Weathering

Question 1

What does endogenic mean

Answer 1

Within the earths surface eg plate tectonics

Question 2

What does exogenic mean

Answer 2

At or very near the earths surface eg denudation

Question 3

What is denudation

Answer 3

The break up of rock and removal of the broken material

Includes, weathering, erosion and mass movement

Question 4

Weathering is influenced by

Answer 4

Rock type eg rocks with bedding planes are easier to break down
Climate influences type of weathering and speed
Topography, upland areas are more exposed to weathering

Question 5

Two types of weathering

Answer 5

Physical (mechanical)

And chemical

Question 6

What does physical weathering change

Answer 6

Physical appearance of rock

Question 7

Two types of physical weathering

Answer 7

Freeze thaw (frost wedging)
Exfoliation (onion weathering)

Question 8

Conditions needed for freeze thaw

Answer 8

Adequate supply of water
Rock has pre existing fractures and joints
Temperature regularly rises and falls

Question 9

How much does water expand when turning into ice

Answer 9

9%

Question 10

What is scree

Answer 10

Broken material made when rock is weathered

Question 11

Example of freeze thaw in Ireland

Answer 11

Sugarloaf Wicklow

Carrontoohil Kerry

Question 12

What is diurnal temperature range

Answer 12

Big difference between the highest and lowest temperature

Question 13

Temperatures in desert at day

Answer 13

40° c +

Question 14

Temperatures in desert at night

Answer 14

0° c

Question 15

Why is it so hot in the desert during the day

Answer 15

Lack of cloud

Lack of vegetation

Question 16

Example of exfoliation

Answer 16

Half dome in Yosemite national park

Question 17

What is chemical weathering

Answer 17

The decay of rocks and change in chemical makeup

Question 18

Where does chemicals weathering work best

Answer 18

Hot, humid conditions

Question 19

Two types of chemical weathering

Answer 19

Carbonation

Hydrolysis

Question 20

What does a weak carbonic acid consist of

Answer 20

Rain water and carbon dioxide from atmosphere and soil

Question 21

What rocks erode best

Answer 21

Limestone and chalk, bedding planes

Question 22

Example of landscape weathered by carbonation

Answer 22

The burren co Clare

Marble Arch caves, Fermanagh

Question 23

What does hydrolysis do to the rock

Answer 23

Reacts with chemical breaking in into a softer and weaker material.

Question 24

Example of hydrolysis in Ireland

Answer 24

Leinster batholith soil

Question 25

Why is hydrolysis important

Answer 25

Makes healthy soil

Question 26

Explain freeze thaw action

Answer 26

``` Occurs when temperatures move above and below freezing Adequate rainfall Pre existing fractures 9% size increase from water to ice Expand cracks Cycle Scree ```

Question 27

Explain exfoliation

Answer 27

``` Large diurnal temperature range Deserts (day 40° and night 0°) No clouds and lack of vegetation Rock expands when heated Contracts when cooled Outer layers heat up quicker Flakes- large slabs of scree Newly exposed outer layers - cycle continues ``` Darker absorb more light and different minerals cause to expand at different rates eg quartz quicker than feldspar

Question 28

Explain carbonation

Answer 28

Rainwater absorbs carbon dioxide from atmosphere and soil Makes a weak carbonic acid Acid dissolves rock, changing minerals Calcium carbonate changes to calcium bicarbonate Sinks through rock Mostly limestone - clints, grikes, easy access

Question 29

Explain hydrolysis

Answer 29

Water reacts with chemicals in the rock making it softer and break down Fine grained rock quicker to break down Affected by temperature - every 10° increase, rate doubles Eg Brazil rainforest 20m deep soil Acidic water changes feldspar to kaolin. Clay like material Feldspar was the glue that held everything together but now rock begins to crumble Leinster batholiths