Lithology & Geology

Define Sedimentary Rock

Made up of small particles of sand/rock, which have been transported by the wind, rivers and ice and are usually deposited on lake or seabed

Define Igneous rocks

Rocks that form when magma from mantle cools down and hardens

What rocks are Sedimentary ?

Chalk ,sandstone and limestone

What rocks are Igneous ?

Granite

How do we classify rocks ?

Unconsolidated - Weak
Sedimentary - Soft
Igneous - Hard
Metaphoric - Very hard

Define unconsolidated rocks ?

Rocks with very weak cementation , meaning they are more susceptible to deformation or erosion than lithified sedimentary rocks.

What 3 factors impacts the geological structure of a coastline ?

Strata, Faulting and deformation

What coastal landforms are formed as a result of limestone ?

very resistant to erosion leading to headlands like Duriston head being formed.

What coastal landforms are formed as a result of chalk ?

less resistant to erosion which led to the formation of Studland and Swanage bay being formed

What coastal landforms are formed as a result of clay ?

Has no resistant to erosion forming headlands and cliffs near coasts

Define Strata

the different layers of rock within an area and how they relate to each other.

Define Faulting

the presence of major fractures that have moved rocks from their original positions.

Define Deformation

the degree to which rock units have been deformed (tilted or folded) by tectonic activity.

What is a concordant coastline ?

Where there is one type of rock that runs parallel to the coastline (pacific coasts)

What is a discordant coastline ?

When different rock strata runs Perpendicular to the coastline. (Atlantic coasts)

What features are found at a concordant coastline ?

Cove , Dalmatian coasts and Haff coasts

What features are found at a discordant coastline ?

headlands , bays, wave refractions and CAStS

How was Lulworth Cove formed?

1. Waves eroded a weak band of Wealden clay at the coast.
3. Limestone behind it slowed erosion but was eventually breached.
3. Clay behind was eroded, forming the circular cove.
4. Harder chalk and limestone rocks on the sides limit its expansion.

How is a Dalmatian Coastline formed ?

1. Tectonic uplifts ,creating parallel ridges and valleys.
2. Rising sea levels flood the valleys between the ridges.
3. The higher ridges remain above water, while the valleys become narrow islands.

What causes sea level rise ?

Melting Ice caps and glaciers, adding more water to the oceans.
Warmer Water Expands: When ocean water heats up, it expands and takes up more space, causing sea levels to rise.

What causes Tectonic uplift ?

Plate Collision- Convergent
Subduction- Convergent
Rifting- Divergent

How is a Haff coastline formed?

Rising Sea Levels: Sea levels rise and flood low-lying coastal areas, creating shallow seas along the shore.
Formation of Long Sandbars: Long sandbars or spits are created by waves and currents depositing sand and gravel parallel to the coastline.
Enclosed Shallow Areas: These sandbars trap water behind them, forming shallow lagoons or bays.

Give an example of where a Haff coastline is found

They are found on the southern fringes of the Baltic sea

Explain how wave refraction works ?

1. In deep water, wave crests are parallel to each other.
2.As waves approach the shore, they slow down in shallow water near headlands, causing the waves to get Stronger and Taller.
3.In bays, waves curve to fill the space, and their height and strength decreases.
4. Wave refraction causes waves to bend, concentrating energy on headlands increasing erosion and spreading it out in bays causing less erosion.

How does wave refraction affect erosion along a coastline with headlands and bays?

Wave refraction erodes headlands more and erodes bays less.

What type of landform dominates discordant coastline ?

Headlands and bays

How was Studland bay formed ?

The rock beds consist of unconsolidated sands and clays. These are less resistant to erosion and, where exposed to the sea at Studland, have formed a large bay as a result.