2B.2b

Question 1

What does lithology involve

Answer 1

strata, bedding planes, joints or cracks, folds, faults, dips

Question 2

What does geological structure have an impact on

Answer 2

coastal morphology, erosion rates, the formation of cliff profiles and the occurrence of micro-features, e.g. caves

Question 3

Define cliff profiles

Question 4

Define coastal morphology

Answer 4

shape and form of coastal landscapes and their features

Question 5

Define jointing

Answer 5

Joints are fractures in rocks created without displacement.

Question 6

Define faulting
also state their scale, effects on rate of erosion and how faulting occurs

Answer 6

• major fractures in rock created by tectonic forces, with displacement of rocks either side of the fault line.
• often large scale, extending many kilometres.
• significantly increases rate of erosion, since zones of faulted rock are much more easily eroded.
• Huge forces are involved in faulting and displacing them. Because of this, either side of the fault line, rocks are often heavily fractured and broken, which is easily exploited by marine erosion

Question 7

Joints vs Faults

Answer 7

If rocks on one side of the break shift relative to rocks on the other side, then the fracture is a fault. If there is no movement of one side relative to the other, and if there are many other fractures with the same orientation, then the fractures are called joints.

Question 8

What are folds

Answer 8

Folds are bends in rocks. They are produced by sedimentary rock layers being squeezed by tectonic forces. The two main types are anticlines and synclines.

Question 9

Define dipping

Answer 9

Dip is the angle of inclination of the rock strata from the horizontal. It’s a tectonic feature. Sedimentary rocks are deposited horizontally, but can be tilted by folding and faulting by tectonic forces

Question 10

Define cliff profile

Answer 10

the height and angle of a cliff face, plus its features such as wave-cut notches or changes in slope angle

Question 11

Define cliff profile

Answer 11

the height and angle of a cliff face, plus its features such as wave-cut notches or changes in slope angle

Question 12

What is horizontal dipping like

Answer 12

produces a vertical, or near-vertical profile, with notches reflecting weathering and small scale mass movement of strata that are jointed or more easily eroded

Question 13

Describe High angle of seaward dip

Answer 13

(>45) produces a sloping, low-angled profile with one rock layer facing the sea; vulnerable to rock slides down the dip slope when uppermost strata are attacked by sub-aerial processes. The profile slopes corresponding to that of strata dip. Bedding planes between strata are weakly bonded and readily loosened by weathering

Question 14

Describe Low angle of seaward dip

Answer 14

(<45) produces a steep profile, that may even exceed 90 degrees, creating areas of overhanging rock; very vulnerable to rock falls. Frequent small-scale mass movement of material weathered from cliff face. Major cliff collapse when undercutting by marine erosion makes overhang unsustainable

Question 15

describe Landward dipping strata

Answer 15

produces steep profiles on 70-80’ as downslope gravitational force pulls loosened blocks into place. Very stable profile with few rock falls

Question 16

Ref to p50 for dipping diagrams

Answer 16

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