Denudation Flashcards
(29 cards)
What is weathering
Weathering is the break down of rocks from exposure to weather
What is erosion
Erosion is the breakdown of rocks and removal of particles
What does erosion remove
Scree/particles
What are the two types of weathering
Mechanical and chemical
How is erosion caused
Caused by moving air (wind) moving water (lake, sea) moving ice (glacier)
What does mechanical weathering do?
Breaks the rock into smaller pieces
Name one type of mechanical weathering
Freeze thaw action
Where does freeze thaw action occur
High in the mountains where there is lots of rain and the tempature rises and drops below 0 degrees often
Stage one of frees thaw action
During the day water seeps into the cracks in the rocks
Stage two freeze thaw action
At night tempature so fall below freezing point the water in the cracks freezes and expands (10%) putting pressure on the rock
Stage three freeze thaw action
Over time this process continues to occur weakening the rock and eventually forcing a piece to break off. The broken rock is known as scree
What does chemical weathering do
Dissolves rock
What is one example of chemical weathering
Carbonation
Where does carbonation occur
Limestone landscapes
How does carbonation occur
Rainwater mixes with carbon dioxide in the atmosphere forming a weak carbonic acid
What does the weak acid carbonation react with
Calcium carbonate in the limestone
What are areas where limestone is exposed to weather known as
Karst landscapes
State an example of a karst landscape
Burden county Clare
Limestone pavement
Series of clints, grikes and joints
Clint
Block of limestone between grikes
Grikes
Narrow gaps between blacks of limestone formed by rainwater and acid
Swallow hole
Disappearing river hoes underground when reaches limestone pavement
Pollnagollum
Swallow hole in the burren
Caverns
Enlarged caves
