WEATHERING (chapter 5)
I.
Mechanical Weathering
A. _____________________________________________ occurs when physical forces break rock into
smaller and smaller pieces without changing the rock’s mineral composition.
B. In nature, ____________physical process are espeicially important causes of mechanical weathering:
C. _________________________________
a. The mechanical breakup of rock caused by the expansion of freezing water in cracks in
the rocks
b. _______________________ = sections of rock that are broken loose and fall into large
piles, which typically form at the base of steep, rocky cliffs.
2. __________________________
a. A type of pressure release in which overlying materials like rocks are removed (by
erosion, or other processes), which causes underlying rocks to expand and fracture
parallel to the surface.
b. _____________________________ = Reduced pressure on igneous rock causes it to
expand and allows pieces of outer rock to break off in layers.
3. ___________________________________________
a. The activity of plants, digging animals and humans can also cause mechanical
weathering.
II.
Chemical Weathering
A. _________________________________________ is the transformation (change) of rock into one or
more ________________________________________..
1. Chemical Weathering of ________________________
a. Weathering of potassium feldspar produces clay minerals, soluble salt (potassium
bicarbonate), and silica in solution.
b. _______________ remains mostly unchanged.
2. Weathering of _______________________________________
a. Produces insoluble iron oxides and clay minerals
3. __________________________Weathering
a. Makes corners and edges of rock more ____________________________
B. During chemical Weathering, rocks undergo changes in their composition
C. Caused by:
1. _________________
2. oxygen, carbon dioxide, and acids
D. _________________________ - the reaction of water with other substances
E. _________________________- the reaction of oxygen with other substances
1. __________________caused by these two factors breaks rock apart
F. Water causes chemical weathering by absorbing gases from the atmosphere and ground
1. CO2 +Water  ________________________________
a. ________________________ Rocks/Minerals
b. Examples:
i.
III.
Stalactites/Stalagmites ; Limestone caves
Rate of weathering
A. Two other factors that affect the rate1 of weathering:
1. ____________________________________________
a. Mineral composition and solubility
b. Physical features such as joints
2. _________________________
a. _______________________ and _______________________ are the most crucial
factors.
b. Chemical weathering is most effective in areas with ____________ temperatures and
____________ moisture.
B. ____________________________ weathering
1. Caused by differences in ___________________________of rocks
2. Creates unusual and beautiful rock formations and landforms
Weathering Picture Challenge
Picture Mechanical or Chemical Weathering?
1
2
3
4
5
6
7
8
9
1
Rate = how quickly something happens
Vocabulary/Description