Define rock structure.
The way the rocks are disposed or geologically arranged.
The 'make-up' of each individual rock type.
What do the combined impacts of structure and lithology affect? 3 things.
- Coastline in plan
- Coastline in profile - cliffs/wave cut platforms
- Distribution of micro-features - caves/arches/etc
Which rock type are more resistant to erosion?
- Igneous and metamorphic
- Harder so more resistant
- Form high cliffs in NW Britain
Which rock types are less resistant to erosion?
- Sedimentary rocks, unconsolidated sands, clays or tertiary age, deposits of glaical boulder clay/gravels
- Softer to less resistant
- S+E Britain coastlines
How does permeability affect coastal rate of erosion?
- Surface water seeps through cliffs, increasing its resistance to subaerial processes
What factors affect coastal landforms? 8 factors.
- Geomorphic factors
- Marine factors
- Subaerial factors
- Human factors
- Biotic factors
- Climatic factors
What are concordant coasts?
Direction of coast lies parallel to shore
What are discordant coasts?
Direction of coast lies perpendicular to shore
What is zonation?
- The change in species of plants and animals along an environmental gradient.
- If you walk up a beach away from the sea, the plants and animals will change as you get further away
- Spatial change in species.
What is succession?
- A change in the species of a particular area over time.
- If you set up a tent in the middle of a field that isn’t managed or influenced by humans in any way, and stay in it for 50 years, when you step outside you will be surrounded by bushes and small trees. The plants and the animals in the soil will have changed.
- Temporal change.
Why doesn’t one species just take
over the whole beach?
Different parts of the beach have very different characteristics.
Describe the initial conditions of a sand dune.
- Conditions are harsh: little water/nutrients
- Sand is shifting so difficult for plant roots to get a hold.
- Marram grass develops because it is well adapted to harsh conditions
Describe the conditions of sand dune after Marram grass develops.
- Marram grass begins to change the conditions
- It traps sand -> more stable, allowing other plant roots to get a hold.
- Some Marram plants die -> break down -> organic matter is added to the sand
- Provides a source of nutrients + helps retain water in the sand
- Other plants, which are better adapted to these changed conditions thrive
How does succession occur on a sand dune?
- Eventually conditions change so much that new species out-compete Marram
- Succession has occurred and continues to occur as conditions continue to change