MIDTERM 2 Flashcards
1
Q
types of cones
A
shield
composite
lava domes
cinder cones
2
Q
shield volcano and exmaple
A
shallow sloping sides formed by lava flows of low viscosity
Mauna Kea
3
Q
basaltic magmas
A
form shield volcanoes of lava flows from fissures
4
Q
spatter cone
A
small, steep sided cone built by lava splattering out of a vent
5
Q
pillow basalts
A
pillow shaped rounded blobs, each blob squeezed out like toothpaste
most form at mid oceanic ridges
6
Q
geomorphology
A
study of landforms (origin, evolution, form and spatial distribution)
7
Q
denudation and what does it do?
A
wearing away and removing rock
lowers continental surfaces
8
Q
5 denudation processes
A
weathering
mass movement
erosion
transportation
deposition
9
Q
weathering
A
all processes that cause rock to disintegrate physically and decompose chemically at earths surface
occurs in situ (in place)
10
Q
regolith
A
unconsolidated/decomposed rock
11
Q
what creates regolith?
A
weathering
12
Q
where does physical/mechanical disintegration predominate?
A
dry-cold climates
13
Q
where does chemical weathering predominate?
A
warm-wet climates
14
Q
chemical weathering
A
changes to chemical structure of minerals that compose rock
15
Q
7 factors that influence weathering
A
rock type
jointing
water
climate
slope orientation
vegetation
time
16
Q
7 types of physical/mechanical weathering
A
exfoliation
frost action
biomechanical
crystal growth
thermal expansion
freeze thaw
salt wedging
17
Q
exfoliation (physical)
A
pressure release jointing
igneous/metamorphic rock formed under great heat/pressure deep underground
pressure forces grains together reducing volume, reduced pressure forces grains apart increasing volume
pressure reduced = rock expands/breaks
18
Q
frost action (physical)
A
water fills pores/cracks in rocks
when water expands by 9% in volume it cracks rock
19
Q
what creates talus?
A
frost action/wedging
20
Q
biomechanical (physical)
A
plant growth - growth of roots and trees into rocks produce great pressure that breaks rock
21
Q
crystal growth (mineral hydration)
A
some minerals absorb water, mineral expands and exerts mechanical stress which forces rock grains apart
causes pressure in rock which breaks it apart
22
Q
salt wedging
A
occurs in arid climates
dissolved salt in ground water crystallizes/grows in open pore spaces in rocks and pushes apart rock grains
23
Q
thermal expansion
A
rock is heated and cooled through day/night
different minerals expand/contract at different rates causing rock stress
24
Q
thermal shock and examples
A
caused by extreme changes in temperature
rain on hot desert rocks
forest fire followed by rain
25
5 types of openings into surface bedrock
microscopic spaces
joints
faults
lava vesicles
solution cavities
26
2 types of joints
small and large
27
chemical weathering
decomposition of rock by alteration of its minerals
28
3 reacting agents for chemical weathering
oxygen
water
CO2
29
3 significant chemical processes in chemical weathering
oxidation
hydrolysis
carbonation/solution
30
oxidation and example
water combines with iron, aluminum etc
forms larger, softer and erodible compounds
rusting
31
hydrolysis and example
water combines with minerals
forms new, larger, softer and weaker compounds
water changes feldspar to form kaolin (play) and ions (dissolved materials)
32
carbonation/solution
CO2 and water make carbonic acid
carbonic acid and calcium carbonate create calcium bicarbonate
33
6 parts of the hydrological cycle
precipitation
evaporation/sublimation
transpiration
advection
runoff
infiltration
34
stream
body of running water confined in channel and moves downhill under influence of gravity
35
headwaters
upper part of stream in mountains
36
mouth
stream enters sea, lake or larger stream
37
flood plain
flat land adjacent to a stream
38
what do streams start from?
sheetwash and rills (tiny streams)
39
stream channels
long, narrow depression eroded by stream into rock/sediment
40
where does water spill onto after a flood?
flood plain
41
drainage basin
total area drained by a stream and its tributaries
42
tributary
small stream flowing into a larger one
43
divide
ridge/strip of high ground separating adjacent drainage basins
44
continental divide
divide separating streams flowing into different ocean/sea
45
drainage pattern
arrangement of a river and its tributaries
46
what 3 things influence drainage patterns?
