Download Unit 3 Summary Chapter 11 What have we learned so far

Grade 9 Geography of Canada
Unit 3 – Physical Connections
Chapter 11 – Landform Connections – Pages 101-126
Summary - What have we learned so far?
Canada has seven landform regions and three distinct types of landforms:
shield, highlands and lowlands.
A landform region could be described as a region with a geographical feature
that makes it different from the regions that surround it. A geographical
feature could be mountains, vegetation or soils.
CANADIAN SHIELD
The Canadian Shield is Canada’s oldest landform region. The Shield covers
more than 50% of Canada. The Shield was once a very high mountain range.
Today, the topography of the Shield is relatively flat with rounded hills of rock.
The Shield is composed of two types of rock: igneous and metamorphic.
The Shield is called Canada’s storehouse of metallic minerals because of
large deposits such as nickel, copper and zinc. These minerals were formed
by (1) magma containing minerals cooling in the cracks of the Shield or (2)
water dissolving minerals causing separation by mineral density within the
cracks (i.e., high density minerals sank deeper within the Shield cracks, low
density minerals rose to the top of the cracks)
The Shield has thin soils, many lakes, large rock outcrops and vast forests.
The lakes were formed by the gouging action of glaciers. The water sits in
these gouges because the bedrock does not let water pass through it (i.e.,
impervious).
The Shield has the appearance of a saucer (i.e., higher at the edges and
lower in the centre). Hudson Bay is the centre.
LOWLANDS
Canada has three lowland regions: Interior Plains, Great Lakes – St.
Lawrence Lowlands and Hudson Bay-Arctic Lowlands.
Interior Plains
The Interior Plains are part of the Great Plains of North America. The Plains
were formed by sediment deposits from the Canadian Shield and the Rocky
Mountain range pressed into layers of sedimentary rock. The deeper layers
in Alberta and Saskatchewan contain oil and gas, while layers in
Saskatchewan formed during the Mesozoic era contain potash. The upper
layers of soil are deep and rich.
The sedimentary rock may be hard or soft. The softer rock erodes more
quickly. The process is called differential erosion. The different erosion rates
have caused three levels of elevation separated by escarpments to form in
the Interior Plains.
The topography of the Interior Plains is rolling hills and deep, wide river
valleys. The rivers and lakes of the Interior Plains were formed by continental
glaciation.
The Interior Plains are called Canada’s breadbasket.
Great Lakes – St. Lawrence Lowlands (GLSLL)
GLSLL is Canada’s smallest landform region comprising only 14% of
Canada’s land area.
GLSLL has two parts: (1) Great Lakes and (2) St. Lawrence.
The bedrock in this region is sedimentary rock formed during the Paleozoic
era. The bedrock can be seen as escarpments (e.g., the Niagara
Escarpment – it was formed by differential erosion).
The Great Lakes part was formed by glacial deposits of sand, gravel and soils
from the Canadian Shield. The topography is flat plains with glacial hills and
deep river valleys.
Continental glaciation also formed the Great Lakes. The glaciers gouged out
the lakes, and as the glaciers retreated, their meltwater filled the lakes up.
The Great Lakes were originally much bigger, but shrank in size as the some
of the meltwater drained into the oceans.
The St. Lawrence portion is a rift valley formed by faulting.
GLSLL has excellent soils and a relatively warm climate. The area is ideal for
agriculture.
GLSLL is the most densely populated region of Canada. About 50% of
Canada’s population lives here. GLSLL is called Canada Heartland.
Hudson Bay – Arctic Lowlands (HBAL)
HBAL has two parts: (1) Hudson Bay and (2) Arctic.
The Hudson Bay part borders the southwest shore of Hudson and James
Bays. It is flat and covered in swampy forests. The area is a layer of
sedimentary rock on top of the Canadian Shield
The Arctic Lowlands are a series of islands. The topography is rolling. The
ground is frozen for much of the year. The sedimentary rock contains lignite
(a form of coal), oil and gas.
