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Geology 120 > Test 3 > Flashcards

Test 3 Flashcards

1
Q

Transpiration

A

Process by which moisture is carried through plants from roots to small pores on the other side of leaves where pit changes to vapor and is released in the atmosphere

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2
Q

Hydrologic cycle

A 
Precipitation
Infiltration
Run off
Subsurface flow
Transpiration
Evaporation (from rivers, lakes, ocean)
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3
Q

Rivers

A

Water contained within a channel

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4
Q

Hydrology

A

The science of try and streams and rivers in the hydroloc cycle

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5
Q

Drain basin

A

Area drained by a single river (or system)
-where water will flow after rain, into what river
-based on the biggest river all other rivers flow into
—we ar cape fear river basin

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6
Q

Basins are separated by

A

Ridges called divides

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7
Q

Continental divide

A

Separation of water flowing to the Pacific Ocean vs the Atlantic Ocean
Pacific west
Atlantic east

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8
Q

Watersheds

A

The smaller areas river basins are divided into

-specific river that will eventually flow into the bigger river which is what the river basin is based off of

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9
Q

Riparian

A

Areas around and affected by river including habitat
-a minimum width of riparian habitat (including vegetation) is crucial to provide ecosystem services
—for the river to provide everything it should it needs a minimum width of riparian habitat so you can’t developed too close to a river
—-varies depending on type of stream but generally minimum of 100 feet

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10
Q

Floodplain

A

Area by a river that periodically floods
-can have more than one
—ie water street downtown
*not on the coast, inland

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11
Q

Alluvium

A

Sediments deposited by rivers

—finer size sediment particles

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12
Q

Formation of drainage networks

A

Stream flow begins as water is added to the surface (snow melt, precipitation, etc)

  • steam flow begins as moving “sheetwash”
  • sheetwash erosion creates tiny rills (channels)
  • tributaries form
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13
Q

Sheetwash

A

Thin surface layer of water that moves down slope, eroding

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14
Q

Rills

A

Rills coalesce and deepen into tributary

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15
Q

How/when rivers/channels flow based on location

A

Ephemeral-above water table: don’t flow all year

Permanent- at or below the water table: flow all year

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16
Q

How is river flow based on geology

A

Bedrock: straight, found closer to the head (source) or steeper elevations
Alluvial:
-braided: broad, gravel, shallow, weave in and out of each other; often associated w glaciers
-meandering: deep, piedmont, squiggly like, found in coastal areas
*some streams can be more than one if it for example flows from the mountains to the coast

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17
Q

Straight (bedrock) river

A

Associated with mountainous river portions - closer to the head
— “young” stream stage

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18
Q

Braided (alluvial)

A

Form where channels are choked by sediment

  • gravel bars are unstable, rapidly forming, and being eroded away
  • flow occupies multiple channels across a valley
  • often sssociated w glaciers (but not always)
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19
Q

Meandering rivers (braided rivers)

A

Head-source of stream
Mouth-outlet of the river (where it empties)
Cut bank-where erosion occurs (higher velocity)
Point bars-deposition occurs (lower velocity)
Natural levees-bank deposition
Oxbow lakes-abandoned loops (former remnants of the river)

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20
Q

River components (in most rivers)

A

Pools-deep pools beneath banks (usually higher velocity w large rocks or something surrounding it)
Riffles-shallow, course gravel (higher in oxygen than pool, higher number of organisms because of this)
-important habitats

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21
Q

River process controls

A
  1. Discharge
  2. Gradient
  3. Geology
  4. Sediment load
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22
Q

Discharge in a river

A

Volume of water that’s passing by a certain point in a given unit of time
-mostly cubic ft per second or cubic meters per second
Equation=(depth x width) x velocity
—velocity is not uniform throughout steam (highest in the center, lowest towards the banks bc as the water is coming into contact w sediment along side the stream it’s creating friction and slowing down the flow)
—wider and shallower more friction, narrow and deep less friction)

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23
Q

Gradient in rivers

A

Slope=rise/run
Longitudinal profile = change in evolution
Thalweg- profile that connects points of highest stream velocity
Gradient decreases w distance, works towards base level (flat area)

