Weathering Flashcards
What is denudation?
The process of lowering Earth’s land surface through weathering and erosion, reducing elevation and relief.
Denudation involves the removal of soil and rock from the Earth’s surface.
Define relief in geological terms.
The difference in height of land on the Earth’s surface, including mountains, valleys, hills, and plains.
What is weathering?
The breakdown of rocks, soils, and materials through exposure to weather and organisms.
Weathering can occur due to factors such as rain, frost, ice, snow, and wind.
List the three categories of weathering.
- Mechanical
- Chemical
- Biological
What is mechanical weathering?
The physical breakdown of rocks without changing their chemical composition.
Mechanical weathering includes processes like freeze-thaw action and exfoliation.
Explain freeze-thaw action.
A process where water freezes and thaws in cracks of rocks, causing them to break apart.
This action is common in areas with temperature fluctuations between freezing and thawing.
What is exfoliation in the context of weathering?
The process of layers of rock peeling off due to temperature changes, resembling onion peeling.
Exfoliation is a type of mechanical weathering that often occurs in granite.
Where does freeze-thaw action commonly occur?
In areas of high altitude and high latitude.
These regions experience significant temperature variations conducive to freeze-thaw cycles.
What does latitude refer to?
The distance north and south of the equator.
Latitude is expressed in degrees and affects climate and weather patterns.
What does altitude refer to?
Height above sea level.
Altitude can influence temperature, vegetation, and weather conditions.
What action occurs in Ireland during the winter and for much of the year?
Freeze - thaw action
This process is significant in shaping the landscape through weathering.
What happens to water in the cracks of rocks during the day?
Water seeps into joints (cracks) in the rock
This infiltration is crucial for the freeze-thaw process.
What occurs at night in relation to the freeze-thaw action?
Ice freezes
The freezing of water at night contributes to the expansion process.
By how much can water expand when it freezes?
Up to 9%
This expansion exerts pressure on the surrounding rock.
What is the result of water freezing and thawing repeatedly over time?
The rock cracks and breaks off
This process leads to the formation of scree.
What type of debris is formed as a result of freeze-thaw action?
Scree
Scree consists of broken rock fragments that accumulate at the base of slopes.
What happens to the temperature that contributes to freeze-thaw action?
It drops below freezing point (0°C)
This drop initiates the freezing of water within the rock cracks.
Fill in the blank: Freeze-thaw action puts _______ on the rock.
Strain
The strain leads to the gradual breaking of the rock.
What happens to the rock pieces after they break off due to freeze-thaw action?
They roll down the mountainside and collect at the bottom of the slope
This accumulation of rock debris is characteristic of freeze-thaw weathering.
What is scree?
A collection of loose stones that form or cover a slope on a mountain.
Examples include Sugarloaf or Croagh Patrick.
What is exfoliation in weathering?
A process where rock layers peel off due to expansion, contraction, and cracking from repeated heating and cooling.
Often referred to as ‘Onion Peeling’.
In what type of climate does exfoliation primarily occur?
In areas with extremely high daytime temperatures and very low nighttime temperatures, such as deserts.
What is chemical weathering?
The process where rocks are broken down by chemical reactions.
List two types of chemical weathering.
- Carbonation
- Oxidation
