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Unit 4 Lesson 3 Processes that Shape the Land
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Unit 4 Lesson 3 Processes that Shape the Land
Indiana Standards
• 7.2.7 Use geological features such as karst
topography and glaciation to explain how largescale physical processes have shaped the land.
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Unit 4 Lesson 3 Processes that Shape the Land
Run of a River
What landforms can streams create?
• A stream forms as water erodes soil and rock to
make a channel. A channel is the path that a
stream follows.
• Landforms such as canyons and valleys are
created by the flow of water through streams and
rivers.
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Unit 4 Lesson 3 Erosion and Deposition by Water
What landforms can streams create?
• Curves and bends that form a twisting, looping
pattern in a stream channel are called meanders.
• The repeated meander of a stream creates a flat
area called a floodplain.
• When a stream floods, a layer of sediment is
deposited over the flooded land. Because of this,
floodplains are often very fertile.
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Unit 4 Lesson 3 Erosion and Deposition by Water
What landforms can streams create?
• During a flood, a meander can be cut off, forming
a crescent-shaped lake called an oxbow lake.
• When a stream empties into another body of
water, its current slows and it deposits its load.
• A delta is a fan-shaped pattern of deposited
sediment load.
• An alluvial fan is a fan-shaped deposit that forms
on dry land.
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Unit 4 Lesson 3 Erosion and Deposition by Water
What landforms can streams create?
• What landforms can you identify in the image
below? Explain how each type of landform formed.
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Unit 4 Lesson 3 Erosion and Deposition by Water
Waterworks
What landforms are made by
groundwater erosion?
• Groundwater is the water found below Earth’s
surface.
• Acidic groundwater can cause erosion by
dissolving rock. When this happens underground,
caves can form as a result.
• Water that drips from cracks in a cave’s ceiling
leaves behind icicle-shaped deposits called
stalactites and stalagmites.
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Unit 4 Lesson 3 Erosion and Deposition by Water
What landforms are made by
groundwater erosion?
• Sometimes the results of groundwater erosion are
visible on Earth’s surface.
• A sinkhole is a circular depression caused by the
collapse of the roof of a cave.
• Sinkholes are common features in areas with
karst topography, a type of irregular landscape
that forms on soluble rock.
• Karst topography is found in Indiana and other
limestone regions.
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Unit 4 Lesson 3 Processes that Shape the Land
Groovy Glaciers
What kinds of ice shape Earth?
• A glacier is a large mass of moving ice that forms
by the compacting of snow by natural forces.
• Glaciers move downhill by gravity and cause
erosion. As a glacier melts, it deposits the
materials it carries.
• Glacial drift is the general term for all materials
carried and deposited by a glacier.
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Unit 4 Lesson 3 Processes that Shape the Land
What kinds of ice shape Earth?
• An alpine glacier is a glacier that forms in a
mountainous area.
• Glaciers can erode a V-shaped valley caused by a
stream into a U-shaped glacial valley.
• Cirques, arêtes, horns, and hanging valleys are
landforms caused by alpine glaciers.
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Unit 4 Lesson 3 Processes that Shape the Land
What kinds of ice shape Earth?
• Continental glaciers are huge, continuous masses
of ice that may spread over entire continents.
• Continental glaciers flatten and smooth land.
• Erratics, drumlins, and kettle lakes are caused by
continental glaciers.
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Unit 4 Lesson 3 Processes that Shape the Land
Melting the Ice
• During the last Ice Age, an ice dam held back the
water of Glacial Lake Missoula.
• The dam broke and emptied the entire lake at
once, forming huge waterfalls, deep canyons, and
tall ripple marks in the land.
• Lake Missoula reformed and flooded about 40
more times.
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