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
