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Exam #3
Exam #3
144
Geology
Undergraduate 3
11/09/2014

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Cards

Term
What are the main differences between wind and running water?
Definition

less density

less viscosity

no confining channel

commonly more turbulent flow

Term
WHat are the three motion of particles?
Definition

Bed load

suspended load

saltation-jump

Term
What is the total load?
Definition
all three motion of particles together
Term
What is competence?
Definition
the largest particle that's observed moving
Term
WHat are the three erosional features?
Definition

1. deflation

2. desert placement

3. sand blasting

Term
What is deflation?
Definition

lowering of the existing surfaces

- wind blows fine particles

Term
What are the five things that happen during desert placement?
Definition

1. desert pavement formation begins with the wind blowing fne-grained materials into heterogeneous soil or sediment

2. during rainstorms, the fine, windblown sediments infilrate beneath the coarse layer of pebbles

3. Microbes living beneath the pebbles produce bubbles that help raise the pebbles & maintain their position at the surface 

4. Overtime, these processes lead to thickening of the dust accumulating beneath pebble layer

5. a continued supply of wind blown dust makes the deposit thicker

Term
What is sand blasting?
Definition

Wind fractured pebbles to ventifact 

- the side the wind is coming from will be polished and the opposite side will be rough

Term
Sand dunes are considered to be what kind of features?
Definition
depositional features
Term
Under what conditions do Sand Dunes form?
Definition

-availability of sand

-wide open area

-STRONG wind

-an obstacle (rock or vegetation)

Term
What happens during the early stage of sand dunes?
Definition
small sand drifts form in wind shadow
Term
What happens in the middle stage of sand dunes?
Definition
large but seperate form in wind shadow
Term
What happens in the final stage of sand dunes?
Definition
drifts coalsce into a dune
Term
How does a ripple or a sand dune advance?
Definition
by the movements of individual grains of sands
Term
What are the five types of sand dunes?
Definition

Barchans

Blowout dunes

Transverse Dune

Longitudinal Dunes

Star Dunes

Term
What sand dune is crescent shaped?
Definition
Barchans
Term
In a barchan dune the direction the horns of the crescent point mean what?
Definition
They point downwind
Term
Barchan dunes are the products of what?
Definition
limited sand supply and unidirectional winds
Term
Barchan dunes are usful to determine what?
Definition
the direction of the wind
Term
What are blowout dunes?
Definition
The reverse of barchans- THe slip face of a blow out ddone is convex downwind - shaped like a C if the wind is coming at it like <<<<< but is an opposite C is coming like <<<<
Term
What is a trasverse dune?
Definition
Long ridge oriented at right angles to the wind direction
Term
How to trasverse dunes form and where?
Definition
They form in regions where there is abundant sand and vegetation is absent- normally found around beaches
Term
What are longitudinal dunes?
Definition
long ridges of sand whose orientation is parallel to the wind direction
Term
What is needed for longitudinal dunes need to form?
Definition
moderate sand supply, a rough pavement, and winds that are always in the same general direction
Term
What are star dunes?
Definition
multiple changes of direction
Term
Where are star dunes found?
Definition
In Africa in the Sahara Desert
Term
What are the three types of deserts?
Definition

Hot Deserts

Temperate Zone Deserts

Cold Deserts

Term
What is an example of a Hot Desert?
Definition
Sahara Desert, Australian desert, Kalahari desert
Term
What are the characteristics of a Hot Desert?
Definition
Typical Deserts- 0-30degrees Nother & 30-50 degrees south
Term
What are examples of Temperate Zone Deserts?
Definition
Great Basin, Gobi,and Mojawe
Term
What are the reasons for the Temperate Zone deserts?
Definition

Rain shadow

area is far away from water

orographic effect

Term
What are the latitude and longitude regions for the Temperate Zone desert?
Definition
30-50 degrees nother and 30-50 degrees south
Term
What are the latitude and longitude of the cold deserts?
Definition
50-90 degrees north and 80-90 degrees south
Term
What are the five desert characteristics?
Definition

physical weathering is predominant

thin soil

deflation/desert pavement/ ventifacts/dunes

desert varnish- reddish brown coating

suspended sediments

Term
What are the two kinds of glaciers?
Definition
valley glaciers and continential glaciers
Term
What are valley glaciers?
Definition
glaciers that move through valleys
Term
What are continental glaciers?
Definition
large piece of ice moving over the land (continents)- Greenland is an example
Term

What steps does a glacier go through to form and how long does it take to form?

