weather erosion and deposition Flashcards

1
Q

define weathering

A

the chemical and physical weathering of rocks near earth’s surface

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2
Q

Define chemical weathering

A

The breakdown of rock through a change in mineral or chemical composition

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3
Q

What are two examples of chemical weathering

A
  1. oxidation
  2. when water dissolves minerals
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4
Q

What forms caves

A

the chemical breakdown of underground limestone when rainwater picks up carbondioxide and become acid rain

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5
Q

Define acid rain

A

rainwater that picks up carrbon dioxid

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6
Q

define physical weathering

A

The breakdown of rock into smaller pieces without changing its chemical composition

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7
Q

what are the 4 causes of physical weathering and explain them

A
  1. Frost wedging - the repeated freezing and thawing of water within rocks -causes crack to become bigger and bigger
  2. plant root growth - root growth with in rock that breaks it apart
  3. abrupt temperature change - temperatur changes cause rocks stress which can result in change withing the rock like expansion and contraction
    4.ABRASION - when sediments moved by ice, water, wind or gravity grind against other rocks
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8
Q

What are the factors that affect the rate and type of weathering and explain them

A
  1. Exposure to Air- rocks abrove ground weather faster than rocks buried underground
  2. Particle Size - with equal volumes of rock smaller particle weather fasster than larger particles (larger particle have a greater surface area)
  3. Mineral composition - Different minerals weather at different rates based on their properties
  4. Climate -
    climates effects when chemical weathering works best and when physical weathering works best (chemical more effective in warm and moist and physical more effeictive in cold and moist)
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9
Q

define erosion

A

the movement of weathered rock

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10
Q

what are the 6. agents of erosion

A

Gravity, Running water and streams (most common transport agent of erosion), wind erosion, Glacial Erosion, Erosion due to waves and currents, erosion by humans

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11
Q

Define gravity agents of erosion -

A

The primary force behind most types of erosion

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12
Q

What creates mudslides

A

gravity aided by water creates mudslides

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13
Q

what is it called when gravity acts alone?

A

mass wasting or mass movement

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14
Q

How is sediment transported through streams?

A
  1. dissolved minerals flow in solution
  2. Small sediments (clay) are suspended in the water
  3. larger sediment (pebbles) burow allong the bottom and become rounded THIS IS STREAM ABRASION
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15
Q

how are valleys formed

A

from river/ stream erosion and mass movemnt of rock

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16
Q

What shape does a stream carve in a valley over time

A

a V

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17
Q

What are the three things that determine the velocity of a stream

A

Gradients- Slope of the stream (as gradient increases so does stream velocity)
Discharge - volume of water in the stream (as discharge increases so does stream velocity)
Stream channel Shape - straightest streams flow faster than meandering streams

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18
Q

What is the mouth of the stream

A

THE END OF A STREAM

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19
Q

How were the Finger lakes formed

A

beggining of a stream that was carved by glaciersd

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20
Q

meanders def -v

A

when a stream bends and turns downstream

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21
Q

What is a Channel-

A

a waterway (or stream) that connects to areas of water

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22
Q

What will happen as a stream flows through its channel?

A

its velocity will change due to the curvature of the stream

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23
Q

What is wind erosion

A

strong winds can pick up small particles (sand grains or smaller) and blown the about

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24
Q

Examples of wind erosion and explain them

A

Sandblasting - when winds blow sand or silt grains against rock causing abrasion
Deflation - when wind blows away loose sediment causing the land surface to lower

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25
Q

Whats Glacial erosion -

A

when glaciers move rock through movements, acts like sandpaper scratching away at earth’s surface

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26
Q

Define a glacier -

A

ice and snow that moves downhill under the influence of Gravity

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27
Q

How do glaciers move

A

. Glaciers advance when more snow and ice is added
.glaciers retreat when they melt
* just like rivers glaciers flow faster in the middle

28
Q

What are glacial grooves

A

grooves on earth’s surface that show the direction it moved

29
Q

What are glacial erratics -

A

Large boulders that are picked up by the glacier and deposited ina new location

30
Q

what are glacial valleys

A

vall carved by glaciers in a U shape

31
Q

explain crashing waves on rock

A

When waves crash on rock it braeks it down into smaller and smaller pieces over tiem

