MIDTERM 3 Flashcards
1
Q
pelagic sediment
A
slowly settled clays from wind/volcanic ash and skeletons of microorganisms
2
Q
how much of earths freshwater is in ice?
A
77%
3
Q
snowline
A
lowest line where winter persists all summer
4
Q
what is the snowline at the equator?
A
5000m
5
Q
what is the snowline at the alps?
A
2700m
6
Q
what is the snowline in western BC?
A
1500-2500m
7
Q
alpine glaciers
A
mountain (European alps and Rocky Mountains)
valley and cirque glaciers
8
Q
continental glaciers
A
large scale, continuous mass of ice (Greenland, Antarctica, smaller ice fields)
9
Q
3 glacial processes
A
formation of glacial ice
glacial mass balance
glacial movement
10
Q
glacial ice formation
A
snow accumulates in layers and creates snowfield
thickens and increases weight and pressure and crystallization begins
spring/summer snowmelt seeps into snowfields and refreezes
transitions into firn/nerve (compact granular structure)
dense glacial ice is formed over many years
11
Q
what type of rock are glaciers?
A
metamorphic
12
Q
shape of ice crystals change with what?
A
density
13
Q
ice regelation
A
rock picked up by glacial movement
14
Q
equilibrium line altitude
A
line between net accumulation of ice and loss through melt and sublimation (solid to liquid state)
15
Q
bergschrund
A
point of initiation of movement where a glacier is pulled away
16
Q
icefall crevasse seraces
A
ice found between 2 glacial crevasses
17
Q
cirque
A
horseshoe shape glaciated depression created when a glacier is pulled away from a mountain and pulls land with it
18
Q
tarn
A
glacial-formed lake inside a horseshoe shape cirque
19
Q
horn
A
cirques created on all sides of a mountain creating horn
20
Q
arete
A
ridge between 2 cirques
21
Q
col
A
low spots in arete ridge
22
Q
hanging valley
A
as glacier meets another glacier it hangs over another glacier
23
Q
striation
A
scrapings on a rock from a glacier scraping as it moves
24
Q
what do some striation scratches leave behind?
A
flutes
25
where does deposition occur during glacial movement?
end of the glaciers movement
26
terminal moraines and example
when glacier pushes land like a bulldozer and then when it melts it recedes and leaves pile of broken rock
athabasca glacier, alberta
27
lateral moraines
pile of broken rock on the side of glacier movement
28
till
unsorted, broken, angular material of all sizes jumbled together; no sorting
29
ground moraine
ground that has been flattened from moving glaciers
30
surface sources for water on glaciers
surface melt of snow/ice
rainfall runoff
lake discharge
31
basal/internal sources of water on glaciers
melt of basal ice by geothermal heat
frictional melt at glacier bed
32
drainage routes on glaciers
supra glacial streams
moulins and crevasses
marginal/submarginal channels
subglacial routeways (sheet flow, channels, braided streams etc.)
proglacial streams
33
moulin
glacial sinkhole
34
3 types of glacial channels
marginal
submarginal
subglacial
35
subglacial chutes
when melt water drops down a moulin then flows laterally across glacier bed
36
esker
stream bed of subglacial stream
old channel beds
37
kame
sands/gravels dumped from and end/supraglacial position
sediment deposit by ice contact water in crevasses
38
kame terrace
pile of material left exposed after ice has melted away
39
kettles
enclosed depressions formed by burial of blocks of stagnant glacier ice under sediments/till
melts slowly forming hollow
40
outwash plain
unconstrained large, flat, similar to ground moraine but sorted sediment
41
what's are landforms.deposits associated with ice-dammed lakes?
shorelines, deltas, rhythmites and dropstones
42
difference between an outwash plain and till
outwash plain (stratified)
till plain (unstratified)
43
drumlins
blunt end upstream, taper downstream, in groups and parallel
44
jokulhaup
glacier outburst flood, caused by breaching of ice/moraine dam
45
what was the last glaciation
wisconsinan
46
what's parts of BC used to never be covered in glacier ice from the wisconsinan?
nunataks (high peaks above glaciers)
refugia
brooks peninsula Van island
47
where did the glaciers melt from
top down from ELA
high elevations melted before low elevations
48
what % of earth surface is permafrost, frost action and ground ice?
20
49
periglacial landscapes
cols-climate processes, landforms, and topographic features at margins of glaciers
50
in areas of permafrost, frozen subsurface water is called what?
ground ice
51
what3. things does frost action do?
shatters, heaves (vertical) and thrusts (horizontal)
52
pingo
heaved-up ice cored mound sometimes by artesian water injected into permafrost
53
palsa
mound but have growth on top of permafrost; permanently frozen peat
54
patterned ground
frost action where coarser particles move towards surface in polygon/netted shapes
55
wind produced landforms through what 3 processes
eroding
transporting
depositing
56
2 types of erosion
deflation
abrasion
57
deflation
loose particles carried away with wind or driven deeper with water
58
blowout depression
low places on the landscape
59
desert pavement
wind moves everything away except large bits
60
abrasion (sandblasting)
produces pitted, grooved and/or polished surfaces
also produce ventifacts
61
yardangs
elongated shapes parallel to wind erosion
62
toad-stools
undercut, mushroom shaped pedestal rocks in desert areas attributed to wind erosion
63
ventifacts
wind-eroded rocks
64
2 types of ventifacts
yardangs
toad-stools
65
dust storms
fine. silt size particles carried into troposphere-tropopause
up to 10,000m
66
sandstorms
sand sized particles carried only 2m above ground
movement is by saltation
67
ripples
smallest feature deposited by wind
formed at right angles to wind direction
68
dunes
accumulation of sand shaped by wind capable of movement
69
where do dunes form?
