Unit 5 Soil

What is mechanical weathering?
Occurs when Physical forces break rock into smaller and smaller pieces without changing the rock’s mineral composition.
What is frost wedging?
After many freeze-thaw cycles, the rock breakes into pieses by a process called frost wedging
When water freezes, its volume…..
Its volume expands by about 9%, exerting a tremendous outward force. This force is great enough to burst water pipes during the winter.
Which of the following is NOT associated with mechanical weathering?
Reactions with oxygen
What is chemical weathering?
Chemical weathering is the transformation of rock into one or more new compounds
Which of the following is the result of chemical weathering?
A rock that has been changed into one or more new compunds
The atmospheric gas that forms a mild acid when dissolved in water is….
Carbon dioxide
What would cause the inscription on a marble gravestone to become harder and harder to read over time?
Chemical weathering
What climate does chemical weather favor the most?
Climates with high temperatures and abundant moisture
What are the major components of soil?
Mineral matter or broken down rock, organic matter or humans, which decayed remains of organisms, water, and air
A soil’s texture is determined by….
You use categories of clay, silt, and in the soil
The main source of organic matter in soil is…..
Plants
Use figure 5-1 to determine what a soil called if it has 20 percent clay, 60 percent silt, and 20 percent sand.
Silty loam
What are the proportions of clay, silt, and sand shown at point B in figure 5-1?
Clay 20%, silt 40%, sand 40%
What are the proportions of clay, silt, and sand at point A in figure 5-1?
Clay 60%, silt 20%, sand 20%
What are the proportions of clay, silt, and sand at point C in figure 5-1?
Clay 10%, silt 20%, sand 70%
A soil associated with the hot and wet tropics is….
Laterite
Pedalfer soils with contain high amounts of….
Iron oxide and aluminum-rich clays
The process responsible for moving material downslope under the influence of gravity is called…
Mass movement
What is the force behind mass movements?
Gravity
A mass movement that invoves the sudden movement of a block of material along a flat, inclined surface is called a….
Slide
Which of these factors affects the rate of weathering?
All of the above
Why can the removal of vegetation trigger mass movements?
The plant roots bind the soil and regolith together
In the process of…., water freezes and expands, enlarging cracks in rocks.
Frost weging
A large pile of debris that forms at the base of a slope is called…..
Talus
What is the most important agent of chemical weathering?
Water
What is regolith?
Layer of rock and mineral fragments, which covers nearly all of the Earth’s land surface.
The force that drives mass movements is ……
Gravity
What is the content in the soil type Pedocal?
Abundant calcite or calcium carbonate and are typically light gray-brown.
What is the location and content of the soil type Laterite?
Found in hot,wet tropical areas. Iron oxides and aluminum oxides are present.
One of the most dramatic triggers of suden mass movements is a(n)…..
……., the slowest type of mass movement, invoves the lifting and contracting of soil particles over time
Creep
What are three factors that affect the rate of weathering?
Mechanical weathering, rock characteristics, and climate
How are soils classified based on texture?
You use the percentages of clay,silt, and sand
Explain the three processes that break rocks into smaller pieces during mechanical weathering?
Frost wedging, unloading, and biological