Chapter 3 Flashcards
(124 cards)
1
Q
external processes
A
weathering, mass wasting, and erosion that occur at the Earth’s surface and powered by energy from the Sun
2
Q
weathering
A
physical/chemical breakdown of a rock
3
Q
mass wasting
A
movement of rock, soil, or weathered material
4
Q
erosion
A
physical removal of material by wind, water, ice
5
Q
mass wasting does not require a
A
transporting medium
6
Q
what produces stream valleys?
A
combination of mass wasting and running water
7
Q
types of mass wasting
A
slump, rockslides, debris flow, and earth flow (aka soil creep)
8
Q
slump and rockslides
A
move along surfaces of weaknesses (water seeps in)
9
Q
debris flow and earth flow
A
act like waters (water overwhelms drain basin)
10
Q
most rapid mass-wasting events occur in areas of:
A
rugged, geologically young mountains
11
Q
As a landscape ages, massive and rapid mass-wasting processed give way to
A
smaller, less dramatic downslope movements
12
Q
Controlling force of mass wasting
A
gravity
13
Q
trigger
A
event that initiates mass-wasting
14
Q
factors affecting mass wasting
A
water, vegetation, angle of repose, earthquakes, oversteepened slopes
15
Q
angle of repose
A
steepest angle of dry sediment before it slides
16
Q
Water is transported from one reservoir to another via the
A
hydrologic cycle
16
Q
biggest reservoir
A
ocean-97.2%
glaciers-2.15%
groundwater-groundwater .62%
all else-0.03%
17
Q
infiltration
A
water soaks into the ground
18
Q
runoff
A
surplus water flows over the surface into lakes and streams
19
Q
transpiration
A
water that soaks into ground is absorbed and released by plants into atmosphere
20
Q
water balance
A
volume that passes through each part of the cycle annually
21
Q
single most important agent sculpturing Earth’s land surface
A
immense volume of moving water
22
Q
amount of runoff depends on
A
intensity and duration of rainfall, amount of water in soil, nature of the surface material, slope of the land, extent and type of vegetation
22
Q
tiny channels
A
rills
23
rills meet and form
gullies
23
gullies meet and form
streams
24
streams meet and form
rivers
25
drainage basin
area of land that contributes water to a river
26
drainage divide
area of high elevation that separates basins
27
Mississippi River
largest drainage basin in North America
28
sediment production is located
in the headwater region of the river system
29
Stream flow is characterized as
laminar and turbulent
30
laminar
water flowing in smooth, straight-lined paths
31
turbulent
flow characterized by swirls and eddies
32
highest velocities in straight stretches
near center just below the surface
32
highest velocities in curved stream
shifts
33
The ability of a stream to erode and transport material depends on its
velocity
34
Factors that influence velocity in a stream
1-gradient
2-shape, size, roughness
3-volume of water flowing in channel
35
Where is the velocity of a river measured?
gauging station
36
Gauging station helps
calculate the river's discharge
37
discharge
volume of water per unit time
| m^3/s
38
gradient
the slope of a stream
39
the steeper the gradient,
the more energy available for streamflow
40
Smooth channel produces a more _____ flow, irregular channel produces _____
uniform, turbulence
41
intermittent streams
streams that exhibit flow only during wet periods
42
ephemeral streams
carry water only occasionally after a heavy rainstorm
43
A stream will flow from its
head/headwaters to its mouth
44
3 works of flowing water
1-erosion
2-transportation
3-deposition
45
erosion
wind, ice, and rain will dislodge soil and rock. rivers themselves can also erode floodplain/channel materials
46
load
material moved by the river
47
3 types of transportation
1-dissolved load
2-suspended load
3-bed load
48
dissolved load
ions in solution
smallest loaddO
Na, K, CO2
49
Does velocity have an effect on the streams ability to carry a dissolved load?
no
50
suspended load
particles actively carried by water's flow
varies with velocity
LARGEST LOAD
usually silt and clay
51
bed load
coarse material at the bed of the river
gravel, stones, etc.
may move by saltation (jump, roll, etc)
52
What determine's a stream's competence?