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24
Q

Sediment load

A

Materials moved by steams in the sediment loads: three types

  1. Dissolved load: ions that have been dissolved into the water from wether of minerals (smallest)
  2. Suspended load: fine particles like clay and silt that are carried in the flow of water but not dissolved, just light enough to be carried
  3. Bed load: large particles roll. Slide and bounce along (largest) ie boulders
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25
Q

Competence vs capacity

A

Competence: max size transported
Capacity: max load transported

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26
Q

Geology in river process

A

Igneous and metamorphic: younger. Straighter streams

Sedimentary rock: easily stored, meandering and alluvium streams

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27
Q

How do the four factors interact

A

Higher gradient means velocity will increase as will the sediment load (capacity) and discharge
Change the geology and river may straighten or start meandering and discharge more or less

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28
Q

Rapids

A

Turbulent water, reflect geological control
Represents:
-flow over resistant bedrock steps or over large coasts
-abrupt narrowing of channel
-sudden increase in gradient

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29
Q

What’re rapids classified as

A

Classes 3-4 are white water

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30
Q

Waterfalls

A

Streams that cascade or free fall
-waterfall energy scours base of waterfall and may cause erosion imitating collapse of overlaying rocks
—in nc the “fall line” represents change from hard rock into softer sedimentary rocks and can sometimes result in a water fall

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31
Q

Deltas

A

Deltas form when a stream enters standing water

  • current slows and loses competence (can’t carry larger particles) sediments drop out and settle
  • stream divide into a fan of small distributaries (opposite of tributary)
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32
Q

Landscape evolution

A 
Steam flow is the cause of most landscape changes
Time 1. Young stream
-steam cuts into former surface 
-straight streams
-good drainage 
Time 2. 
-meanders begin down strea
-valleys widen, hill erodes
Time 3. Mature
-landscape eroded to base level
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33
Q

Dynamic equilibrium

A

Base level achieved

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34
Q

Forest to agriculture

A

Trees removed, roots support for soil gone, more erosion

  • river capacity increases: deposition increases, slope increases
  • velocity increases until river can carry new sediment load
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35
Q

Agriculture to forest local example

A

Early on (1800-1900s) the piedmont was converted to agriculture
After 1930s some areas converted back to forest land
Less sediment-stream eroded more-deepening

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36
Q

Wetland

A

Land areas inundated of ground saturated more than a few days every year and composed of:
Swamps: dominated by trees and shrubs
Marshes: frequently to continuously inundated w water , not dominated by trees or shrubs
Bogs: accumulated peat deposit (peat from dead vegetation)
Prairie potholes: small mash like ponds

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37
Q

Wetland benefits

A
  1. Buffers for inland areas from coastal erosion and storms
  2. Act as natural filters (trapping sediment/pollutant)
  3. Freshwater wetlands absorb excess water (reduce flooding)
  4. Special nutrient rich ecosystems
  5. Freshwater wetlands are commonly groundwater recharge zones
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38
Q

Concerns of wetlands

A
  1. Half of all us wetlands lost in last 200 years
  2. 90% of these post wetlands are freshwater (drained for urbanization)
    - drained got agriculture
    - drained for urbanization
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39
Q

Places earths water is in and how much

A 
70% earths surface
Including
Rivers and flooding
Groundwater
Coastal
Glaciers
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40
Q

How does water break down by a source

A

Oceans 97.2% residing for 1000s years
Glaciers2.15% residing for 10000+ years
Groundwater (and everything else ) residing for days to 1000s years

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41
Q

What falls under all else in ground water

A

Lakes or freshwater .0090% time there 10s year
Atmosphere .0010% there for 9 days
Rivers and streams .0001 two weeks there

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42
Q

Why are rivers crucial for humans

A 
Drinking water
Transportation
Waste disposal
Recreation
Commerce
Irrigation
Energy
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43
Q

Reasons river are Important

A

Crucial for humans
Stream runoff causes flooding (lives and property)
River stream run off is an important geological agent

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44
Q

Why is stream runoff an important geological agent

A

Flowing water erodes,transports, and deposites sediments which
Sculpt landscapes and
Transfer mass from continents to water basins
(Earth perhaps the only planet in the solar system w flowing water)

