Rock Studies

Question 1

What are the three types of rock ?

Answer 1

1. Igneous ( cooling magma): granite ( inside the earth), basalt ( on the earth)
2. Sedimentary ( sediments): sandstone, limestone
3. Metamorphic ( heat and pressure): marble and quartzite

Question 2

What is denudation ?

Answer 2

It’s the process of breaking down rocks. It’s caused by both weathering and erosion.

Question 3

What are the two types of denudation ?

Answer 3

1. Weathering ( mechanical and chemical weathering )
2. Erosion ( moving water, ice and air )

Question 4

What are the types of mechanical weathering?

Answer 4

1. Freeze-saw action
2. Exfoliation
3. Pressure release
4. Salt crystallisation

Question 5

Describe freeze-thaw action

Answer 5

1. Frequent temperature change ( temperature rise and fall below 0 )
2. Plentiful supply of water
3. Most pronounced at higher altitudes
4. Day: water seeps into cracks or fissures in the rock
5. Night: water freezes and expands straining the surrounding rock. Rocks scrumble and break down ( scree)

Question 6

Descrine Exfoliation

Answer 6

1. Large diurnal temperature range
2. Rock expands during the heat of the day and contracts ar night
3. It exerts on the rock and the outside layers of the rock shatter

Question 7

Describe pressure release

Answer 7

1. Denudation removes the rock material
2. Underlying rock is exposed and pressure is released
3. Outer layers of the rock expand, which creates stress on the rock
4. It leads to fracturing parallel to the rock’s surface
5. Sheets I’d rock break away from the exposed rock along fractures

Question 8

Describe salt crystallisation

Answer 8

1. It’s associated with arid climates
2. High temperatures cause strong evaporation
3. It causes the breaking down of rocks when a salt solution seeps into cracks
   4.It evaporated and leaves salt crystals behind
4. Salt crystals expand when they are heated up, thus exercin gpressure on the rock, which leads to it’s disintegration