3.1.3
Lithology & Vegetation
Lithology and Coastal Recession
Lithology and Coastal Recession
Lithology plays an important role in the rate of coastal recession.
Bedrock lithology
Bedrock lithology
- When Geographers talk about the physical properties of different rocks, this is known as bedrock lithology.
- The existence of sedimentary, igneous and metamorphic rocks affects the rate of recession along a coastline.
Igneous rocks
Igneous rocks
- Igneous rocks, such as Basalt and Granite, form from the crystallisation of magma. They are more resistant to erosion and weathering.
- This is because igneous rocks contain crystals which increase the strength of the rocks and reduce the number of lines of weaknesses that would be exploited by physical processes.
- Igneous rocks can either be intrusive (formed from magma inside the Earth) or extrusive (formed when magma escapes through vents on the Earth’s surface).
- The average rate of erosion of igneous rocks is 0.1-0.5 cm per year.
Sedimentary rocks
Sedimentary rocks
- Sedimentary rocks, such as Limestone and Sandstone, form from the build-up, compacting and hardening of sediments into layers over time by lithification.
- Sedimentary rocks that have been formed in a shorter geological time scale tend to be more susceptible to erosion and weathering and erode at a faster rate compared with those formed over a longer geological time.
- E.g. limestone and chalk.
- The average rate of erosion of sedimentary rocks is 2-6 cm per year.
Metamorphic rock
Metamorphic rock
- Metamorphic rocks, such as slate and marble, are formed from the change in the structure of sedimentary and igneous rocks, caused by variations in heat and pressure.
- The process of change is referred to as the rocks having been metamorphosed.
- Marble is an example of a metamorphic rock that has been formed from the changing structure of limestone caused by the re-crystallisation of calcite.
- Metamorphic rocks are resistant to erosion.
Vegetation
Vegetation
Vegetation is important in supporting the development of sandy coastlines and so plays an important role in the rate of coastal recession.
Sand dunes
Sand dunes
- Sand dunes need a continuous supply of sand, powerful winds to transport sand and obstacles to trap the sand, like plants.
- A typical sand dune transect goes from the mobile dunes nearest the sea (embryo, fore and yellow) to the fixed dunes nearest the backshore (grey dunes and dune slack).
- Sand dunes contain two types of plants:
- Xerophytes, which can withstand periods of dry weather.
- Halophytes, plants that can withstand high concentrations of salt from seawater.
Vegetation succession on dunes
Vegetation succession on dunes
- Typical plants that colonise embryo and foredunes are sea rocket and sea crouch. These plants have deep roots and can tolerate high concentrations of salt.
- Yellow dunes tend to be colonised by marram grass. These plants also have long deep roots and are salt tolerant.
- Heathers are commonly found in grey dunes because of the higher rates of humus.
1Tectonic Processes & Hazards
1.1Tectonic Processes & Hazards
1.2Natural Disasters
1.3Natural Disaster Case Studies
1.4Trends & Patterns
2Option 2A: Glaciated Landscapes & Change
2.1Glaciated Landscapes Over Time
2.2Periglacial Landscapes
2.3Glacial Processes
2.4Glacial Landforms
3Option 2B: Coastal Landscapes & Change
3.1Coastal Landscapes
3.2Coastal Erosion & Deposition
3.3Coastal Risks
4Globalisation
4.1Globalisation
4.2Negatives of Globalisation
4.3Global Shift
4.5Culture
4.6Measuring Development
5Option 4A: Regenerating Places
5.1Types of Economies
5.2Function of Places
5.3Regeneration
5.4Regeneration Case Studies
6Option 4B: Diverse Places
6.1Population Structure
6.2Past & Present Connections
6.3Urban & Rural Spaces
6.4Diversity
6.5Urban & Rural Case Studies
6.6Case Study - Tower Hamlets
6.7Case Study - Sturton-le-Steeple
7The Water Cycle & Water Insecurity (A2 only)
7.1Hydrological Processes Global to Local
7.2Influences on the Water Cycle
7.3Water Insecurity
8The Carbon Cycle & Energy Security (A2 only)
8.1The Carbon Cycle
8.2Energy Consumption
8.3Alternative Energy
8.4Growing Demand for Resources
9Superpowers (A2 only)
9.1Superpowers
9.2Hard & Soft Power
9.2.1Hard & Soft Power
9.2.2Emerging Powers - China Rivalry
9.2.3Emerging Powers - Chinese Sources of Power
9.2.4Emerging Powers - Brazil
9.2.5Emerging Powers - Russia
9.2.6Emerging Powers - India
9.2.7Theories of Development
9.2.8Power Case Studies: Chinese One Belt One Road
9.2.9Power Case Studies: Pakistan Nuclear Arms
9.2.10Power Case Studies: OPEC
9.3IGOs, TNCs & Alliances
10Option 8A: Health & Human Rights (A2 only)
10.1Human Development
10.2Role of Governments & IGOs
10.3Human Rights
10.4Interventions
11Option 8B: Migration & Identity (A2 only)
11.1Globalisation & Migration
11.2Consequences of Migration
11.3Nation States
11.4Responses to Global Migration
Jump to other topics
1Tectonic Processes & Hazards
1.1Tectonic Processes & Hazards
1.2Natural Disasters
1.3Natural Disaster Case Studies
1.4Trends & Patterns
2Option 2A: Glaciated Landscapes & Change
2.1Glaciated Landscapes Over Time
2.2Periglacial Landscapes
2.3Glacial Processes
2.4Glacial Landforms
3Option 2B: Coastal Landscapes & Change
3.1Coastal Landscapes
3.2Coastal Erosion & Deposition
3.3Coastal Risks
4Globalisation
4.1Globalisation
4.2Negatives of Globalisation
4.3Global Shift
4.5Culture
4.6Measuring Development
5Option 4A: Regenerating Places
5.1Types of Economies
5.2Function of Places
5.3Regeneration
5.4Regeneration Case Studies
6Option 4B: Diverse Places
6.1Population Structure
6.2Past & Present Connections
6.3Urban & Rural Spaces
6.4Diversity
6.5Urban & Rural Case Studies
6.6Case Study - Tower Hamlets
6.7Case Study - Sturton-le-Steeple
7The Water Cycle & Water Insecurity (A2 only)
7.1Hydrological Processes Global to Local
7.2Influences on the Water Cycle
7.3Water Insecurity
8The Carbon Cycle & Energy Security (A2 only)
8.1The Carbon Cycle
8.2Energy Consumption
8.3Alternative Energy
8.4Growing Demand for Resources
9Superpowers (A2 only)
9.1Superpowers
9.2Hard & Soft Power
9.2.1Hard & Soft Power
9.2.2Emerging Powers - China Rivalry
9.2.3Emerging Powers - Chinese Sources of Power
9.2.4Emerging Powers - Brazil
9.2.5Emerging Powers - Russia
9.2.6Emerging Powers - India
9.2.7Theories of Development
9.2.8Power Case Studies: Chinese One Belt One Road
9.2.9Power Case Studies: Pakistan Nuclear Arms
9.2.10Power Case Studies: OPEC
9.3IGOs, TNCs & Alliances
10Option 8A: Health & Human Rights (A2 only)
10.1Human Development
10.2Role of Governments & IGOs
10.3Human Rights
10.4Interventions
11Option 8B: Migration & Identity (A2 only)
11.1Globalisation & Migration
11.2Consequences of Migration
11.3Nation States
11.4Responses to Global Migration
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