its velocity
53
Competence
maximum particle size a river can transport
54
capacity
maximum load of a stream
55
The greater the discharge, the greater the
stream's capacity
56
deposition
ultimately, stream loads are deposited when velocity decreases
57
alluvium
the material deposited by a stream bedrock channels
58
bedrock channels
which streams are actively cutting into solid rock
59
alluvial channels
bed and banks are primarily composed of unconsolidated sediment
64
braided channels
form where a large proportion of the stream's load consists of coarse material and the stream has a highly variable charge; wide and shallow
65
what type of loads are transported in meandering channels?
suspended loads
66
what type of loads are transported in braided channels?
bedloads
67
base level
limit to how deep a stream can erode
68
2 types of base level
ultimate base level and temporary base level
69
ultimate base level
sea level
70
temporary base level
lakes, resistant layers of rock, and main streams that act as base level for their tributaries
71
stream valley
consists of the channel AND terrain that directly contributes water to the stream
72
Sides of most valleys are shaped by a combination of
weathering, overland flow, mass wasting
73
2 types of stream valleys
narrow V shaped valleys and wide valleys with flat floors
74
most prominent features of V shaped valley
rapids and waterfalls
75
floodplain
increasingly broader, flat valley floor covered with alluvium
76
incised meanders
meanders that flow in steep, narrow valleys
77
How do incised meanders form?
Either base level dropped or land was uplifted.
78
delta
result of a stream entering a still body of water and its velocity drops abruptly
79
distributaries
formed by main channel dividing into several smaller ones
80
Distributaries carry water ____ from the main channel
away
81
natural levees
parallel channels on both banks
82
backswamps
marshes formed when water can't flow over the levee into the river
83
yazoo tributaries
stream that can't enter river because levees block the way
84
types of drainage patterns
dendritic, radial, rectangular, trellis
85
dendritic drainage patterns
forms where material is uniform, patterned determined by slope of the land
86
radial drainage patterns
streams diverge from central ares, develops on cone shaped land
87
rectangular drainage patterns
bedrock is criss-crossed in right angles
88
trellis drainage patterns
tributary streams are nearly parallel to one another
89
floods
most common and destructive natural hazards
90
when do floods occur?
when amount of precipitation exceed drainage capacity of the river
91
Flood control approaches
artificial levee, flood-control dams, channelization
92
artificial levees
earthen mounds built on banks of river to increase volume the channel can hold
93
flood-control dams
built to store floodwater and then let it out slowly
94
channelization
altering a stream to speed flow of water (building canals)
95
nonstructural approaches
zoning and relocation
96
zoning
move homes away from floodplain
97
relocation
force people to move
98
groundwater
precipitated water seeps through soil and rock to accumulate in the subsurface
99
groundwater's geologic roles
erosional agent, equalizer of stream flow
100
factors affecting groundwater volume and flow
porosity and permeability
101
porosity
volume of pores in a rock
102
permeability
interconnectedness of the pores
103
The deeper you go into the zone of saturation,
the greater the water pressure
104
springs
occur whenever the water table intersects Earth's surface and a natural outflow of groundwater results
105
aquifer
a geologic unit w/ high porosity and permeability; transfers and stores groundwater
(sands, gravels, sandstones, some limestone)
106
aquitard
impermeable layer that hinder ground-water flow (shales, clays, and crystalline rocks)
107
hot springs
6 to 9 degrees celcius warmer than annual air temperature
108
geysers
intermittent hot springs or fountains in which columns of water are ejected with great force at various intervals
109
where do geysers occur?
where extensive underground chambers exist within hot igneous rocks
110
well
a hole bored into the ground to reach the saturated zone
111
significant pumping of groundwater causes
drawdown and cone of depression
112
drawdown
lowering the local water table
113
artesian well
groundwater rises in a well above the level where it was initially encountered
114
Conditions that must exist for an artesian well
water must be confined to an inclined aquifer AND aquitards must be present to prevent the water from escaping
115
most caverns are created
at or just below water table in zone of saturation
116
dripstone
cave deposits
117
the deposition of dripstone is not possible unless
the caverns are above the water table
118
stalactites
hang from ceiling of the cavern
119
stalagmites
formations that develop on floor of cavern
120
column
forms when stalactites and stalagmites join
121
karst topography
landscapes that have been shaped by the dissolving power of groundwater
122
where do karst landscapes occur?
areas underlain by limestone
123
ways sinkholes for my
gradually over many years or suddenly when roof of a cavern collapses under its own weight
124
tower karst
landscape consists of steep-sided hills that rise abruptly from the ground, in tropical areas
