Coasts - Theme 2 - GEOLOGY

Question 1

What are the two sub sections of geology

Answer 1

• Lithology

- Structure

Question 2

What is lithology

Answer 2

• The way rocks are made up
• resistant?
• permiability
• chemical form

Question 3

What is Structure

Answer 3

-The way rocks are disposed

Question 4

What are the three rock types

Answer 4

• Igneous
• sedimentary
• metamorphic

Question 5

How are igneous rocks formed

Answer 5

• Rocks are pushed deep down into the earth
• They melt and become molten (magma)
• When errupted from volcanos they become lava
• When they cool they become igneous
• Igneous rocks have CRTYSTALS
• because they cool quickly (earth surface is cool) they have SMALL crystals
• Igneous rocks in the earth have larger crystalls because it takes longer to cool

Question 6

How are sedimentary rocks formed

Answer 6

• Sediment that is compacted under pressure to form a rock
• They are made up of grains
• Grains can be ANDULAR or GROUNDED
• They create pores
• IF PORES CONNECT THEY ARE PERMIABLE

Question 7

How are metamorphic rocks formed

Answer 7

• Rocks that change over time
• Under pressure and heat the grains and minerals change
• This is called METAMORPHISM
• Metamorphic rocks are crystilline
• THEY HAVE LAYERS
• two factors effect the type of rock
• type of rock at START and the AMOUNT of heat and pressure

Question 8

What are examples of igneous rocks

Answer 8

• basalt
• granite
• obsidian

Question 9

What are examples of sedimentary rocks

Answer 9

• limestone

- sandstone

Question 10

What are examples of metamorphic rocks

Answer 10

• marble
• slate
• gneiss

Question 11

How does lithology effect erosion rates

Answer 11

• Resistance
• Permeability
• Faults or bedding planes
• Chemical composition

Question 12

How does resistance effect erosion rates

Answer 12

• igneous and metamorphic rocks are hard
• harder to erode
• sedimentary rocks are easier to erode

Question 13

How does permiability effect erosion rates

Answer 13

• more permeable means there are cracks and joints
• vunurable to salt crystilisation hyrualic action freeze thaw
• CHALK IS AN EXCEPTION AND GETS STRONGER

Question 14

How does the physical make up of rock effect erosion rates

Answer 14

-more bedding planes and faults easier to erode

Question 15

How does chemical composition effect erosion rates

Answer 15

• if chemically inert then slow
• ferrous - oxidation
• CaCO3 - carbonation
• Saltwater causes rocks like basalt to weather 14 times faster

Question 16

How does structure and arrangement change erosian rates

Answer 16

-the strata in the rock deceide how organised the planes are and therefore erosion rates

Question 17

How does horizontal strata effect erosion rates

Answer 17

• resist the erosion

- produce tall cliffs

Question 18

How does vertical strata effect erosion rates

Answer 18

• weathering can lead to the rock becoming unstable

- erodes fast

Question 19

How does seaward dip strata effect erosion rates

Answer 19

• leads to sheets falling into the sea

- only needs one part of the strata to erode then whole sheet is eroded

Question 20

How does inland dip strate effect erosion rates

Answer 20

• more resistant to erosion and produces steep cliffs

- harder to erode

Question 21

How does strata with well developed joints at right angles effect erosion rates

Answer 21

• gives a place to attack
• is a weakness
• faster