Unit 5: 18, 19, 20

Question 1

What is cross bedding?

Answer 1

when sedimentary rock layers become folded and bent

Question 2

How is cross bedding formed?

Answer 2

geological shifting

Question 3

Describe an erg desert

Answer 3

sea of sand – large area covered with loose sand generally arranged in some sort of dune formation by the wind

Question 4

Describe a reg desert

Answer 4

stony deserts – desert is covered in a layer of stones, which can sometimes be very thin. the finer material being removed, the surface pebbles often fit closely together, sealing whatever material is below from further erosion

Question 5

Describe a hamada desert

Answer 5

barren bedrock – exposed bedrock, but sometimes is composed of sedimentary material that has been cemented together by salts evaporated from groundwater.

Question 6

Know the origin of loess

Answer 6

winds remove loess from glacial outwash plains

deflation of desert regions

Question 7

What is loess’s economic importance to farmers?

Answer 7

Loess deposits provide fertile possibilities for agriculture, for they serve as parent material for some of the world’s most productive soils, especially for growing grain

Question 8

What are some characteristics of barchan sand dunes?

Answer 8

individual dune migrates across a nonsandy surface, although they may be found in groups. crescent shaped, with the horns facing downwind. form where strong winds blow consistently from one direction

Question 9

What are some characteristics of transverse sand dunes?

Answer 9

also crescent shaped, but less uniformly than barchans. occur where the supply of sand is much greater than that found in locations that have barchans; normally the entire landscape leading to the transverse-dune formation is sand covered. if the sand supply decreases, they are likely to break up into barchans

Question 10

What are some characteristics of longitudinal sand dunes?

Answer 10

meager supply of sand
strong prevailing winds
parallel to wind direction

Question 11

What are some characteristics of blow-out sand dunes?

Answer 11

coastal blowouts have strong persistent onshore winds

large supply of sand from beaches

Question 12

Know how wind can change the character of deserts through the process of deflation.

Answer 12

shifting of loose particles

Question 13

Be able to describe arid western landscapes

Answer 13

dry

Question 14

Be able to describe humid eastern landscapes

Answer 14

humid

Question 15

What is the particulate matter theory for ice ages

Answer 15

volcanic eruption
meteor impact in the Vredefort Dome, the oldest and largest clearly visible meteorite impact structure in the world – south africa

Question 16

What is the CO2 fluxuations theory for ice ages

Answer 16

earth experiences warming period
plants spread poleward and total biomass greatly increases
greater absorption of CO2 due to greater amounts of photosynthesis occuring
lower temps bring on an ice age and much biomass reduction
reduced biomass allows for CO2 restoration to the atmosphere

Question 17

What is the warming earth theory for ice ages

Answer 17

polar regions are far colder than necessary for snow to occur
if temps rise in the polar regions greater snowfall should occur
greater snowfall causes glaciers to spread outward from the polar regions
extensive glaciation lowers polar temps and reduces snowfall
glaciers now recede

Question 18

What is the eccentricity of orbit theory for ice ages

Answer 18

angle of the tilt also varies with a 41000 year cycle
shape of the orbit varies over time - aphelion and perihelion
produces a complex series of cyclical changes in the seasonal patterns of intensity of solar radiation

Question 19

How do you determine if depositional material has been deposited by a river (stratified)

Answer 19

stratified - material is sorted by larger materials at bottom

Question 20

How do you determine if depositional material has been deposited by a glacier (unstratified)

Answer 20

unsatisfied - all mixed together sizes

Question 21

how does a glacier form

Answer 21

snowflakes compressed under pressure until density is 90% of water

Question 22

What causes a glacier to move?

Answer 22

gravity pulls it at a certain point, sometimes a lubricating layer of water on the bottom allows the entire mass to slide

Question 23

What is a mountain glaciation

Answer 23

limited to high elevations
results from surplus snow in high elevations
not necessarily dependent upon an ice age
more pronounced during ice ages

Question 24

What is a continetal glaciation

Answer 24

large geographical coverage
usually associated with major climatic change
has profound affect on landscape
occured during pleistocene

Question 25

What are eskers and how are they formed

Answer 25

These landforms are composed largely of glaciofluvial gravel and are thought to have originate when streams flowing through tunnels in the interior of the ice sheet became choked off during a time in which the ice was neither flowing nor advancing.