HIGHLANDS
Canada has three highland landform (mountain) areas: Appalachians,
Innuitians and Western Cordillera.
Appalachian Mountains
The Appalachian Mountains are the oldest highland region in Canada.
The mountains were formed by the folding of sedimentary rocks during the
Paleozoic era when North America collided with Europe and Northern Africa
during the formation of the Pangaea. Recall – the rocks in this region are
similar to rocks in Scotland and Wales.
The sedimentary rock is rich in non-metallic minerals such as coal. Areas of
igneous and metamorphic rocks (formed by volcanic activity and faulting)
contain metallic minerals such as zinc and iron.
The topography is rolling mountains and hills with wide valleys. The
Appalachian Mountains have been worn down be erosion. The valleys were
formed by glaciation. The weight of the glaciers also pushed the land
downward creating a “drowned coastline.” As a result, inlets formed along the
ocean.
Innuitian Mountains
This mountain region is located in Canada’s far north. The mountains were
formed during the Mesozoic era.
The rocks are mostly sedimentary containing many minerals.
The climate is extremely harsh. Ice and permafrost cover vast areas.
Western Cordillera
The Western Cordillera Mountains are tall and rugged in appearance
suggesting the region is geologically young.
The mountains were formed by the collision of the North American and Pacific
plates. The heavier Pacific Plate forced its way underneath the North
American Plate. The North American Plate was pushed upward.
The Western Cordillera has three mountain ranges: (1) Coast, (2) Columbia
and (3) Rocky. The ranges run south to north. As well, there are three
landform divisions in the Western Cordillera. The Rocky and Columbia
Mountains make up the area called the Eastern Mountains. The Interior
Plateau is the region between the Eastern and Coast Mountain regions. The
Interior Plateau includes the Okanagan Valley. The Coast Mountains make
up the western edge and include Vancouver Island.
Folding and faulting of sedimentary rock formed the Rocky Mountains.
The Rocky Mountain Trench separates the Rocky and Columbia Mountain
ranges. The trench is a zone of faults.
The Columbia Mountain range is sedimentary rock with many metamorphic
intrusions. Intrusions are the injection of molten rock between and through
layers of rock beneath the earth’s surface.
The Interior Plateau is metamorphic and igneous rock deposited by volcanic
activity. Glaciers have cut large rivers in the rock and deposited sediments to
create excellent farmland such as the Okanagan Valley.
The two ranges of the Coast Mountain area were formed by the movement of
the North American and Pacific Plates. The movement resulted in igneous
and metamorphic rock formations.
The plates continue to move, and this area is Canada’s most active
earthquake region.
During the Ice Age, glaciers cut deep valleys into the rock along the ocean
shore. The valleys were flooded with seawater. The inlets are called Fiords.
GLACIATION
Ice Sheets covered almost all of Canada during the Ice Ages.
There are two types of glaciers: (1) Alpine Glaciers located in mountains and
moving by gravity from high areas to low areas and (2) Continental Glaciers
that occupy great areas of land and move by their own weight.
Glacial features caused by erosion include:
Striations – grooves in the bedrock
Spillways – deep valleys carrying huge volumes of glacier meltwater
Misfit Streams – the remnants of the spillway once the ice sheet had
melted and the area became drier. The misfit stream is much narrower
and shallower then the spillway
Glacial features caused by deposition
Till – material such as clay, sand and gravel deposited by the glaciers.
Till Plain – till deposited underneath the glacier forming well drained soils
good for agriculture.
Moraines – ridges of till along a till plain, but poor for farming because
soils are thin, topography is hilly and land is swampy.
Drumlin – egg-shaped hill with steep side at one end and gentle slope at
the other.
Erratic – rocks carried hundreds of kilometres by the glacier and
deposited.
Esker – steep-sided ridge formed by material deposition from the melting
glaciers.
Great Lakes – formed by gouging of ice sheets.
Lake Plains – fertile flat area once the bottom of lake beds.
Kettle Lakes – formed when large chunks of ice became imbedded in
glacial debris and, when the ice melted, the hole filled with water forming a
lake.