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
What occurs during carbonation?
Carbon dioxide weathers rocks like limestone and chalk through the formation of carbonic acid.
Rainwater mixes with CO2 to create carbonic acid.
What is the primary component of limestone that is affected by carbonation?
Calcium carbonate.
How much calcium carbonate can limestone contain?
Up to 95%.
What is the effect of carbonic acid on calcium carbonate?
Carbonic acid changes calcium carbonate into soluble calcium bicarbonate.
In which type of water is the weathering process by carbonic acid more effective?
Cold water.
What gas does cold water hold more of, enhancing the weathering process?
Carbon dioxide (CO2).
What are the steps in the weathering process involving carbonic acid?
CO2 + H2O = H2CO3 (carbon dioxide + water = carbonic acid).
Fill in the blank: Carbonic acid dissolves calcium carbonate into _______.
calcium bicarbonate.
True or False: The process of carbonic acid changing calcium carbonate is faster in warm water.
False.
What is weathering?
The process of breaking down rocks over time.
Weathering can be caused by physical, chemical, or biological processes.
What is oxidation?
A chemical process that involves the formation of rust, weakening and breaking down rocks.
Oxidation is a common form of chemical weathering.
What is lichen?
An organism made of a fungus and an alga that causes biological weathering.
Lichen can break down rocks through chemical processes.
What is a karst landscape?
An area of exposed limestone formed by glaciation, featuring unique geological formations due to carbonation.
Karst landscapes often include caves, swallowholes, and other distinctive features.
List two surface features of karst landscapes.
- Clints
- Grikes
List two subsurface features of karst landscapes.
- Stalagmites
- Stalactites
What are clints and grikes?
Features of limestone pavement where clints are the flat areas and grikes are the fissures between them.
They are formed through the weathering of limestone.
What is a stalagmite?
A mineral formation that rises from the floor of a cave, formed by the dripping of mineral-rich water.
Stalagmites grow upwards, while stalactites hang from the ceiling.
What is a swallow hole?
A feature in a karst landscape where surface water disappears into the ground.
Swallow holes can lead to underground rivers.
What is the significance of carbonation in karst landscapes?
It is the primary process that leads to the formation of karst features.
Carbonation occurs when carbon dioxide dissolves in water, forming carbonic acid that erodes limestone.
True or False: The Burren in Co. Clare is an example of a karst landscape.
True
Fill in the blank: _______ is a process that causes biological weathering.
Lichen
What is a karst landscape?
A type of landscape characterized by features formed from the dissolution of soluble rocks such as limestone.
What is a swallow hole?
A feature that forms when a river flows into a grike, which carbonation and erosion deepen, causing the river to disappear underground.
Fill in the blank: A swallow hole forms when a river flows into a _______.
grike
What geological process deepens a swallow hole?
Carbonation and erosion.
What is one economic advantage of tourism in the Burren?
Creation of many direct and indirect jobs in hotels, cafes, and eco-tourism
The Burren is expected to attract 800,000 visitors in 2024.
What environmental measure is taken to protect the Burren?
Strict planning laws within the Geo Park
These laws aim to prevent overdevelopment and protect the natural beauty of the area.
During which months is tourism in the Burren most active?
April to September
Most tourist visits occur during these months, leading to seasonal job opportunities.
What social issue has arisen due to tourism in the Burren?
Increased house prices due to wealthy people buying holiday homes
This trend makes it too expensive for locals to buy homes, forcing them to move.
What is a major environmental concern related to tourism at popular attractions like the Cliffs of Moher?
Traffic congestion and CO2 emissions lowering air quality
Increased vehicle use contributes to these environmental issues.