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45
Q

Stream

A

Smaller river

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46
Q

Tributaries

A

Streams that are part of a larger river

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47
Q

Groundwater what percent

A

> .30%

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48
Q

Groundwater

A

Vadose zone/unsaturated zone
Water table
Saturated zone

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49
Q

Sedimentary properties affecting groundwater flow

A 
Porosity 
Permeability
-fine sediments low porosity
-Note: high porosity does not mean high permeability 
—clay
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50
Q

Hydraulic properties

A

Hydraulic gradient
Groundwater flows from HIGH pressure to LOW pressure
-high elevation to low elevation

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51
Q

Recharge zone

A

Groundwater infiltrations start at

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52
Q

Influent streams

A

Streams above the water table do not flow all yer long,
-usually lose water to water table
(Ephemeral streams)

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53
Q

Effluent streams

A

Streams below the water table, that flow layer long

Permanent perennial stream

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54
Q

Aquifer

A

Porous and permeable layer of rock

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55
Q

Aquiclude

A

NonPorous and non permeable layer of rock

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56
Q

Confined aquifer

A

Surrounds by acquiluids

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57
Q

Unconfined aquifer

A

Open to the environment

58
Q

Hydronic conductivity

A

Another word for permeability which depends on a variety of sedimentary factors
-size
-rock type
Sedimentary: higher porosity generally
Shist: higher porosity generally (bc can fracture easily)

59
Q

Hydrologic gradient

A

Creates a pressure surface (also called the potentiometric surface)

60
Q

Artesian Wells

A

Wells that produce below the pressure surface do not need to be pumped

61
Q

Wells above the surface must have water

A

Pumped

62
Q

Piezometers

A

Instruments that measure groundwater pressure (head)

63
Q

Cones of depression

A

Wells,often many wells, create this around where the water table intersects the wall
—overtime the water table can be depleted by this

64
Q

Overdrafts

A

I many instances groundwater is pulled out faster than is recharge

65
Q

How many Americans use groundwater for drinking water

A

Overdrafts

66
Q

Overdrafts cause

A

Subsidence and saltwater intrusion

67
Q

Why has water usage gone down since 1980’s

A

Better management, conservation, changing usage

68
Q

Since 1980’s uses of water

A

Industrial use and rural domestic and livestock used for less

69
Q

Ocean water versus consumable water

A

Ocean 3.5% salt

Potable water .05% salt

70
Q

Desalination drawbacks

A

Costs of desalination are falling but are still prohibitive
Costs of transporting fresh water may be less than local desalination
May prices about one million ft cubed of freshwater

71
Q

Water pollution in nc

A

-One pig produces two tons of waste per year… and we have 2-10 mil pigs! Usually pig farms in flood plains
manure and urine palaces in four meter deep unlined lagoons
—June 1995 25 million gallons of lagoon waste flood into the New River
—hurricane Floyd in 1999 250 million gallons of pig waste was flooded into rivers
—-bodies of animals were buried and decaying bacteria entered ground water

72
Q

What happens when water gets polluted

A

Organic matter (dead plants or animals) consumed by bacteria (microorganisms)

  • bacteria needs oxygen to survive (aerobic bacteria)
  • bacteria can remove oxygen from water- may kill fish, etc
73
Q

How do we measure amount of bacteria proceeds in water during pollution

A

Biochemical oxygen demand (BOD)
-is a measure of the amount of oxygen indication level of havgrtialtovrss*****
—high BOD = high level of decaying organic matter

74
Q

Why else is pollution scary

A

Pathogenic (disease causing) bacteria
-May be aerobic (oxygen breathing) or anaerobic (without oxygen)
—cholera, typhoid infections, dysentery and hepatitis
—monitored by tracking levels of fecal coliform bacteria

75
Q

E. coli

A

Causes illness sand death

  • from cow manure to public water supply during flooding
  • contaminated meat
76
Q

Nutrient pollution from human activity

A

Phosphorus and nitrogen
-fertilizers, detergents, sewage refuse
-part of the n-p-k rating seen on fertilizers
—forest land low concentrations
—agriculture/urban high concentrations
High amounts of p and n in water = cultural eutrophication
—increase in plant life especially algae
—like bacteria, removes oxygen may cover the lake, blocking sunlight

