Chapter 5: Weathering, Soil, and Mass Movements

In a soil profile, the _____ layer contain parent material that is hardly weathered at all.

C horizon

What is a false statement about mass movement?

Mass movement ALWAYS leads to landslides. This is false.

Which of the following statements about soil formation is true?

Precipitation affects the rate at which nutrients are removed from soil.

Which of the following is true about mass movements?

Some mass movement is too slow to be seen. (Creep) Gravity is the driving force behind all mass movements. Mass movement is always downslope.

Here are some false statements. The correct word that should go there is in parenthesis.

The longer a soil has been forming the thinner it becomes (thicker) Hot, wet climates produce a thin layer of chemically weathered soil. (thick) Cold, dry climates produce a thick layer of mechanically weathered soil. (thin)

A landform called a stream valley is the most common result of

_____________________ p. 143 of textbook

The air component in soil provides plants with the _____ needed for photosynthesis.

carbon dioxide

When a rock is exposed to chemical weathering, it

changes into one or more new compounds

The inscriptions on marble gravestones become harder and harder to read over time. This is caused by

chemical weathering

____ , the slowest type of mass movement, involves the lifting and contracting of soil particles over time.

creep

________weathering happens when different parts of a rock mass weather at different rates.

differential

Rock features such as the sculpted pinnacles seen in Bryce Canyon National Park are the result of

differential weathering

One of the most dramatic triggers of sudden mass movement is a(n)

earthquake

Name a component that is not a major component of soil?

earthworms

What is not a factor that affects the rate of weathering in rocks?

evolution

In which of the following areas will soil formation be greatest?

flat areas in a warm, wet climate

Which of the following weathering processes involves the constant freezing and thawing of water?

frost wedging

_____ is a dense impenentrable layer found in the B horizon of a soil profile.

hardpan

Pedalfer soils would most likely be found

in the eastern half of the United States

Since humans have been present, the amount of sediments carried by rivers has

increased by a factor of about 2.7

Laterite soils contain high amounts of

iron oxide

A ______ soil is made of equal parts of clay, silt, and sand.

loam

Human activities such as farming, ____, and construction remove vegetation from the land and increase the rate of erosion.

logging

The process called ___________ involves physical forces that break rock into smaller pieces.

mechanical weathering

The process that occurs when physical forces break rock into smaller pieces without changing the rock's chemical composition is called

mechanical weathering

During the process of soil formation, ___________ decompose dead plants and animals, increasing the amount of organic matter.

microorganisms.

Name the 4 components of soil?

mineral matter humus (organic matter-decayed plants and animals) air water

In general, the largest comonent of bog soil is

organic matter

One cause of chemical weathering is the _______ that dissolves in water and then reacts with many common minerals, forming oxides.

oxygen

What kind of soil is found in the C horizon of a soil profile?

partially weathered parent material

Large amounts of calcium carbonate are typical of ___ soil.

pedocal

On a steep slope, erosion is accelerated because there is not enough moisture to sustain sufficient

plant growth

The main source of organic matter in soil is

plants

Which is a factor that affects the rate of weathering in rocks?

rock characteristics climate amount of exposed surface

A mass movement that involves the sudden movement of a block of material is called a

slide (rockslide)

Oversteepened slopes often lead to mass movements because

the angle of their slope is greater than 40 degrees

The soil that forms on unconsolidated deposits is called

transported soil

Chemical weathering is highest in areas that are

very warm and wet

One trigger of mass movements is the pores in sediments filling with ___.

water