rock type
jointing patterns
topography
47
dendritic
resembles tree branches
48
rectangular drainage pattern and where they are formed
tributaries that have 90 degree bends and join other streams at right angles
regularly fractured rock
49
trellis drainage pattern
parallel main streams with short tributaries that meet at right angles
50
radial drainage patterns and where they are formed
streams flow outward like spokes on a wheel
form on high conical mountains like composite volcanoes/domes
51
discharge formula
width x depth x velocity
52
discharge
volume of water that flows past given point in a unit of time
53
discharge in humid and dry climates
humid - discharge increases downstream
dry - discharge decreases downstream
54
stream erosion and deposition is controlled by what aspect of a stream?
velocity
55
stream velocity
distance water travels in a stream per unit time
56
stream velocity is controlled by what 3 things?
stream gradient
channel shape
channel roughness
57
stream gradient
downhill slope of a bed usually decrease downstream
58
3 types of channel shapes/roughness
semi-circular channel, flow rapidly
wide and shallow, flow slow due to friction
rough channel, slows streams
59
a stream with a narrow channel and hard rock will be fast or slow?
fast
60
a stream with a wide channel and soft rock will be fast or slow?
slow
61
what increases the velocity of a stream?
landslides/other obstructions
62
sediment is eroded by what 3 things?
hydraulic action
solution
abrasion
63
hydraulic action
ability of flowing water to pick up and move rock sediment
64
solution
rocks dissolved by water
65
abrasion
grinding away of a stream channel by friction and impact of the sediment load
66
bed load
particles are transported on or directly above stream bed
67
traction
rolling, sliding, dragging
68
saltation
bouncing/short leaps
69
suspended load
articles light enough to remain lifted above bottom by water turbulence
70
dissolved load
ions from chemical weathering
71
bars
ridge sediment usually sand/gravel deposited in the middle or along the banks
72
braided streams
stream that flows in a network of interconnected channels around numerous mid-channel bars
73
when do braided streams occur?
when stream has more sediment than it can carry
74
where do braided streams occur
arctic/mountainous regions
75
meandering streams (5 points)
streams tend to meander through sinuous curves of stream channels
low gradient
carry suspended load
common in lower reaches
76
what is created on the inside and outside curves of meandering streams?
inside - point bars
outside - cut bank
77
oxbow lakes
the cutoff meander
78
natural levees
low ridge of flood-deposited sediment on either side of stream channels
79
delta
body of sediment deposits at mouth of a river
80
when do deltas form?
when streams flow into body of standing water (lake or ocean)
81
3 kinds of deltas
wave dominated
tide dominated
river dominated
82
bottom sheet beds
fine silt and clay from suspended sediment
83
forest beds
large sandy sediment deposited at angle when bed load rolls over edge
84
topset beds
horizontal beds deposited
85
alluvial fans and where are they common?
large fan/cone shaped pile of sediment formed where a stream slows down rapidly from canyon to flat plain
arid and semi-arid mountainous regions
86
what happens to a streams discharge velocity and erosion during a flood?
increase
87
bypasses
built to divert water into designated flood plains
88
what are artificial levees built for?
built to protect cities
89
urban flooding
paved areas increase surface runoff
90
flood frequency curve
R = (n + 1)/m
R = recurrence time
n = number of years of record
m = magnitude rank
91
downcutting
process of deepening a valley by erosion of stream bed
92
base level
limit of downcutting
93
ultimate base level
sea level
94
lateral erosion
widening of valley; valley walls retreat by stream undercutting and mass wasting
95
headward erosion
stream lengthen its valley by uphill valley growth
96
stream terraces
step-like landform above a stream and its floodplain
97
incised meanders
sinuous pattern retained as streams downcutting
98
what are colluvial landforms/processes driven by?
acceleration due to gravity (mass movement)
99
colluvium
heterogenous mixture of materials that as result of gravitational action has moved down slope and settled at its base
100
colluvial processes are affected by what 7 things?
slope angle
weight from above
climate
slope material (grain size)
water (reduces frictional resistance)
time
The unexpected (earthquakes)
101
geomorphic threshold
angle before stuff starts to slide
102
stable slope
strength of slope exceeds denudation processes
103
unstable slope
slope materials weaker then denudation processes
104
what 4 things are used to classify mass movement?
slow
fast
wet
dry
105
flow vs slide
flow - moves as viscous liquid
slide - mass remain intact
106
soil creep
upper slope of soil creeps downhill
107
how does soil creep work?