Question 26

What are drumlins and how are they formed

Answer 26

a low elongated hill, they are much smaller than moraines but composed of similarly unsorted till. The long axis of the drumlin is aligned parallel with the direction of ice movement. The end of the drumlin facing the direction from which the ice came is blunt and slightly steeper than the opposite end.

Question 27

What are kettle lakes and how are they formed

Answer 27

form when large blocks of ice left by a retreating glacier become surrounded or even covered by glacial drifts; after the ice block melts, the morainal surface collapses, leaving an irregular depression.

Question 28

What are kames and how are they formed

Answer 28

small, steep mounds or conical hills of stratified drift are found sporadically in areas of ice-sheet deposition. Associated with melt water deposition in stagnant ice. They are mounds of poorly sorted sand and gravel that probably formed within glacial fissures or between the glacier and the land surface. Many seem to have been built as steep fans or deltas against the edge of the ice that later collapsed partially when the ice melted.

Question 29

What are terminal moraines and how are they formed

Answer 29

a ridge of till that marks the outermost limit of glacial advance.

Question 30

What are recessional moraines and how are they formed

Answer 30

these ridges mark positions where the ice front was temporarily stabilized during the final retreat of the glacier.

Question 31

What are perennial streams

Answer 31

contains water all year round

Question 32

What are intermittent streams

Answer 32

carries water only part of the year or after rain

Question 33

What are ephermeral streams

Answer 33

carries water ONLY during or after rain

Question 34

What are exotic streams

Answer 34

stream that flows into a dry region bringing water from somewhere else

Question 35

Know why lakes with internal drainage are often salty

Answer 35

when water evaporates it leaves behind salt and minerals

Question 36

What causes beaches to build up

Answer 36

waves bring in small amounts of sand

Question 37

What causes beaches to erode down

Answer 37

waves take a small amount back. mainly storms erode beaches

Question 38

Spits

Answer 38

sediment may be moved by long shore currents into deeper water, where the flow speed is slowed and the sediment is deposited. the growing bank of land guides the current farther into the deep water, where still more material is dropped. any such linear deposit attached to the land at one end and extending into open water in a down-current direction is called a spit.

Question 39

Hooks

Answer 39

spits curve toward mainland b/c of water patterns

Question 40

Bars

Answer 40

ridge of sand formed along a shore by the action of waves or current

Question 41

Cusps

Answer 41

shoreline formations made of various grades of sediment in an arc pattern, once one has been created it is SELF-SUSTAINING

Question 42

Stacks

Answer 42

needle shaped column resulting from the collapse of an arch

Question 43

Arches

Answer 43

hollowed out of a headland by the sea

Question 44

Dunes

Answer 44

act as a line of defense between tidal waters and land behind them. usually migrate inland due to wind

Question 45

Berms

Answer 45

flattish wave-deposited sediment platforms

Question 46

Backshore

Answer 46

upper part of the beach,

Question 47

Foreshore

Answer 47

permanently underwater, waves break and surface action is the greatest

Question 48

Barrier islands

Answer 48

long narrow sandbar build up in shallow offshore waters, can be far out at sea

Question 49

Lagoons

Answer 49

when and island isolates a body of water between itself and the mainland

Question 50

What are the components of a beach profile

Answer 50

dunes, backshore, high water-line, foreshore, offshore

Question 51

Be able to explain how atolls are formed

Answer 51

coral forms around a sinking island, lagoon is formed from island dropping, leaving the ring of coral

Question 52

Be able to delineate the approximate extent of glaciation in the U.S. during past ice ages

Answer 52

Mainly went down the Great Plains

Question 53

What is the predicted effect of polar ice cap and glacier melting on sea level?

Answer 53

it would increase

Question 54

How is the predicted effect of polar ice cap and glacier melting expected to effect world population?

Answer 54

it would decrease, killing people when sea level rises and limiting space for people to live by reducing land above sea level