from starmist1