Weatheirng Flashcards
What is denudation?
Denudation is the process of lowering earths land surface through weathering and erosion reducing elevation and relief
What is relief?
Relief refers to the difference in height of land on the earths surface, and includes mountains,valleys,hills and plains
What is weathering?
Weathering is the break down of rocks, soils and materials through exposure to the weather (rain,frost,ice,snow,wind) and organisms
What are the 3 categories of weathering?
Mechanical (physical) chemical, biological
What are the types of mechanical weathering?
Free thaw action (frost action), exfoliation (onion peeling)
what is free thaw action?
Free thaw action occurs in areas where temperatures regularly change between freezing and thawing. Occurs in areas of high altitude and high latitude
What is latitude?
The distance north and south of the equator
What is altitude?
How high something is above sea level
When does free thaw action occur in Ireland?
It occurs during winter and for much of the year in mountain ranges
What happens by day during free thaw action?
The water seeps through the cracks in the rock
What happens at night during free thaw action?
The temapture drops below freezing point. The water freezes and expands. This makes the cracks bigger and puts strain on the rock
What happens over time during freeze thaw action?
After reapted freezing and thawing of the water over many years the rock splits. Sharp jagged pieces, called scree break off. The roll down the mountainsides and collect in piles at the bottom of the slope
What is exfoliation and where does it happen?
Exfoliation occur where rock layers peel off due to reapted heating and cooling, causing expansion, contraction and eventually cracking. It happens in areas where temperatures are extremely high during the day and very low at night e.g. deserts
What is chemical weathering?
Chemical weathering is when rock is broken down by chemical reactions e.g. carbonation and oxidation
When does carbonation occur?
.Carbonation occurs when carbon dioxide weathers rocks like limestone and chalk.
.rainwater mixes with CO2 to create carbonic acid which dissolves calcium carbonate. Limestone can contain up to 95% calcium carbonate.
.the carbonic acid changes calcium carbonate into soluble calcium bicarbonate. This process is slower but more effective in cold water, which holds more CO2
. The steps are CO2+H2O= H2CO3 (carbon dioxide+water=carbonic acid)
.carbonic acid dissolves calcium carbonate into calcium bicarbonate