77
Q

Oil petroleum spills

A

Major pollution
-match 1989 Exxon Valdez (250,000 barrels or 11 million gallons)
-bp deep water horizon oil spill 2010
—4.9 mil barrels or 2206 million gallons
—still seeping slightly
Comparison: Exxon Valdez releases just 5% of the oil bp spill

78
Q

Toxic substances

A

Hazardous chemicals
-example mtbe (methyl tertbutyl ether) and trichloroethylene (tce)- gasoline additive added to increase oxygen in gas and reduce co emissions
—very sullenly often detected in ground water
—mtbe contaminated groundwater in Santa Monica ca caused them to stop pumping, eliminating 50% of their total drinking water
Heavy metals
-lead, cadmium, zinc, mercury
—deposited in sediments (if in flood plains may dissolve in water and get into plants and animals)

79
Q

Mercury as a pollution

A

Natural and manmade sources
—volcanic eruptions, erosion of mercury deposits (minerals), burning coal, waste incineration, processing of metals
Hg joins with other metals forming amalgams often used to concentrate gold
-such processes may allow into the atmosphere and into aquatic systems
-methylation from bacterial activity converts Hg2+ to methylmecury which is v toxic
-biomagnification: as methyl mevity makes its way through the good chain amount increases as size increases

80
Q

Gen-X

A

Hydrological units with detectable PFASs

81
Q

Groundwater contamination

A

There are many sources of groundwater contamination

  1. Sanitary waste: failing septic system or animal feedlot runoff (remember hogs)
  2. Agricultural wastes: fertilizers and pesticides
  3. Toxic chemicals: industrial wastes: paints and thinners, and degreasers and solvents
    - petroleum storage: underground storage tanks
82
Q

Problem with contamination groundwater

A

Pollution is often not recognized until damage occurs

Cleanup is slow,expensive,and limited

83
Q

Types of groundwater treatment

A

Treat and pump
Most common treatment of groundwater contamination: pump and treat
-remove source, put in extraction well, pump bad stuff out of ground and put it somewhere less armful
2. Bioremediation utilizes bacteria to clean groundwater- or coastal waters

84
Q

Clean water act 1972

A

The purpose was to maintain the biological, physical and chemical integrity of the nations water, which includes: rivers, streams, lakes, and wetlands
-the goal was by 1983 to make all the nations rivers drinkable and swimmable and to achieve zero discharge from point source pollution

85
Q

Flooding

A

Idk was there

86
Q

Flood results exacerbated by

A 
Torrential rains
Saturated soils as a result of prior rainfall
Urbanization
Topography
Biology (vegetation buffers)
Snowmelt (not around here)
87
Q

Flash flood

A

Higher elevation
Rapid heavy rainfall
Short duration and lag time
Ie Las Vegas

88
Q

Downstream floods

A

Wide area
Longer rainfall
Longer lag time
Ie hurricane Florence

89
Q

Flood stats

A

Most rivers have a stream gage to measure discharge

  • many have over 100 years of flood data
  • understanding flooding history of a river can help us predict future flooding
90
Q

Discharge formula

A

Discharge=Area of river channel x velocity

D=AxV

91
Q

Magnitude measures

A

Place specific

Put the discharges in decreasing order and number one to whatever

92
Q

Recurrence interval and probability

A

R=(N+1)/M

Probability is 1/R

93
Q

How does discharge relate to recurrence interval

A

More extreme, less frequently

Less extreme, more frequently

94
Q

Good estimation rule

A

You can only estimate twice the number of years on record

95
Q

Calorie

A

The amount of energy required to raise the temperature of one gram of water one degree Celsius

96
Q

Water cycle through the states of matter

A
  1. Solid—> melts(absorbs 80 calories)—>liquid»evaporation(absorbs 600 calories)>gas
  2. Solid>sublimation(absorbs 680 calories)>gas
  3. Gas>condensation (release 600 cal)>liquid>freeze(release 80 cal)>solid
  4. Gas>deposition (loses 680 calories)>solid
97
Q