 

 

Definition

snow- 90% air

granular ice- 50% air

Firn- 20-30% air

glacier- 20% air as bubbles

 

It takes 15-20 years to form

Term
What happens it ablation is higher than accumulation?
Definition
Ice front recedes
Term
What happens is accumulation and ablation are equal?
Definition
Ice front remains in the same position
Term
What happens if acculamation is higher than ablation?
Definition
Snow fall, snow turing to ice
Term
What happens if ablation is dominant?
Definition
sublimimation
Term
What is ablation and what are the three ways it can happen?
Definition

loosing of ice

1. direct melting

2. iceburg caluing

3. sublimation- solid goes to gas

Term
How long does it take for glaciers to form?
Definition
15-20 years
Term
Valley glaciers are also known as what...
Definition
Alpine glaciers
Term
Alpine Mountains are an example of what?
Definition
Valley glaciers
Term
What are the three mechanisms of glacial flow?
Definition

plastic flow

basal flow

glacial surge

Term
What is plastic flow?
Definition
individual ice crystals move
Term
What is basal slip?
Definition

-whole thing moves as a unit

-slight melting at the base

-thin film of water

 

 

Term
Where is basal slip common?
Definition
dominates in temperate regions where pressure of overlying ice melts water at glacier base
Term
What is glacial surge?
Definition
very rapid movement of glacier
Term
When do crevasses form?
Definition
where a glacier moves over steps in bed topography and where is curves around topographic
Term
How to valley glaciers typically move?
Definition
by plastic flow
Term
What are all of the glacier features?
Definition

-U shaped valley

-Stration

-Hanging Valley

-Cirque

-Horn

-Tarn

-Fjond

-Arete

Term
What is the area between two valleys called?
Definition
a divide
Term
When do cirque and aretes form?
Definition
During glaciation
Term
How is a U shaped valley created?
Definition
The glacier moving down from its cirque
Term
How are hanging valleys created?
Definition
WHen ice melts and retreats and tributary valleys are left as hanging valleys
Term
How are hanging valleys marked?
Definition
by waterfalls
Term
What is a cirque?
Definition
the head of a glacial valley with nearly vertical upper walls and a flat or hollowed out base
Term
If a cirque is filled with water what is it called?
Definition
cirque lake
Term
What is a tarn?
Definition
series of small lakes forming in the valley
Term
How do tarns form?
Definition
form because when glaciers melt they dont do it un uniform so the ice chunks melt at different times
Term
What is a fjord?
Definition
a U shaped valley occupied by an arm of the sea
Term
What is till?
Definition
Heterogeneous mix of sediments deposited during direct melting of ice
Term
What is outwash?
Definition
sediments deposited by melted water. sorted sediments because it is homogeneous
Term
What are the depositional valley glacier features?
Definition

Ground Moraine

Lateral Moraine

Media Moraine

End Moraine

Term
What is the ground moraine?
Definition
if the till is deposited at the end of the valley
Term
What is lateral moraine?
Definition
Deposited along the side of the valley
Term
What is the media morine?
Definition
deposits in the middle
Term
What is the end moraine?
Definition
at the edge of the glacier
Term
What are the features of continental glaciers?
Definition

-End Moraine

-Kettle Lake

-Roaches Mountanees

-Drumlin

-Kame

-Varue

-Esker

Term
What is End Moraine?
Definition
See the till at teach belt
Term
What are the two types of end moraine for continental glaciers?
Definition

Terminal Moraine

Recessional moraine

Term
What is terminal moraine?
Definition
terminal moraine is the first moraine belt
Term
What is recessional moraine?
Definition
linked to the terminal moraine- all of the other moraine belts
Term
What are kettle lakes?
Definition
blocks of ice that take a longer time to melt
Term
What happens during Ice melting?
Definition
A large block of wasting ice is isolated from the main ice mass on an outwash plain surrounded by outwash sediments
Term
What happens after complete deglaciation?
Definition
a kettle remains after the ice block melts; a lake forms if the kettly lake base is below the water table
Term
What are eskers?
Definition
ice gone and see huge pills of sediment where ice was before
Term
What are drumlins?
Definition

hill of till deposits- accumulation of till deposits

parallel to flow

Term
What is Kame?
Definition
deposits of outwash, right angles, perpendicular to flow
Term
What is outwash?
Definition
sorted sand and gravel
Term
Which two features are opposites?
Definition
Drumlin and Roach Mountains
Term
What are Roach Mountains?
Definition
Bed rock high- due to ice it becomes a gentle slope on the side that the ice came from
Term
What are Varues?
Definition

Rythemic deposits of coarse and find sediments

 

f

c

f

c

 