32
Q

The pouding surf -

A

A tremendous amounts of energy is released when waves break

33
Q

What is long shore drift

A

water flwoing along the beach due to the repeated action of waves crashing onto the beach at an angle

34
Q

What helps lessen beach erosion

A

Jetties

35
Q

Sandbar -

A

bar of sand formed due to the deposition of wave erosion

36
Q

Erosion by humans -

A

human activities such as contruction and deforestation expose more sedimetn, thereby incresing erosion

37
Q

Define deposition -

A

Process by which the agents of erosion drop their sediment

38
Q

what are the two types of deposition

A

deposition of solid sediments

precipitation - release of dissolved minerals such as salts from a water solution

39
Q

what does crystillization result in?

A

ROCKS COMPOS3ED OF ONE ELEMTNT

40
Q

HOW DO HUMANS BENEFIT FROM DEPOSITION

A

WE MINE MANY OF THE DEPOSITED SEDIMENTS FOR VARIOUS THINGS

41
Q

What causes deposition to occur

A

deposition usually occurs when the velocity of a stream or wind slows or stops

42
Q

what is the rate of deposition

A

howmuch is deposited over a distance

43
Q

how does velocity affect the rate of deposition

A

as velocity decreases it will deposit the sediments it can no longer carry

44
Q

How do sediment characteristics affect the rate of deposition

A
  1. sediment size- bigger sediments settle first when wind or water slows down
  2. sedment shape - the more rounded a sediment the faster it will settle out of air or water
  3. sediment density - the higehr the density the faster sediment will settle out of air
45
Q

As density increase what happens to settling raate and settling time

A

settling time decreases and settling rate increases0

46
Q

When is deposition considered sorted?

A

when the deposit has particles are simlar in size

47
Q

When is deposition considered unsorted

A

when the deposit has mixed sediments

48
Q

What is vertical sorting

A

When a mix of sediment settles out rapidly a layer graded bed forms with the sediment size increasing
from small to big

49
Q

What is horizontal sorting

A

when streams enter oceans and gradually deposit sediment where the larger sedimetns settle first result in horizontal layers which decrease in sediment size with distance from the source

50
Q

UNSORTED GLACIAL AND MASS MOVEMENT DEPOSITS

A

when glacier or gravity deposit their sediment the result is a maix of sizes shapes and densities (unsorted)

51
Q

Energy transformation in a stream

A

the stream loses enrgy as it moves from its source to its mouth

52
Q

when is kinetic energy highest

A

when theres erosion

53
Q

when is kinetic energy low

A

when there is deposition

54
Q

How is a stream in a constant equilibrium

A

when sediment is eroded upstream in eventually deposited downstream

55
Q

2where does more deposition occur

A

in the floodplain

56
Q

where does most deposition occur in a strem and whast does it form

A

mostly it occurs at the mouth formeing a delta

57
Q

What is a delta

A

a fan shaped deposit of sediments at the end of a stream

58
Q

what happens to the sediments at the front of the glacier

A

teh sediment is dropped in unsorted pils called morains

59
Q

what are drumlins

A

unsorted glacial deposits shaped like an upside down spoon

60
Q

what are kettle lakes

A

lakes formed from blocks of ice that break off of the glacier and creat a depression that reaches the water table

61
Q

what are outwash plains and how are they formed

A

sorted deposits formed when glaciers melt and streams form carrying glacial sediment

62
Q

how are beaches formed

A

when waves deposit sediment

63
Q

what happens if a sandbar is higher than sea levvel?

A

tits considered a barrier island (fire island)

64
Q

how does wind deposit sediments

A

it blowsm sand sized grains and smaller() clay and silt = dust

65
Q

WHAT DO AVALANCHES AND LANDSLIDES DEPOSIT ?

A

UNSORTED SEDIMENT

66
Q

why cant we see craters everywhere on earth

A

earths hydrospher and atmospher do a great jpb destroyign meteorites