lees
70
size, shape and orientation of dunes are determined by what 3 things?
sand
vegetation
wind
71
barchan
crescent shape, horns point downward
limited sand availability
72
transverse (c)
more abundant sand availability than barchans
73
parabolic
anchored by vegetation
look like barchans except horns anchored by vegetation
74
3 crescentic class dunes
barchan
transverse (c)
parabolic
75
3 linear class dunes
longitudinal
transverse (L)
star
76
longitudinal dunes
results from strong, one directional winds
77
transverse (L) dunes
massive volumes of sand, low speed consistent wind
78
star dunes
inconsistent wind direction
79
loess
wind blown materials that self bind through arranging and cover a landscape
80
when do loess occur?
when there is not sand
81
desert varnish
rapid evaporation after precipitation causes precipitation of solid manganese oxide on rock surfaces
82
the 3 causes of distribution of deserts
sub-tropical high pressure zone between 15-35 degrees N and S latitude
rain shadow of lee side of mountain ranges
areas great distance from moisture
83
soil components
minerals (40-50%)
air and water (40-50%)
organic matter (1-10%)
84
3 soil properties
chemical (oxidation, reduction)
physical (texture, density)
biological (insects, droppings, fungi, worms, plants/roots, bacteria)
85
pedon
unit of soil 1m squared with all horizons
86
solum
layers of soil affected by climate and vegetation
usually 5 layers deep
87
4 types of mineral horizons
O (organic)
A (zone of leaching)
B (zone of enrichment)
C (little soil development)
88
10 common soils in BC
Luvisols
Brunisols
Gleysols
Regosols
Organic soils
podzols
Chernozem
cryosols
solonetz
vertisol
89
luvisols
clay enrichment of B horizon
gray color and good plant growth
90
gleysols
water saturation produces reducing environment
poorly drained and anaerobic
91
regosols
from regolith; weakly developed soils
unstable environments
92
podzols
coastal high elevations where high precipitation occurs
excellent growing medium
well drained, coarse texture
93
chernozem
prairie soil
grassy areas
limited soil leaching die to low precipitation
94
cryosols
frozen, tundra like
permafrost
alpine areas
95
solonetz
salt deposited soils
grasslands with high evapotranspiration
deposition of salts near soil surface
dry regions
96
vertisol
dry, clay-bearing soils
97
earthquake
ground motion caused by release of energy stored in rocks
98
seismic waves
waves of energy produced by an earth quake
99
seismology
the study of earthquakes
100
where do deep earthquakes occur?
subduction zones (100-670 km)
101
focus (hypocenter)
exact spot in earth where earthquake originates
102
epicenter
point on surface of earth directly above earthquake focus
103
body waves
travel through earths interior spreading outward from the focus in all directions
104
p waves
push-pull or compression/primary waves
compressional wave, rock vibrates parallel to wave travel
cause volume changes
can pass through solids, liquids and gases
105
s waves
shear waves/secondary waves
rock vibrates perpendicular to wave direction
only pass through solids
106
4 types of seismic waves
body waves
surface waves
love waves (side to side)
Rayleigh wave (move up/down)
107
seismometer
measure seismic waves
108
seismograph
recording device on rotating paper
109
seismogram
paper record of earths vibration
110
what order do waves arrive in?
P waves
S waves
surface waves
111
2 ways to measure earthquake sizes
intensity
magnitude
112
different between intensity and magnitude
intensity = damage
magnitude = energy released
113
logarithmic scale
every 1pt increase = 10x increase in wave amplitude
every 1pt increase = 32x increase in energy released by earthquake
114
ground motion
from seismic waves (surface waves) causes building destruction
115
liquefaction
water saturated soil/sediments turn to liquified state from a solid state as result of earthquake shaking
116
8 types of earthquake damage
ground motion
fire
landslides
liquefaction
displacement of land surface
tsunami
aftershocks
foreshocks
117
where do earthquakes occur?
circum-pacific belt made of Benioff zones
mediterranean-himalayans belt
mid-oceanic ridges
118
what happens before a large earthquake?
cracks may open in the rock and there is a change in porosity
119
what are some signs of an earthquake occurring?
foreshocks
water level changes in wells
increase in radon emission from wells
changes in rocks magnetism
electrical resistivity and seismic velocity
surface of earth tilts and changes elevation
animal behavior
120
seismic gaps
short/inactive segments along some long active faults
121
WCDA have how many GPS tracking stations in BC and what do they do?
8
monitor crustal motions
provide info for modelling of plate interactions
help in estimation of current seismic hazard
122
when was the last mega thrust?
January 26th, 1700 @ 9 pm
123
how many mega thrust earthquakes have been identified in the last 6000 years?
13
124
natural wetlands
impoundments that have biological/ecological functions
125
benefits of natural wetlands
storage of water
transformation of nutrients
growth of living matter
diversity of wetland biota
126
bog
vegetation shows effects of high water table and slack nutrients; acidic water; flat topography; sphagnum hummocks
127
fen
high water table, drains low gradient, higher nutrients, grasses, shrubs small trees
128
peat forming wetland areas
bogs and fens
129
non peat forming wetland areas
swamps
marshes
shallow open water (ponds, slough)
130
swamps
standing/moving water occurs seasonally, soils continuously waterlogged, Ph neutral, rich in oxygen/nutrients, abundant trees
131
marshes
periodically inundated with water, nutrient rich, oxygenated, sedges rushes and reeds
132
ponds/slough
no emergent vegetation but can have floating/rooted aquatics
133
natural wetland classifications depend on what 6 things?
hydrology
climate
soil
landform
vegetation
fauna/permafrost
134
what % of BC is wetlands
0-5%
