6 Weathering Processes and Landforms Flashcards
What is denudation
Collective name for weathering and erosion of rocks
What is erosion
When rocks are broken down and remvoed by stuff like wind,water,ice.
Another name for mechanical weathering
Physical weathering
What is mechanicaal/physical weathering
Occurs in areas of extreme temps
Rock is physically broken down into smaller pieces
Chemical composition is not altered
What is chemical weathering
Wet and humid conditions
Rocks decay or dissolve as their chemical composition is altered
What is biological weathering
Breakdown of rock by the actions of plants or animals
Factors affecting rate of weathering
-Rock type (Soft/hard minerals)
-Surface area
-Climate
-Vegetation (Vegetation shields)
-Human activity (Pollution=acid rain)
4 Mechanical/Physical weathering processes
1.Freeze-Thaw Action
2.Exfoliation
3.Salt crystallisation
4.Pressure Release
2 Other names for freeze-thaw action
-Frost action
-Frost shattering
Another name for scree
Talus
Freeze-Thaw Action location example
Croagh Patrick, Co.Mayo
Exfoliation example
Sonoran Desert
How much does the ice expand in joints during freeze-thaw action
Approx 9%
What is scree/talus
Sharp angular pieces of rock that break away from rock and move down slope due to gravity in Freeze-THaw action
Define dirunal temp range
The difference between the highest and lowest temp in a 24hr period. For exfoliation to occur there must be a large dirunal temp range
What is exfoliation sometimes referred to as
Onion peeling
How does mineral content affect exfoliation
Rocks expand at different rates depending on mineral content
Salt crystalliation example
California Coastline
Pressure release example
Granite in wicklow mnts
Whats another word for salt crystallisation
Haloclasty
What is pressure release also known as
Unloading/sheeting
How is salt crystallisation identified
Honeucomb pattern on sea walls constructed off granite, sandstone, limestone
4 Chemiaccl Weathering processes
1.Carbonation
2.Oxidation
3.Hydration
4.Hydrolysis
Carbonation example
Burren, Co.Clare
Brief summary of carbonation
Rain falls through sky
Absorbs carbon dioxide
forms a weak carbonic acid
Hits limestone rock + reacts with the calcium carbonate in the rock
Soluble calcium bicarbonate is formed
Oxidation example
Colorado Plateau
What is oxidation commonly referred to as
Rusting
Hydration
Rocks that dont contain water such as gypsumor shale, absorb rain water, expand and become soft, and break apart
Hydrolysis example
Cleopatras Needle New York
What is hydrolysis
Hydrogen in water reacts with minerals in rock creating a chemical reaction. Forms clay
What is biological weathering
Animals/plant roots can widen the joints between rocks allowing water to penetrate further into the rocck
2 Distinctive Irish Landscapes formed by Weathering
1.Granite Landscapes
2.Karst Landscapes
Granite landscape example
Three Rock Mountain
Leinster Batholith
What is a Tor
A large block of rock that has been weathered more slowly than its surroundings
Karst landscape surface features
1.Limestone pavement
2.Swallow holes
3.Disappearing stream
4.Dry Valleys
5.Dolines
6.Turloughs
