Processes of Denudation chapter 5 Geography

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Processes of Denudation chapter 5 Geography

Chemical weathering ;

A Karst region is a large area defined by limestone rock .

Carbonation is an example of chemical weathering that involves carbon dioxide and calcium carbonate.

Chemical weathering is the breaking down or dissolving of minerals in rocks caused by a chemical reaction .

Denudation :

Weathering is grouped into three main categories: mechanical, chemical and biological .

Erosion is the wearing down and transportation of materials across the surface of the earth.

The broken-down material may or may not be transported.

Weathering is the breaking down or dissolving of minarals and rocks across the surface of the Earth.

Denudation is the breaking down and carrying away of material over time caused by the processes of weathering and erosion .

Carbon dioxide

5. Limestone is a permeable. makes down continues to dissolve the limestone that is underground.

4. The acidic rainwater falls on the limestone landscape of the Burren and enters rivers and streams . Reacts with the calcium carbonate in limestone and forms calcium bicarbonate, which dissolves limestone rock over time. This dissolves rocks is washed away by flowing water.

3. When rains falls from clouds it absorbs more carbon dioxide from the atmosphere . this additional carbon dioxide turns the rainwater into a weak carbonic acid.

2. This carbon dioxide gather and is transported in clouds.

1. Carbon dioxide (CO2) gas is naturally present in the atmosphere. Factories, cars and homes also relese carbon dioxide into the air.

Surface features of a karts landscape.

Carbonation dissolves and weathers the joints and bending planes present in limestone pavement .This widens the joint and creates many surface features as it weakens and breaks down rock:

A swallow hole is a hole in the landscape were the rock has been dissolved. A swallow hole allows a river or stream to flow underground.

A Karren is a circular-shaped scoop that forms on the surface of a clint.

A clint is a slab of limestone separated by grikes.

A grike is a deep gap or groove between slabs of limestone.

The landscape that has evolved here is called limestone pavement, which is large slabs of limestone rock that are separated vertically by joints and horizontally by bedding planes.

the surface of the Burren tells the story carbonation over time.

Underground features of a karts landscape.

9. Futher down the landscape the stream may emerge on the surface again.

8. The stream that once entered through the swallow hole creates a new pathway out of the cave and it continues to flow underground.

7. Stalagmites and Stalacitites can often grow towards each other and eventually connect to form a pillar.

6. Some of the evaporated water sticks to the roof the cave and can drip back to the ground. Calcite is also left behind on the roof of the cave to form a stalactite, which is an inverted stalagmite that forms on the roof of a cave.

5. The process of evaporation leaves behind a tiny amount of the mineral calcite. Calcite builds up over time to form a stalagmite, which is a build-up rock on the floor of a cave.

4. As the temperature rises underground, the water present beings to evaporate.

2. This leads to the creation of a cave, which is a large underground area that is formed over time by carbonation.

2. These streams carve out a path and flow down through swallow .

1. Rainwater is carried in streams across the land scape of the Burren .

Mechanical weathering

The weathered rock collection at the base of a hill and is called screen.

4. Once the temperature rises again, the ice melts to water and the widened crack collection more water.

3. As the water turns to ice, it expands by 9 per cent of it's volume. This expanding widens the orginal crack in the rock, creating a larger crack.

2. At night temperature drops and causes the water to freeze.

Fig. 5.3 (a) Freeze-thaw action

Freeze-thaw action is a form of mechanical weathering that occurs in areas where the temperature regularly rises above and falls below freeze ( 0*C ).

Mechanical weathering, often referred to as physical weathering, is the breakdown of rock into smaller pleces by natural forces .

Biological weathering

Biological weathering is the breakdown of rock caused by plants and animal.