Erosion and Deposition

1. What happens when a stream slows down?

• The stream picks up larger particles.

• The stream has more energy for erosion.

• The stream picks up more sediment.

• The stream deposits sediment.

The diagram shows the path of a river. Structure A is an oxbow lake, which was originally part of the river. What are the two main processes that formed this river and lake?

• erosion and deposition

• erosion and chemical weathering

• deposition and physical weathering

• chemical weathering and physical weathering

What is the process by which a floodplain forms?

• A stream cuts a new channel during a flood.

• A river overflows its banks and deposits sediment.

• As it enters the ocean, a river slows down and drops its sediment.

• A stream leaves a steep mountain valley, enters a flatter plain, and drops its sediment.

Which statement about floodplains is true?

• Floodplains are an example of stream erosion.

• Floodplains are places where the soil is infertile.

• Floodplains are narrow, steep-walled, and

  V-shaped.

• Floodplains are filled with nutrient-rich soil from deposition.

Which statement best describes the process by which a stream creates a channel?

• The flow of water deposits soil and rock, creating a path for the stream.

• The flow of water erodes soil and rock, cutting a path for the stream.

• Part of a meandering stream is cut off during a flood.

• Gravity causes water to move downhill.

When glaciers retreat, they leave behind huge blocks of ice and deposited sediments. When these ice blocks melt, they can form kettle lakes surrounded by the sediments. What would likely happen if sediment did not build up around the ice blocks?

• The water in the lake would dry up.

• Vegetation would not be able to grow.

• The water would not stay contained.

• Ice blocks would not be warmed enough to melt.

Today scientists use a tool called seismic reflection to study the layers beneath the Mississippi River delta. This helps them understand the formation of the delta. They use their observations to reinforce their understanding of how deltas formed earlier in Earth’s history. What conclusion can the scientists draw?

• Deltas did not form in the past.

• In the past, deltas formed differently from the way they form today.

• Deltas formed throughout Earth’s history in the same way they form today.

• Scientists cannot draw any conclusions about how deltas formed in the past.

The diagram shows how sediment is deposited as a fast-flowing river reaches a flatter area of land.

• river delta

• floodplain

• alluvial fan

• oxbow lake

Canyons, caverns, channels, and valleys all form because of erosion by water. Which landform listed is formed mainly because of erosion by groundwater?

• a broad valley

• a narrow canyon

• a human-made channel

• an underground cavern

In places where there is loose sediment and strong wind, the wind can pick up the sediment and carry it. When the wind slows, it deposits the sediment. Which type of sediment will be dropped first as the wind slows?

• the biggest

• the lightest

• the smallest

• the heaviest