MIDTERM 1 Flashcards
(170 cards)
1
Q
Geodesy
A
science of measurement of earth through surveys and mathematical calculations
2
Q
Eratosthenes
A
calculated circumference of the earth
3
Q
Biruni
A
calculated circumference of the earth
4
Q
Datum
A
known/constant surface used to describe location of unknown points
5
Q
reference ellipsoid
A
a math model
6
Q
Geoid
A
3D shape of earth considered as mean sea level extended continuously through continents
7
Q
flattening
A
correction/description between major/minor axis for odd shape of earth
8
Q
5 themes of geography
A
Location
Region
Human-earth relationships
Place
Movement
9
Q
longitude
A
Great Circle: intersection of a sphere and plane which passes through the center point of the sphere
360
180 E and W
10
Q
what number value is the prime meridian?
A
0
11
Q
Graticule
A
establish grid of intersecting lines (coord system) to find locations
12
Q
what are graticules written as?
A
degrees, minutes (‘) and seconds (“) for NS and EW
13
Q
how is longitude determined?
A
cartographer determines solar noon
when sun is at zenith, it is 12 noon locally
compare this time to Greenwich
difference in time of local time - Greenwich is converted to longitude and degrees
14
Q
what 3 shapes are maps projected off?
A
plate, cone or cylinder
15
Q
cylindrical projections
A
use for the entire world
parallels and meridians are straight lines
16
Q
standard line
A
imaginary point of contact
17
Q
tangency
A
only one point touches surface
18
Q
secancy and what does it do?
A
projection surface cuts through globe
reduces distortion of larger land areas
19
Q
conical projection
A
can only represent one hemisphere
used to represent areas with E-W extent (ex. Canada)
area remains true
20
Q
Planar projection (azimuthal)
A
used to show route distances
distances measured from centre are true
distortion of other properties increase away from centre point
21
Q
Gnomonic
A
scale increases rapidly from centre so equator cant be shown
22
Q
stereographic
A
shows one hemisphere but with increasing distortion
conformal projections
23
Q
orthographic
A
can show 1 hemisphere as seen from space
24
Q
projections are linked with what? How?
A
Datums
Maps in same projection different datums do not overlay correctly, maps in same datum different projections do not overlay correctly
25
what 3 things do all maps have?
scale, compass rose, legend
26
what 4 things do most maps have?
title, projection, cartographer, date
27
What 3 things do some maps have?
grid system, inset maps and locator maps
28
scale
ratio between map distances and earth distances
29
Large, intermediate and small scale maps
Large - 1: 50,000 or smaller
Intermediate - 1: 50,000-250,000
Small - 1: 250,000- ?
30
Spot elevations
heights between contour lines
31
Endogenic processes
processes that build landscapes
32
Exogenic processes
?
33
uniformitarianism
process occurring today are same ones that occurred in the past
34
catastrophism
nothing we see today is result of short term processes
geological features formed by catastrophic events over short periods of time
35
Time (sediment and superposition)
Youngest beds of rock are near surface of rock formation
oldest are at base if no disturbance
36
How does the earth form landscapes?
combination of time, uniformitarianism and catastrophism
37
2 geological time scales
Absolute time
Relative time
38
what is absolute time based on?
radiometric dating
39
what assigns time units to rocks?
Absolute time
40
Relative time
established relative time rock was formed
41
the 3 principles used to determine relative age
Original horizontality
Lateral continuity
Superposition
42
Original horizontality
beds of sediment deposited in water formed as horizontal/nearly horizontal layers
43
Lateral continuity
original sedimentary layer extends laterally until it tapers/thins at edges
44
Law of superposition
with sequence of undisturbed sedimentary/volcanic rocks layers get younger from bottom to top
45
2 principles used to determine relative time
cross-cutting relationships
Inclusion
46
Cross-cutting relationships
disrupted pattern is older than cause of disruption
47
inclusion
fragments included in host rock are older than host rock
48
isotope
varieties of an element with different number of neutrons
undergo radioactive decay
some are unstable
49
Half life
time it takes for isotope to be reduced by one half
50
how old is the earth?
4.5-4.6 billion years old
51
when was the precambrian?
544 million years ago
52
when was the permian-triassic?
251 million years ago
53
when was the Cretaceous-tertiary?
65 million years ago
dinosaur period
54
when was the tertiary-quarternary?
2 million years ago
55
what process formed the solar system/earth?
nebula hypothesis
56
the 4 layers of earth
crust
mantle (silicate)
outer core
inner core
57
continental crust (4 traits)
mostly granite
low density
made up of Si, Al, K, Ca and Na
ferrous and silicon
58
Oceanic crust
Mostly basalt (granular)
High density
Si, Mg and Fe
Magnesium and Ferrous (mafic)
59
Principle of buoyancy
object will float as long as it weighs less then weight of substance its in
60
Principle of isostasy
state of equilibrium in earths crust due to buoyancy
61
Minerals
elements combined
62
Minerals combine to form what?
Rocks
63
ingneous processes
igneous rocks solidify/crystallize from molten state
64
cooling history of an igneous rock determines what aspect of a rock?
rock texture
65
the 3 types of sedimentary processes
Clastic (cemented)
Chemical precipitated rocks
Chemical sedimentary rocks
66
Evaporites
formed by precipitation of minerals when water evaporates
67
Limestone and the 2 major types
composed of calcite, caCO3
Biochemical and Inorganic
68
3 kinds of biochemical limestone
Coquina: shell fragments
Chalk: planktonic organisms
Bioclastic: wave-broken fragments of algae, corals and shells
69
3 kinds of inorganic limestone
Oolitic: cementation of oolites
Travertine: raid precipitation of calcite
Tufa: precipitation from solution in water of continental spring, lake from groundwater
70
where is travertine found?
mouth of hot springs/limestone caves
71
example of an organic rock
coal
72
metamorphic processes
any igneous/sedimentary rock that transformed into metamorphic rock
harder rocks and more resistant to weathering/erosion
73
plate tectonics
theory that earths surface is divided into series of plates moving toward, away or past one another
74
continental drift
theory suggesting continents are floating around earths surface
75
who suggested in 1915 that continents used to be joined in one giant land mass and continents have drifted around?