Meteorology

A

Study of the atmosphere and the phenomena therein

-term. Coined in 340 bc by Aristotle

98
Q

Wether

A

The state of the atmosphere at any particular time and place

99
Q

Climate

A

A generalization of weather for an area, the “sum of all statistical weather info” NOT just an average
—old phrase: “climate is what you expect, weather is what you get”

100
Q

Wilmington climate

A

Car

Humid subtropical

101
Q

Atmospheric hazards

A 
Thunderstorms
Hurricanes
Tornadoes
Blizzards
Hailstorms 
FreeIng rain
Heat waves
102
Q

What is atmosphere

A

The envelope of gases surrounding the earth or another planet

103
Q

The atmosphere to scale

A

Thickeners of atmosphere: 100 km

Wilmington to Raleigh is 215 kilometers, aka two thickness of the atmosphere

104
Q

Four most dominant gases in the atmosphere

A
  1. Nitrogen 78.084%
  2. Oxygen 20.946%
  3. Argon .934%
  4. Carbon dioxide .036%
105
Q

Atmospheric pressure

A

Simply the weight of the air above

106
Q

Gravity affect on earth (atmospheric pressure)

A
  • gravity pulls air molecules closer to earth

- molecules of different masses are affected by gravity different

107
Q

Air pressure increasing or decreasing as you leave earth

A

Air pressure decreases as you leave earth

108
Q

Why does the air pressure decrease as you go up in altitude or increase as you scuba dive?

A

Fewer air molecules = lower density = low air pressure

More air molecules = higher density = higher air pressure

109
Q

Temperature trend through atmospheric layers

A

Sum of all things sign, backwards 3

110
Q

Troposphere

A
  • Extends from the surface to about 18km
  • Thickeners varies: thicker in tropics vs play region
  • Home of the vast majority of weather and life on earth
  • Temperatures decrease with altitude
  • ends at tropopause
111
Q

Tropopause

A

Temperature inversion after troposphere, it gets warmer instead of colder as you go up

112
Q

Stratosphere

A
  • starts at tropopause
  • extends from 18-50 km
  • temps increase with altitude
  • home of ozone layer
  • ends at strotopause
113
Q

Stratopause

A

Another temp inversion (gets colder higher elevation)

Ends stratopause and starts mesosphere

114
Q

Mesosphere

A

Starts at stratopause

  • extends 50-80 km
  • contains coldest portion of the atmosphere average inn -90 degrees calculus
  • ends with mesopause
115
Q

Thermosphere

A

Starts at mesopause

  • outermost portion of the atmosphere, everything greater than 80 km
  • upper limit (not well defined) of the thermosphere is called the Thermopause
  • very hot at the thermopause
116
Q

Why is it so hot in the thermopause if so cold in outer space?

A

Due to absorption of shortwave, high emerge solar radiation

117
Q

Thermopause

A

Moves in response to solar activity (500-1000 km)

118
Q

Notice:

Temp decreases in the troposphere

A

Simple decrease in the density of air molecules

119
Q

Notice: temp in crease in the stratosphere

A

Presence of o3 molecules absorbing uv radiation

120
Q

Notice: temp decreases (to lowest point) in mesosphere

A

Less o3 and reduced density of air molecules

121
Q

Notice: temp increase in the thermosphere

A

Absorption of short wave solar radiation by N and O

122
Q

What generates weather

A

How much solar energy we receive depend on the location, time of day, and season of the year so as a result the earth is heated unequally and this reduces winds and currents and eventually weather

123
Q

Primary earth motions

A
  1. Rotation
    -earth spins on its own axis every 24 hours, day night cycles
    -one half of the circle is lit by the sun at any one time (circle of illumination)
  2. Revolution (around the sun)
    -counterclockwise once every 365.25 days
    —determines seasons
    -follows an elliptical path within the plane of the elliptical
124
Q

Plane of the elliptical

A

Two dimensional surface that divides the earth and sun into two equal halves at all locations in the earths orbit

125
Q

Aphelion and perihelion

A

Aphelion: July 4th, furtherest point from the sun
Perihelion: January 3, closes point to the sun