Term
Interglacial =
Definition
course
Term
Glacial =
Definition
fines
Term
What are the two causes of glaciation?
Definition
Plate tectonics and Astronomical
Term
What is astronomical?
Definition
distance from the sun- high eccentricity & low eccentricity
Term
What is high eccentricity?
Definition
furthest distance frmo the sun- it's an oval
Term
What is low eccentricity?
Definition
lower distance from the sun- circle
Term
How long does astronomical take?
Definition
100,000 year cycle
Term
What are the two types of rock?
Definition

Ductile- soft

Brittle- strong

Term
What are the three types of forces?
Definition

Tensional <-----> (pull apart)

Compressive ----><----- (push together)

Shearing- sliding past each other

Term
What two characteristics do folds need in order to be considered a fold?
Definition
compressive and ductile
Term
What does fault need in order to be considered a fault?
Definition
Brittle and all of the forces (tensional, compressive, shearing)
Term
What is a strike?
Definition
the way the fold is going- where it is striking
Term
What is dip?
Definition
which way the limb is going
Term
A horizontal fold has a...
Definition
horizontial fold axis
Term
A plunging fold has an axis at a.....
Definition
angle to the horizontial
Term
Which way do anticlines fold?
Definition
upward
Term
Which way to synclines fold?
Definition
downward
Term
What do assymetrical folds have?
Definition
have one imb that dips more steeply than the other
Term
What do symmetrical folds have?
Definition
have limbs that dip symmetrically from the axial plane
Term
What is an overturned fold?
Definition
have limbs that dip in the same direction, but one limb has been tilted beyond verticle
Term
What are the three kinds of faults?
Definition

1. Dip slip

2. strike slip

3. oblique slip

Term
What is a hanging wall?
Definition
goes down relative to the footwall
Term
What causes normal faulting?
Definition
caused by tensional forces that stretch a rock and tend to pull it apart
Term
What are the three types of dip slip faulting?
Definition

Normal faulting

reverse faulting

a thrust faulting

Term
What causes a reverse fault?
Definition
by compressive forces that squeeze and shorten a rock
Term
What is a thrust fault?
Definition
reverse fault with a shallow-dipping fault plane
Term
What is strike slip fault?
Definition

Left lateral- deposit the left one

right lateral- deposit the right one

Term
What is oblique slip faulting?
Definition
caused by a combination of forces in this case left- lateral/ shearing with tension
Term
What are the four evidence of faulting?
Definition

1. offset in rock layers

2. lithological change- walking along and seeing rock change

3. sudden change in age

4. sudden change in topography

Term
What is the wave length?
Definition
from crest to crest
Term
What is the wave heigth?
Definition
from crest to trough
Term
What is the wave equation?
Definition
v=l/t
Term
What are ocean waves characteristics?
Definition

1.waves travel but water says in the same place

2. When the bottom shallows to about one half the wave length, th wave slows, its wave length decreases

3. as waves approach the shore, they become too steep to support themseles and breaking the surf zone, running up with beach in a swash

 

Term
What is wave refraction?
Definition
start at angle and become parallel to the shoreline
Term
WHat is the wave length?
Definition
distance between crust and trough
Term
If I compare two shore lines- one at an angle and one that is straight up and down which one will erode faster and why?
Definition
stright one because the breakers are forming closer to the shoreline
Term
What is a solar day?
Definition
24 hours
Term
What is a lunar day?
Definition
24 hours and fifty minutes
Term
What is the tidal force?
Definition
gravitational force between the moon and the earth
Term
How often is there a tide?
Definition
12 hours and 25 minutes
Term
What is a spring tide?
Definition
when all in a line (full moon and new moon) That's when we see highest possible tide the sun adds to it with them all lined up
Term
What is a neap tide?
Definition

-low

1st &3rd quarter

when solar tide is in oposing force-not adding to the tide

Term
What are the six steps of wave refraction?
Definition

1. fast traveling wave approaches deep water

2. part of the wave closest to the beach slows causing the line of waves to refract toward the beach

3. waves bend toward the projecting part of the shore which increases the wave impact on the headland

4. paths of crest diverge, decreasing the wave impact on the beach

5. wave approaches the shore at an angle causing a long shore current

long shore drift results from movement of sand particles by swash and backwash

Term
How does water and sand travel?
Definition
in a zig zag
Term
What is a stack?
Definition
left behind piece of rock that will be eroded in the future- in middle of waterr
Term
WHat causes headland to be hit with the highest wave velosity?
Definition
wave refraction
Term
What is a sea arch?
Definition
becomes point of maximum erosion
Term
What are the erosional features for oceans?
Definition

stacks

sea arch

wave cut terrace

tidal valley

Term
WHat are the dispositional features?
Definition

spit

tidal flat

atoll

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