Brainscape's Knowledge GenomeTM

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


See full index

Geology 108 Final > Final Study Guide 12 > Flashcards

Final Study Guide 12 Flashcards

Deserts and Desertification

1
Q

What is desertification?

A
  • The process by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture. Such as sand dunes moving often and desert taking over. Increase in temperature and change in wind pattern drive desertification.
  • Desertification is the expansion of desert areas (deserts: Deserts are, according to some climatologist, a “dry” region, i.e one in which yearly rainfall is less than the potential evaporation rate in that region).
  • Process governed by:
    > how close to certain temp range likely for turning land into a desert
    > type of vegetation→ taking away vegetation in which roots normally stabilize ground. No stabilization = deflation (easier to erode the ground material)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What determines the geographic location of deserts?

A

Mainly things such as rain fall amount, wind/atmospheric circulation, temperature, climate, and orographics (rain shadow effect)

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

What are the possible impacts of sandstorms, locally and globally?

A
  • Sand storms interrupt air/ground traffic, create big wind/season climate variations, destroy vegetation, low visibility and diseases.
  • Carry sand to different places locally and even across oceans to help enrich soils and sustain beaches.
  • The sand from these storms stays in the atmosphere and is dangerous because it settles at the deepest part of your lungs
  • Seasonal climate variation
  • Drastic changes in weather and climate due to changes in albedo
  • Air pollution is enhanced by sandstorms
    > Beijing and Gobi Desert
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Desert

A
  • “dry” regions in which yearly rainfall is less than the potential evaporation rate in that region
    > features: topography, latitude, away from oceans, human impact
    > Develop because of: atmospheric circulation, location within continental interiors, or orographic (rain shadow) deserts.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Sandy desert

A

Ex: Great Sandy Desert, Australia

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

Rocky desert

A
  • Ex: Mojave in CA

- Cacti

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

Devil’s racetrack

A

huge boulders that leave a track on the surface of a dried lake bed

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

Sandstorms

A
  • Jets of sand being transported by wind
  • Seasonal
  • Interrupt air traffic
  • Enhance air pollution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Particulate smog

A

?

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

Precipitation

A

?

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

Evaporation

A

The change of state from a liquid to a gas form. This typically happens with liquids that come in contact with energy or heat and rise into the air as vapor

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

Low Latitude Desert

A
  • closer to the equator where the sun is hotter and heats sand more
  • Hot sand heats air→air rises→prevents cool, moisture filled air from lowering and prevents precipitation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Orographic desert

A
  • Desert caused by a rain shadow

- Receive little moisture due to rain shadow

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

Rain Shadow

A
  • dry area on the side of a mountain away from the wind

- Mountains block the passage of rain-producing weather systems and cast a dry shadow

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

Kalahari

A

Large, semi-arid, sandy desert in southern Africa

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

Sahara

A
  • World’s hottest desert and third largest

- Huge sand dunes

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

Gobi

A
  • a type of desert, the advance of Gobi Desert Dunes in China
  • Rock floor desert plain
18
Q

Trade winds

A
  • Prevailing pattern of easterly surface winds found in the tropics (near the equation), within the lower portion of earth’s atmosphere
  • Blow from northeast in the northern hemisphere and from the southeast in the southern hemisphere
  • East→West
19
Q

Westerlies

A
  • Prevailing pattern of winds in middle latitude between 30-60 degrees
  • Blows West→East
  • Affects ocean currents
20
Q

Taklamakan

A
  • Desert in China
  • Shifting sand desert with lots of dunes
  • Lies in rain shadow of Himalayas→cold desert climate
21
Q

Sierra Nevada

A
  • Snowy mountain range in CA and NV

- Casts a rain shadow into the Great Basin

22
Q

Vulnerability

A

?

23
Q

Desertification

A

The process by which fertile land becomes desert

24
Q

Wind erosion

A

?

25
Q

Settling velocity

A

the faster settling velocity = thicker particles

26
Q

Turbulence

A

?

27
Q

Wind shadow

A

?

28
Q

Dune formation

A
  • Dunes can form in different ways, but often from saltation

- Saltation: particle transport by wind or water

29
Q

Vortex

A

?

30
Q

Stream lines

A

direction of wind movement

31
Q

Slip face

A

Also known as “Lee face” , side of mountain that does not get wind

32
Q

Deposition

A

the laying down of sediment carried by wind, water, or ice. Sediment can be transported as pebbles, sand & mud, or as salts dissolved in water. Salts may later be deposited by organic activity (e.g. as sea-shells) or by evaporation

33
Q

Critical angle

A

34 degrees

34
Q

Sand stone

A
  • clastic sedimentary rock composed mainly of sand-sized minerals or rock grains
  • Rock formations of sandstone are porous enough to store large quantities of liquids–good aquifers as they also filter out pollutants
35
Q

Barchan

A

Crescent shaped dunes with horns pointing downwind

36
Q

Transverse dune

A

Linear dune that moves perpendicular to the wind

37
Q

Longitudinal Dune

A

Linear dune that moves parallel to the wind

38
Q

Avalanche

A

rapid flow of snow down a sloping surface

39
Q

Desert Pavement

A
  • packed surface coating of rocks, usually above a layer of windblown dust
  • Two proposed ways:
    > Deflation→remove finer particle→desert pavement established→deflation ends
    > Weathered pebbles on bedrock→wind-blown silt accumulated and sifts downward through coarse particles→silt continues to accumulate→makes desert pavement
40
Q

Desert varnish

A
  • A layer of minerals formed over long times, by means of chemical interactions between the rock and the little humidity you find in deserts
  • Very slow process; 1mm can take up to 1,000 years
41
Q

Deflation

A
  • Wind or water picks up and carries small particles
  • Three types:
    > Surface Creep: larger, heavier particles, slide or roll across the ground
    > Saltation: particles are lifted a short height into the air, bounce, and transported
    > Suspension: very small & light particles are lifted in the air and carried a long way by the wind

Geology 108 Final (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions