Geology And The Coast

Question 1

What is coastal morphology?

Answer 1

The shape and form of coastal landscapes and their features.

Relates to the underlying geology, rock type and the geological structure.

Question 2

What is lithology?

Answer 2

The physical characteristics of particular rocks.

Question 3

What are the characteristics in lithology?

Answer 3

Strata 
Bedding planes 
Joints 
Folds 
Faults 
Dip

Question 4

What are strata?

Answer 4

Layers of rock

Question 5

What are bedding planes?

Answer 5

Horizontal cracks - natural breaks in the strata, caused by gaps in time during periods of rock formation.

Question 6

What are joints?

Answer 6

Vertical cracks - these are fractures, caused either by contraction as sediments dry out, or by earth movements during uplift.

Question 7

What are folds?

Answer 7

Formed by pressure during tectonic activity, which makes rocks buckle and crumple (e.g. Lulworth Crumple)

Question 8

What are faults?

Answer 8

Formed when the stress or pressure to which a rock is subjected, exceeds its internal strength (causing it to fracture).

The faults then slip or move along fault planes.

Question 9

What does dip mean?

Answer 9

Refers to the angle at which rock strata lie (horizontally, vertically, dipping towards the sea, or inland).

Question 10

What does the relief mean?

Answer 10

Height and slope of land - also affected by geology and geological structure

Question 11

What does geology and lithology affect?

Answer 11

The speed at which a coast erodes/recedes.

Question 12

What are different types of rock?

Answer 12

Igneous
Sedimentary
Metamorphic
Unconsolidated

Question 13

What are igneous rocks?

Answer 13

Granite - crystalline, resistant and impermeable

Question 14

What are sedimentary rocks?

Answer 14

Limestone, chalk, sandstone and shale.

Formed in strata.
Jointed sedimentary rocks (sandstone and limestone) are permeable.
Other sedimentary rocks (chalk) have air spaces between the particles - making them porous.
Shale is fine grained and compacted - making it impermeable

Question 15

What are metamorphic rocks?

Answer 15

Marble - very hard, impermeable and resistant

Question 16

What are unconsolidated materials?

Answer 16

Loose, such as the boulder clay of Holderness.

They are not cemented together in any way and are easily eroded.

Question 17

What affects the rate of erosion or recession?

Answer 17

Geology
Lithology
Weathering
Mass movement

Question 18

What are concordant coasts?

Answer 18

This is where bands of more-resistant and less-resistant rock run parallel to the coast

Question 19

What are Dalmatian coasts?

Answer 19

A type of concordant coastline.

They have formed as a result of a rise in sea level. Valleys and ridges run parallel to each other.
When the valleys flooded because of sea level rise, the tops of the ridges remained above the surface of the sea - as a series of offshore islands that run parallel to the coast.

Question 20

What are haff coasts?

Answer 20

Also consist of concordant features - long spits of sand and lagoons - aligned parallel to the coast.

Question 21

What are disconcordant coasts?

Answer 21

The geology alternates between bands of more-resistant and less-resistant rock, which run at right angles to the coast.

Question 22

What are headlands and bays?

Answer 22

Headlands jut out into the sea, and bays lye between them

Question 23

How do headlands and bays form?

Answer 23

When rocks of different strengths are exposed at the coast.

More resistant rocks, such as chalk and limestone tend to form headlands, whilst weaker rocks, such as shale and clays, are eroded to form bays.

Question 24

How do headlands and bays affect incoming waves?

Answer 24

Headlands - force the incoming waves to refract or bend - concentrating their energy at the headlands.
This increases the waves erosive power, which leads to a steepening of the cliffs and their eventual erosion into arches and stacks

When waves enter a bay, their energy is dissipated (spread out) and reduced. This leads to the deposition of sediment (sand or shingle) - forming a beach

Question 25

What increases a waves erosive power at headlands?

Answer 25

The depth of the water decreases…
This causes the waves to get higher and steeper.
Their velocity also reduces
They become closer together

Question 26

What decreases a waves erosive power at bays?

Answer 26

Water is deeper.
So they don’t lose their velocity as rapidly.
Lower and less steep than those off the headland.
This allows for deposition rather than erosion