126
Q

Important dates and latitudes

A

Equinox: sun vertical at equator, March 21-22 and September 22-23
Solstice: latitude 23.5 N (June 21-22)/S (December 21-22)

127
Q

Air mass

A

Two types (>1600 km2) stays over the scourge region for an extended period and takes on the characteristics of the source region

128
Q

Two types of air masses

A
  1. Cold (polar or p), warm (tropical or t), or very cold (arctic or a)
  2. Dry (continental or c) or humid (maritime or m)
129
Q

Frontal weather

A

Narrow zone of transition between air masses that differ in density
—density due to temp and humidity contrasts

130
Q

What happens when air masses meet at fronts

A

The folder, denser air forces the water, less dense air to rise
-this induces adianatoc cooling (decreasing pressure) and often cloud-precipitation development
The slope of the front influence the types of clouds that form
1. Warm front: v shallow slopes
2. Cold fronts: much steeper slopes

131
Q

Three types of fronts

A
  1. Warm front
  2. Cold front
  3. Occluded front
132
Q

Warm front

A

Just ahead of the front, steady precipitation usually gives way to drizzle and sometime frontal fog

  • if advancing war air is unstable or conditionally sunstanle, more vigorous uplift can occur with thunderstorms embedded in the overrunning zone
  • shallow tong
  • red semicircles
133
Q

Cold front

A

The slope o a cold front is much steeper than the slope on a warm front

  • upLift is confined to narrow area at or near the fold fronts leading edge
  • if the warm air is unstable, thunderstorms may form and a squall line (line of t storms) can develop
  • if the warm air is relatively stable, nimbostratus and altostratus clouds may form
  • blue pyramids
134
Q

Occluded font

A
  1. Cold type
    - air behind cold front colder than cool air ahead of warm front
    - like a cold front at the surface
  2. Warm type
    - air behind cold front is not as cold as the air ahead of the warm front
    - like warm front at the surface
135
Q

Stats on t storms

A

2000 thunderstorms at any moment
45000 every day
16 mil annually

136
Q

What is a thunderstorm

A

Instead of winds rotating around the center, t storms are composed on updrafts and dowmdrafts (somewhat)

  • short lived
  • accompanied by lightening and thunder
  • composed of a single cumulonimbus cloud or clusters of cumulonimbus clouds covering a large area
137
Q

Two types of t storms

A
  1. Air mass thunderstorm
    -form as a result of the unequal heating of the earth
    —typically a result of warm humid moist tropical air masses coming up the Gulf of Mexico
  2. Severe thunderstorms
138
Q

Three stages of development of thunderstorms

A
  1. Cumulus stage : sucks up rain and humidity
  2. Mature stage :sucks hot air up while raining down cold air
  3. Dissipating stage:hot air spreads out up top and cold air is released as a light rain
139
Q

Tornados

A

Local storm of short duration (most small tornadoes last 3 minutes or less)
-in touch with the ground can be up to 2.5 miles wide and produce winds topping 300 mph
Intense pressure differences, Drop of 100 mb was recorded by a tornado in 2003 (less than the storm it formed from

140
Q

Tornado shape

A

Also called Twisters or cyclones and take shape of a vortex
-some tornados are composed of several vortices called suction votices that orbit the center of the tornado
—multiple vortex tornados

141
Q

Tornado formation

A
  1. Supercell thunderstorm with strong vertical wind shear (both speed and direction)
    - weaker winds lower tot he ground with stronger winds aloft
  2. This sheer causes air to rotate about a horizontal axis in a rolling motion
  3. 295( strong updrafts this ruling motopn ca he pushed vertically forming a mesocyclone
    - updrafts draw humid rain cooled air in the system that (expands) condenses at a lower altitude forming a wall cloud
  4. As the mesocyclone narrows it spins faster and faster eventually extending down towards surface as a tornado
    - the spinning lowers the temp usually below the dew point causing a dark ominous cloud to form - picking up dust and debris (what we see as a tornado)
142
Q

Tornado intensity

A

Measured by the amount of damage done and the wind speed achieved
—the enhanced Fujita scale (EF0-EF5)

Geology 120 (4 decks)

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