freeze thaw process on slope causes ice expansion and that force is perpendicular with slope
in the spring the slope thaws/falls with gravity straight down slope
108
translational slide
blocks remain intact except they are stepped
109
height of waves are controlled by what 3 things?
wind speed
length of wind blowing time
distance of wind blowing over water
110
wavelength
horizontal distance between 2 crests
111
wave height
vertical distance between wave crest and wave trough
112
how do waves move?
particle of water moves in an orbit as wave passes
113
what is the diameter of wave orbits equal to?
wave height
114
orbits decrease in size with what?
depth
115
when does motion of an orbit die out?
depth equal to half of wavelength
116
surf
breakers in waves
117
wave refraction
bending of waves
118
tides
force generated by gravitational attraction of the moon and sun
119
what time of year is the height of tides enhanced?
spring
120
beach
strip of sediment that extends from low-water line to a cliff of a zone or permanent vegetation
121
beach face
steepest part exposed to wave action
122
berm
upper part wave deposited sediment platform
123
marine terrace
broad gently sloping platform
wave cut platform or wave built terrace
124
summer-winter cycle of beaches
winter - strong winds, high energy waves, berm erosion and sandbar formed
summer - calmer weather, low energy waves, sandbar pushed back
125
sea-ice rampart
ridge of sand and gravel pushed up by winter pack ice
126
longshore drift
movement of sediment parallel to shore when waves strike the shore at an angle
127
swash
wave run-up
128
backwash
wave return
129
spit
finger-like ridge of sediment that cuts a bay off from open ocean/lake
130
underwater canyons
considerable amount of drifting sand ended in the canyons and deep water
131
tombolo
bar of sediment connecting a former island to the mainland
132
barrier island
ridges of sand that parallel the shoreline and extend above sea level
133
lagoon
body of shallow sea water separated from sea by some form of barrier
134
jetties
rock walls to protect harbour entrance
135
groins
short walls perpendicular to the shore
136
breakwaters
offshore structures parallel to shore
137
3 sources of sand on beaches
erosion of local rocks
bioclasts from marine organisms
river sediments
138
what is the main source for sand on beaches?
river sediments
139
coastal straightening
process of wave erosion of headlands and wave deposition in bays
140
headland
point of land that extends out into body of water
141
sea cliff
significant vertical/near vertical rock exposure
142
sea cave
cavity eroded by wave action of cliff/rocks
143
sea stack
erosional remnant of headlands
144
sea arch
bridge of rock left above openings eroded in headlands
145
wave-cut platform
horizontal bench of rock formed beneath surf zone
146
estuary
drowned river valleys
147
fjord
drowned glaciated valleys
148
6 types of erosional landforms
headland
sea cliff
sea cave
sea stack
sea arch
wave-cut platform
149
reefs
formed by coral/other marine organisms important in forming limestone
found in tropical environments
150
fringing reef
attached to land, lack a lagoon
151
barrier reef
separated from land by lagoon
152
atoll
circular reefs that rime(?) lagoons formed from sinking of volcanic island
153
active continental margin and example
mainly found around pacific rim and are associated with earthquakes and volcanoes
pacific coast
154
passive continental margin and example
not technically active, lies at margin of an extending ocean
atlantic coast
155
continental shelf
shallow marine platform at the edge of a continent
156
how is sediment deposited on the continental shelf?
transported by rivers then moved by waves/tides
sand deposited near shore in shallow water
mus deposited at outer parts in deep water
relict coarse-grained sediments on outer continental shelves from the ice age
157
continental slope
relatively steep slope that extends from depth of 100-200m to depths of up to 5km
158
where does the continental slope extend deeper?
at active margin oceanic trench
159
submarine canyons
v-shaped valleys that run across continental shelves and down continental slopes
160
submarine fans
fan-shaped sediments deposited
161
turbidity currents
great masses of sediment-laden water that are pulled downhill by gravity
162
what are turbidity currents generated by?
earthquakes
landslides
strong storms
river floods
163
continental rise
a wedge of sediment that extends to deep ocean floor (abyssal plain) at base of continental slope of passive margin
164
abyssal plains
flat regions usually found at base of continental rise (mostly 5 km deep)
165
how are abyssal plains created?
enough sediments by turbidity currents to bury rugged relief and volcanic seamounts
166
terrigenous sediment
land derived from turbidity currents and distributed by contour currents
167
