Chapter 14 Flashcards
What is weathering?
the process of breaking down rock and minerals. Weathering is caused by Sun’s energy, wind, running water, ice, chemical reactions, and the actions of organisms.
What is the difference between young mountains and old mountains?
Young= sharp peaks, no vegetation at the peaks. Old= round peaks, not that tall, and there is vegetation.
What is mechanical weathering?
the process of breaking down rocks and minerals into smaller pieces by physical force. Also called physical weathering.
What is chemical weathering?
the process of breaking down rocks and minerals by chemical reactions.
What two main sources of energy cause weathering?
the Sun and Earth’s internal energy.
What is the difference between the Sun and Earth’s internal energy?
The Sun= drives our weather and the water cycle.
Earth’s internal energy= results in the movement of lithospheric plates on Earth’s surface.
How is gravity important in weathering?
important process because gravity causes water and pieces of rock to move downhill.
What is frost wedging?
mechanical weathering that results from freezing water.
Where does frost wedging occur?
occurs in areas with available water and temperatures that fluctuate around the freezing point.
What is biological weathering?
Weathering by plants and animals.
When does mechanical weathering happen?
weathering by plants occurs when roots grow into cracks in a rock.
What is root wedging?
roots exert force on the rock as they grow and may cause the rock to split.
How do animals cause weathering?
Animals cause mechanical weathering when they dig into soil or burrow underground.
What is exfoliation?
Exfoliation is a weathering process that results in rock layers peeling away. Outer layers peel away first, and then the layers underneath expand and get weathered themselves.
How does wind cause weathering?
Sand gets blown around in the wind and chips away tiny bits of rock from the surface of exposed rock.
What is a hoodoo?
A hoodoo is a tall pillar that forms when wind weathers down large rocks. (See page 329 for a picture in the bottom right corner of the page)
What causes chemical weathering? (4 things)
- water and minerals
- acid rain
- oxygen in the atmosphere
- weathering by plants
How can water and minerals cause chemical weathering?
water can react with minerals in the rock and cause chemical changes. (example: feldspar reacts with water to make clay)
How does acid rain cause chemical weathering?
Acid rain happens when pollutants in the atmosphere mix with water and form an acidic solution. That acidic solution comes down as rain and weathers rock.
How does oxygen in the atmosphere cause chemical weathering?
Oxygen in the atmosphere changes metals in minerals through a process called oxidation. Example: oxygen combines with iron to make rust.
How can plants cause chemical weathering?
Moss and other plants can cause chemical weathering because they release chemicals that cause the rock to break down.
Can chemical and mechanical weathering happen at the same time or do they have to happen separately?
They can happen at the same time.
What factors affect the rate of weathering? Give reasons/examples
1) weather and climate. Ex: rocks weather faster in warm, humid climates. The weather slower in dry, cold climates.
2) Plants and enimals. Ex: plants growing or animals digging can change how much of a rock is exposed to weathering
3) minerals. The kind of minerals on a rock changes how fast the rock weathers. Ex: marble weathers faster than grainte.
4) Surface area. More exposed surface area –> weathers faster.
What is erosion?
the process of moving sediment by wind, water, ice, or gravity
