Unit 1 - AOS2 - Lithosphere

Question 1

Earths Crust

Answer 1

• Made from slabs of igneous rocks and soil
• 40km under continents and 10km under oceans

Question 2

Order of the earths layers

Answer 2

1. Lithosphere (crust + upper mantle)
2. Mantle (the rest of it)
3. Core
   - Outer core: molten and composed mainly of nickel and iron
   - Inner core: composes mainly of iron and is solid due to pressure/weight.

Question 3

Continental drift

Answer 3

The movement of the plate tectonics on earth, at different rates and directions.
- Move slowly (1-12cm per year)

Question 4

Convection currents

Answer 4

Is when molten material in the mantle moves, nudging the plate tectonics and causing them to move.

Question 5

Transform-fault boundaries

Answer 5

• Slide horizontally past each other
• Cause earthquakes

Question 6

Divergent Boundaries

Answer 6

• Plates move apart creating new lithosphere
• Forms mid ocean ridges and rift valleys
• Characterized by volcanic activity and earthquakes

Question 7

Convergent boundaries

Answer 7

When plates collide (one is pulled into the mantle and recycle)

Question 8

Igneous rocks

Answer 8

Form from the cooling of magma –> that did not reach the surface.
e.g: basalt, obsidian

Question 9

Sedimentary Rocks

Answer 9

Form from deposits or eroded particles of rock, soil and remains of dead organisms
- Overtime increased pressure on the layers compresses them into rocks

e.g. limestone, conglomerate

Question 10

Metamorphic Rocks

Answer 10

Are igneous or sedimentary rocks that have been altered by heat, pressure and change within earth’s crust.

e.g. marble, gneiss

Question 11

Weathering (rocks)

Answer 11

• Breaks down and sculpts the rocks

Question 12

Erosion

Answer 12

Erosion transports fragments of rocks

Question 13

Deposition

Answer 13

Rocks and minerals that were weathered and eroded, are deposited into another place.

Question 14

Define soil

Answer 14

Mixture of particles that have been formed over long periods of time by the weathering rocks and remains of eaf organisms.

Question 15

Define Humus

Answer 15

Decomposing organic material
- highly fertile

Question 16

How do worms help with soil ?

Answer 16

• help turn the soil bringing humus from top soil and mix with the other layers of soil

Question 17

What does the proportion of particles determine ?

Answer 17

It determines the texture of the soil
And therefore the properties :
- aeration
- density
- drainage
- capacity to hold water and nutrients

Question 18

Define Loam

Answer 18

It is the best soil for growing crops in due to it having equal ratios of sand, silt and clay

Question 19

Porosity

Answer 19

Is the size of the space between each particle
- allowing water and air to penetrate through the soil

Question 20

Sandy soil characteristics and porosity

Answer 20

• allows water to pass through quickly
• high porosity

Question 21

Clay soil characteristics and porosity

Answer 21

• retains water for long periods making it water logged

Question 22

Layers of soil

Answer 22

• 0 organic matter = humus
• A horizon = topsoil
• B horizon = subsoil
• C horizon = substratum

Question 23

Marble

Answer 23

• metamorphic
• included crystals and is when limestone is compressed into the earth and subjected to heat and pressure

Question 24

Conglomerate

Answer 24

• sedimentary
• includes pebbles, stones and smaller particles and is compressed together from waves or water

Question 25

Obsidian

Answer 25

• igneous
• smooth glassy surface
• created from lava or magma that cools so quickly no crystals can be formed

Question 26

Basalt

Answer 26

• igneous
• is cooled lava that contains gases from volcano
• creates gas bubbles

Question 27

Limestone

Answer 27

• sedimentary
• fossils are visible in the rock
• fossils formed from seashells and skeletons from dead marine animals are compressed into the sea floor.
  With other sediments

Question 28

Gneiss

Answer 28

• metamorphic
• Ribbon like layers
• forms from other rocks being pressurised with heat deep within the earths crust