Rocks Soils and Plants

Question 1

Define weathering.

Answer 1

The chemical alteration and mechanical breakdown of rocks

Question 2

What does weathering convert rock to? What is that then converted to?

Answer 2

Saprolite then soil

Question 3

Define saprolite.

Answer 3

In-situ weathered rock

Question 4

What is another name for salt action?

Answer 4

Haloclasty

Question 5

What is salt action? What does it leave behind?

Answer 5

Aka haloclasty
Growth of salt crystals in rock, push apart and separate rock
- When the salt crystals blow away/dissolve a honeycomb formation is left behind

Question 6

What is the volume increase of ice compared to water?

Answer 6

9%

Question 7

What other weathering process is very similar to salt action?

Answer 7

Frost weathering

Question 8

Describe frost weathering. How does it sustain itself?

Answer 8

Frost opens up cracks in rocks when water freezes and expands, these cracks then expose more of the rock to frost weathering

Question 9

What are some examples of plants weathering rocks?

Answer 9

Roots expanding rock cracks
Upheaval of rocks when plants disturbed
Retention of water within rocks (allowing for water/frost weathering)
Organic acid excretion from roots (or from decomposition of organic matter)
Encouraging biota to graze and disturb rocks

Question 10

Name four types of chemical weathering.

Answer 10

Hydrolysis
Acid dissolution
Redox reactions
Chelation of polyvalent metals

Question 11

What was the impact of an increase in root complexity across time?

Answer 11

Higher rates of weathering

Question 12

Which increases with higher temp and rainfall, chemical weathering rates or mechanical weathering rates?

Answer 12

Chemical rates

Question 13

Which increases with low temperatures and low rainfall, chemical weathering rates or mechanical weathering rates?

Answer 13

Mechanical rates

Question 14

Which group is more susceptible to weathering, granite and rhyolite or gabbro and basalt?

Answer 14

granite and rhyolite

Question 15

How does the impact of Specific surface area of a rock on its weathering rates perpetuate a cycle of weathering?

Answer 15

Weathering increases exposed surface area which increases weathering rates which increases SSA etc etc

Question 16

Give some examples of ultrabasic igneous rocks.

Answer 16

Olivine, peridotite, basalt

Question 17

What sort of elements are igneous ultrabasic rocks high and low in?

Answer 17

High = magnesium, nickel, iron, chromium
Low = calcium, potassium, phosphorous

Question 18

What do the component elements of ultrabasic rocks mean for the soils formed from them?

Answer 18

Low in essential nutrients while high in damaging elements

Question 19

What are zonal soils?

Answer 19

Well developed soils that reflect that the climate was the major soil forming factor

Question 20

What are intrazonal soils?

Answer 20

Well-developed soils where some local factor is dominant

Question 21

What are azonal soils?

Answer 21

Those that are immature or poorly developed

Question 22

What sort of plants grow on ultra-basic intrusive rock soils?

Answer 22

Highly selective, endemic floras

Question 23

What type of soils form on acidic intrusive rock?

Answer 23

Zonal soils on gentle landforms but azonal on steep landforms

Question 24

What sort of soils form on ultrabasic extrusive rocks?

Answer 24

Zonal with good diversity

Question 25

What sort of soils form on acidic extrusive rocks?

Answer 25

Azonal soils with poor nutrient levels

Question 26

What is the difference between sandstone and shale soils?

Answer 26

Sandstone = acidic, free, draining
Shale = less acidic, less free, still draining

Question 27

Sandstone and shale are both examples of what?

Answer 27

Clastic rocks

Question 28

What kind of soils form from limestone? What kind of plants grow?

Answer 28

Alkaline soils and specialist plants

Question 29

What’s the major difference in soils between Dark Peak and White Peak in the Peak District? How does this affect plants and why is that notable?

Answer 29

Dark - acidic moorland dominated by heather
White - alkaline grassland with rich biodiversity
Notable because the two are very close but have radically different biodiversity due to their underlying geology

Question 30

What plants grow on the abandoned lead mines of the Peak District?

Answer 30

Metallophytes, incredibly specialised plants

Question 31

Where else are metallophytes notably seen outside the UK? What metals do they live ‘on’ here?

Answer 31

Central African Copperbelt
- Copper and cobalt

Question 32

How can metallophytes be used for profit?

Answer 32

Mineral prospecting as they can be indicators of mineral presence

Question 33

What plant only grows on copper rich soils/ as a diamond indicator?

Answer 33

Viscaria

Question 34

Define Phytoremediation.

Answer 34

Removal of minerals through uptake from the soil by certain plants

Question 35

How can Phytoremediation be used to benefit the environment?

Answer 35

Can be used to clean up contaminated areas (from hazardous industry)

Question 36

What does removal rate measure?

Answer 36

The rate at which a plant draws a mineral/metal from the soil it grows in