Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Dynamic Earth: Physical Geography > Weathering > Flashcards

Weathering Flashcards

1
Q

tallis slope

A

slope of highly angular rock fragments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

4 main factors on weathering

A

water, chemical enviro., pressure, temp.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

equifinality

A

different processes leading to the same rock type or formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

4 key components in the weathering system

A

process, materials, form and environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

4 important effects of rock breakdown

A

soil formation, landscape and landform evolution, prepares rock for erosion and transportation, dissolved nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

4 products of weathering systems

A

physical particles, chemicals dissolved in water in form of ions, oxides, clay minerals from chemical trans of minerals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

explain weathering feedback

A

landforms produced by weathering will influence further weathering-> increased surface area makes rock break down more quickly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

3 types of weathering

A

physical, chemical, biological

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

explain dilation weathering

A

removal of overlying material over an igneous dome leads to pressure release, joints and fractures, top layer breaks up-> more uplift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

two features formed from dilation

A

exfoliation dome, exfoliation sheet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

explain thermoclasty

A

driven by sun, forest fires, lightning strikes. thermal shock when temp. changes so rapidly that rock cracks.
fatigue failure, repeated app. of stress
granular disintegration- grain by grain weathering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how much does water expand by when frozen

A

9%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what temp is needed for effective ice expansion in freeze-thaw

A

-22C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

difference between macro and microgélivation

A

macrogélivation: large blocks get broken off, microgélivation: granular disintegration and flaking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

explain salt crystal weathering

A

water evaporates to leave salt behind, grows, wedges rock apart
micropores allow movement of saline solution into pores
causes flaking, alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are tafoni

A

larger alveoli (cavernous weathering)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

where does salt weathering mostly occur

A

desert and coastal environments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

explain hydration weathering

A

water into rock, water molecules attach to crystalline structure of mineral, expansion when hydrated, mineral grains flake off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

which out of the two main controls is most influential on weathering

A

climate but can be overtaken by material factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

substance that increases the proton conc. of water

A

acidic/proton donor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

substance that decreases the proton conc. of water

A

proton acceptor/base

22
Q

what is the most common proton donor in nature

A

carbonic acid

23
Q

redox potential (Eh)

A

ability of a chemical species to bring about an oxidation or reduction reaction

24
Q

what is solubility in natural environments dependent on

A

pH and Eh, both of which are influenced by temp.

25
Q

give characteristics of water that allows it to weather physically

A

high cohesiveness, high surface tension, high capillarity, freely changes from solid to liquid to gas

26
Q

slaking

A

alternate wetting and drying that causes materials to disintegrate and crumble

27
Q

explain hydrolysis

A

chemical reaction between mineral and slightly acidic water to break bonds of a partic. substance. congruent dissolution: metal cations selectively replaced in the crystal lattice and minerals altered into clay minerals

28
Q

what minerals are especially affected by hydrolysis

A

feldspars

29
Q

what minerals can carbonation weather

A

carbonate, silicate and ferro-magnesium minerals

30
Q

why is limestone dissolved more quickly beneath soil

A

soil carries a higher conc. of dissolved CO2

31
Q

how does temp affect carbonation

A

partial pressure of CO2 falls with a rise in temperature so colder temps may lead to more weathering. (but other factors at play)

32
Q

how do oxidation and reduction transform substances

A

addition and removal of oxygen

33
Q

what is chelation

A

metal ions are kept in solution and prevented from precipitating within plant roots-> causes the removal of these cations by ion exchange, replaced by hydrogen ions which acidify soils

34
Q

give example of bacteria that weathers rock

A

cyanobacteria cause locally concentrated weathering and erosion

35
Q

function of lichens

A

communities of fungi and algae, bioprotectors, can promote weathering by excreting organic acids or prevent it by producing oxalic acid (quite insoluble coating on limestone)

36
Q

resistates

A

unaltered primary materials basically immune to a specific process that survive while surrounding rocks are weathered away

37
Q

what are secondary materials

A

weathering products of primary materials

38
Q

what determines the composition of clay material in secondary materials

A

the initial material and the intensity/duration of weathering

39
Q

how are sandy regoliths formed

A

minerals less susceptible to weathering continue to break down into smaller fragments

40
Q

what causes thermal shock (type of thermoclasty)

A

sudden temp change doesnt allow time to expand/contract quickly enough. adjacent crystals heat and expand at diff rates

41
Q

give factors that can prevent or slow down freeze-thaw

A

increased pressure during ice formation can lower freezing point and slow further freezing, impurities slow down freezing, rocks not at near saturation

42
Q

does salt weathering occur through shock or fatigue

A

fatigue

43
Q

what are the three main processes at work in salt weathering

A

crystallisation, hydration, differential thermal expansion

44
Q

what is granular disaggregation

A

salt weathering of some rocks results in larger grains formed

45
Q

what is efflorescence

A

the near-surface accumulation of salt

46
Q

contour scaling

A

the accumulation of salt in the subsurface zone leads to surface layer blistering and falling away

47
Q

cavernous weathering

A

salt weathering creates hollows where salts are retained, microclimates= moister and cooler, deeper absorption of salt = further weathering

48
Q

how can fungi and lichens weathering through hydration

A

turgor pressure

49
Q

5 methods of physical weathering

A
  1. unloading, dilation, pressure release
  2. thermal expansion and contraction (thermoclasty)
  3. freeze-thaw
  4. salt crystal growth
  5. hydration
50
Q

grus

A

accumulation of angular, coarse-grained fragments resulting from granular disintegration (usually in arid regions)

51
Q

why is salt weathering more common in coastal and desert enviros

A

great temp range and moisture containing salt exists

Dynamic Earth: Physical Geography (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions