weathering Flashcards

(46 cards)

1
Q

denudation

A

lowering of continental surfaces

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2
Q

3 elements of denudation

A
  1. weathering
  2. mass wasting/mass movement
  3. erosion
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3
Q

weathering AKA

A

how to lower

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4
Q

two types of weathering

A
  1. physical
  2. chemical
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5
Q

physical weathering

A

breaks down big rocks into smaller pieces BUT the chemical composition does NOT change

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6
Q

physical weathering AKA

A

disintegration

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7
Q

chemical weathering

A

big rocks are broken down to smaller rocks WITH their chemical composition changing (become new rocks)

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8
Q

chemical weathering AKA

A

decomposition

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9
Q

mass wasting is

A

the transfer of material downhill via GRAVITY

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10
Q

erosion is the

A

transfer of material by water, wind or ice

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11
Q

weathering is the

A

IN SITU breakdown of rock

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12
Q

what are 4 thing that control weathering

A
  1. rock properties
  2. climate
  3. soil and vegetation
  4. length of exposure
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13
Q

how are some rock properties affect weathering

A
  1. hardness
  2. composition
  3. solubility
  4. zones of weakness aka joints
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14
Q

how does climate affect weathering

A

depending on the temp and moisture, it can either accelerate or inhibit weathering

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15
Q

how do soil and vegetation affect weathering

A

exposes rock to variations in moisture and chemistry

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16
Q

physical weathering AKA

A

mechanical weathering

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17
Q

physical weathering converts rock into smaller pieces that can be act on more by

A

erosion

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18
Q

how do physical weathering and surface area relate

A

as the rock is broken down to smaller pieces, there is more surface area

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19
Q

an increase in surface area by physical weathering allows for _____

A

more reactions to take place

20
Q

important physical weathering processes

A
  1. frost action
  2. salt weathering
  3. pressure-release jointing
  4. biological forcesq
21
Q

what is frost action

A

the weathering processes caused by repeated cycles of freezing and thawing

22
Q

describe the process of frost action

A

meltwater leaks into cracks and freezes causing fissures to expand under pressure and, with repeated cycles, shatter the surrounding rock.

23
Q

where does frost action take place

A

in places that often go through rises and falls in temp through zero (like the Himalayas)

24
Q

salt crystal growth process

A
  1. as water evaporates, it leaves salt in the rocks
  2. over times the crystallization breaks apart the rock
25
where does salt crystal growth happen
1. dry environments 2. areas with lots of ocean spray
26
pressure-release jointing process
1. rocks in the surface are exposed to high levels of pressure and heat that stick them together 2. as they reach the surface, there is less pressure which causes them to break apart
27
what is the result of pressure-release jointing
slab-like layers or sheets break loose
28
how can biological activity act as physical weathering of rocks
1. plant roots can break up the rock as they push through 2. some animals can break rocks as they make homes (clams)
29
what does chemical weathering involve reactions between
air and water and minerals in the rock
30
where is chemical weathering going to occur FASTER
in places with warm temps and lots of water
31
why does chemical weathering happen in places with lots of water and warm temps
because these conditions promote faster chemical reactions
32
how can chemical weathering accelerate physical weathering
it makes the rocks more susceptible to physical weathering as the crystal structures are disrupted
33
important chemical weathering processes
1. hydrolysis and hydration 2. dissolution of carbonates
34
hydrolysis is the _____ of a molecule by the _____ of a water
breaking and addition
35
what do the free hydrogen or hydronium ions in WATER do in hydrolysis
participate in chemical reactions that make NEW compounds
36
what can be the result of hydrolysis
crystal structure of weaker minerals may breakdown = granular disintegration
37
dissolution of carbonates
reaction where carbon combines with minerals and dissolves them
38
what forms in the dissolution of carbonates
weak carbonic acid (water and carbon dioxide)
39
dissolution of carbonates is related to
kast topography
40
kast topography
the solution of carbonate rock results in a landscape of pitted, bumpy surface with vast underground channels or caverns
41
what are the 3 conditions for karst topography
1. rocks with equal or over 80% calcium carbonate AND have jointing 2. climate must be warm and moist 3. there must be vegetation to increase CO2 in soil
42
where do physical/mechanical weathering dominant
drier, cooler climates
43
where does chemical weathering dominant
moister, wetter climates
44
benefits of weathering
1. produces parent material for soils 2. releases/produces minerals not able to be access another way
45
4 categories of soils
1. gravel 2. sand 3. silt 4. clay
46
order of soils based on largest to smallest particle size
1. gravel 2. sand 3. silt 4. clay