Deck 16- Impact of geology on the coastline

Question 1

What are igneous rocks?

Answer 1

Igneous rocks form from magma that cools and crystalises as it rises towards the surface, for example during volcanic eruptions

Question 2

What are sedimentary rocks?

Answer 2

Sedimentary rocks are formed when other rocks are broken down into pieces and are deposited into layers. Over time the layers become compacted and cemented forming a solid rock

Question 3

What are metamorphic rocks?

Answer 3

Metamorphic rocks form when rocks are buried at high pressures and temperatures which causes them to recrystalise

Question 4

Which two types of rocks are generally more resistant to erosion?

Answer 4

Igneous and metamorphic rocks are more resistant to erosion due to their crystalline structure.

Question 5

Why are sedimentary rocks less resistant to erosion?

Answer 5

They are tiny lines of weaknesses due how they form in layers, which make a focal point for erosional processes

Question 6

State three examples of igneous rocks.

Answer 6

Granite, basalt, pumice

Question 7

State three examples of metamorphic rocks.

Answer 7

Slate, schist, quartzite

Question 8

State three examples of sedimentary rocks.

Answer 8

Sandstone, limestone, chalk

Question 9

What is a discordant coastline?

Answer 9

A discordant coastline is where the type of rock runs perpendicular (at a right angle) to the coastline.

Question 10

What is a concordant coastline?

Answer 10

A concordant coastline is where the type of rock runs parallel to the coast. The limestone at forms a concordant coastline on the south Dorset coastline.

Question 11

What is an example of an area that has both discordant and concordant coastlines?

Answer 11

Swanage, Dorset

Question 12

What sort of landforms form along a discordant coastline?

Answer 12

The series of headland and bays made by alternating bands of rocks is characteristic of a discordant coastline.

Question 13

How do headlands and bays form at discordant coastlines?

Stretch: Include the specific names of locations and rock types at Swanage Bay

Answer 13

The less resistant bands of rocks (e.g. mudstones in Swanage Bay) erode at a faster rate than the more resistant rocks on either side (e.g. chalk at Ballard Point and limestone Durlston Head) leading to the formation of headlands and bays.

Question 14

What is wave refraction and how does it influence the formation of headlands and bays?

Answer 14

Wave refraction is the bending of waves as they approach an uneven coastline, causing the wave energy to concentrate on protruding headlands and disperse in the recessed bays, leading to increased erosion at headlands and deposition in bays, thus shaping the coastline into a pattern of headlands and bays.

Question 15

What landforms are characteristic of a concordant coastline?

Answer 15

Concordant coastlines are usually rocky coastlines that become a focus for erosion and form features such as wave cut platforms, caves, arches, stacks and stumps.

Question 16

How can a headland and bay form at a concordant coastline?

Stretch: Include an example of where this has happened and the rock types present here.

Answer 16

At Lulworth Cove the sea has broken through the limestone due to a pre-existing weakness in the rock.

Once the sea had eroded past the limestone it was much easier to erode the poorly consolidated mudstone so this eroded much faster than the remaining limestone forming a wide cove with a narrow breach.

When the sea reached the consolidated chalk the rate of erosion slowed as the chalk is more resistant than the mudstone. The cove is becoming wider as the sea continues to erode the mudstone at the fastest rate.

Question 17

What is a Dalmatian coastline?

Answer 17

Dalmatian coastlines are a specific type of concordant coastline that form when some parts of landscapes are flooded due to sea level rise. Prior to the sea level rising there would have been a series of ridges and valleys running parallel to each other. As the sea level rose the valleys were flooded leaving the ridges remaining above the water.

Question 18

State an example where a Dalmatian coastline has formed.

Answer 18

Croatia

Question 19

What is a Haff coastline?

Answer 19

Haff type coastlines are a type of concordant coastline. They are a depositional concordant coastline where unconsolidated sediment e.g. sand and shingle have been deposited in structures parallel to the coastline. The sediment has been reworked by waves since it was deposited by meltwaters at the end of the Last Glacial Maximum,.

Question 20

State an example of a Haff coastline.

Answer 20

Frisian Islands in the North Sea, Netherlands/Germany and Vistula Lagoon in the Baltic Sea, Poland