Weathering and erosion

Weathering

The breakdown of rocks exposed to the weather.

Erosion

The breakdown and removal of rock by ice, water or wind.

Mechanical Weathering

The physical breaking down of rocks and material.

Freeze-thaw action

Freeze-thaw action is a type of mechanical weathering.

What do you need in order for freeze-thaw action to work?

You need precipitation, upland areas and where the temperature fluctuates above/below freezing point.

Name the steps of freeze-thaw action.

1. Water seeps in the cracks of the rock

2. Temperatures fall below freezing point and the water expands by 9%

3. The process repeats over time, and the rock breaks off

What is the broken off rock called?

Scree

Chemical Weathering

The breakdown of rocks through chemical reactions.

Carbonation

Carbonation is a type of chemical weathering.

Name the steps of carbonation.

1. Carbon dioxide mixes with rainwater to form a weak carbonic acid.

2. Limestone contains calcium carbonate and is permeable.

3. When the carbonic acid reacts with the calcium carbonate it dissolves.

Karst Region

An area of limestone landscape where the rock is exposed to weathering.

Clint

The blocks of limestone that stay after carbonation widens the cracks in karst regions.

Grike

The gaps formed between the clints in a limestone pavement due to carbonation.

Stalagmite

Forms when calcite deposits to the ground over time when water evaporates.

Stalactite

Forms from calcite deposits on the ceiling of a cave when water containing dissolved calcium carbonate drips down.

How is a swallow hole formed?

1. A river flows over an exposed limestone surface.

2. Carbonation dissolves the limestone.

3. The joints and bedding planes widen and open.

4. The river disappears and flows underground.

5. Hydraulic action widens the joints further.

Burren

A limestone area in Co. Clare with distinct karst features.