Alfred Wegner
76
what evidence suggests for Pangea? (5)
jigsaw puzzle fit
permian rock strata in India, Australia, South America, South Africa (same plant species on differing continents)
permian fossils are similar in widely spread continents
permian glacial patterns
structural trends in mountain ranges line up
77
Paleomagnetism
study of magnetic field preserved in rocks from the past
78
paleomagnetism gives what 3 pieces of information?
direction to paleo-magnetic pole
polarity of magnetic field
magnetic inclination
79
magnetic inclination
angle from horizontal assumed by free bar magnet
80
rock with Fe-bearing minerals record what 3 things about the magnetic pole?
strength
position
polarity
81
polar wandering
wandering of magnetic poles over the planet in the past
82
who proposed the idea in 1962 that the seafloor spreads?
Harry Hess
83
polarity of the earth changes every how many years?
250,000 years
84
what term refers to past polarity changes over time?
magnetostratigraphy
85
magnetic epoch
long period of time which polarity is dominantly normal to reverse
86
magnetic event
magnetic reversal for short period of time
87
how many major plate types are there?
7
88
how far does the ocean floor spread/year?
1-20 cm/yr
89
what 3 things cause plate motion?
earths internal heat source of energy driving movement
convection in mantle
lithosphere has energy of motion (slides on top of asthenosphere)
90
what 3 mechanisms cause plate motion?
Ridge push
Slab pull
Trench suction
91
ridge push
spreading at ocean ridges pushes plates aside
92
slab pull
descending ocean lithosphere pulls rest of plate along with it
93
trench suction
at trenches, subjecting plates fall into asthenosphere at steeper angles
94
mantle plumes/hot spots
localized regions of heat flow in mantle
cause melting in overlying crust
remain fixed for 20-100 million years
95
what is constantly happening to the earths lithosphere?
being created (sea floor spreading) and destroyed (subduction)
96
subduction
cold ocean lithosphere descending into mantle
97
3 types of plate boundaries
divergent
convergent
transform
98
divergent plate boundaries
plates moving apart from each other
99
continents may rift to form what?
oceans
100
3 types of continental rifting
uplift
rifting
drift
101
convergent
2 tectonic plates that move towards each other and collide
102
what does the collision of convergent plate boundaries create?
earthquakes, volcanoes, mountain ranges
103
what 2 things can happen to converging plates?
Subduction
Collision
104
3 types of plate convergences
ocean-ocean convergence
ocean-continent convergence
continent-continent convergence
105
what 4 things are revealed with an ocean-ocean subduction?
Benioff zone
andesitic/basaltic island arcs
Forearc/backarc basin
accretionary wedge
106
Benioff zone
shallow to deep focus earthquakes
107
what 7 things are revealed with an ocean-continent subduction?
Benioff zone
Andesitic magmatic arc
Forearc basin
accretionary wedge
mountain belts
Backarc thrust belt
Foreland basin
108
what happens when 2 continents collide?
mountains form
shallow focus earthquakes
109
what marks the end of the Wilson cycle?
a continent-continent convergence
110
wilson cycle
plate tectonics cycle from continental rifting to continent-continent convergence
111
what does the complete closure of an ocean create?
supercontinent
112
transform plate boundaries
sliding past each other resulting in shearing
113
where do transform plate boundaries occur?
sections of ocean ridges where plates moving opposite directions meet
114
transform faults
displacement along fault end or transforms into another kind of displacement
115
surface relief and the 2 kinds
the depressions and elevations in surface of the earth
high and low
116
High and low surface relief examples
High: Columbia ice field, AB
Low: wheat fields, SA
117
the 3 orders of relief vertical elevation differences
First: continents/oceans
Second: mountain ranges, plains, lowlands
Third: individual mountains, cliffs, valleys, hills
118
topographic regions
large areas with consistent land surface character
119
4 kinds of continental crust formations
Cratons
Terranes
Diastrophism
Volcanism
120
Cratons
basement rock
continental nucleus
oldest rock; dates to pre cambrian
121
craton examples
Continental shield
Platform
122
Continental Shield
exposed basement rock surrounded by younger sedimentary rock
123
Platform
covered basement rock by younger sedimentary rock
124
what is basement rock made of?
granite, gneiss, schist, sedimentary rocks
125
example of a continental shield
Canadian Shield (central labrador)
126
terranes
material from asthenosphere that upwells along sea floor spreading centres
127
accreted terrane
fragments of crustal material formed on/broken off from one tectonic plate and sutured to crust lying on another plate
128
what forces can lead to crustal deformation?
tectonic forces, gravity, weight of overlying rocks
129
diastrophism
deformation of the earths crust
movement of solid crust material causing rock to be bent/broken as result of pressures from plate tectonics or rise of magma from below
130
3 kinds of rock stress
tension
compression
shear
131
strain and the 2 forms of it
how rocks respond to stress
faulting (breaking)
folding (bending)
132
where does rock folding occur?
convergent plate boundaries
133
5 types of rock folding
syncline (centre of rocks sink)
anticline (centre of rocks arch)
monocline (bend in parallel layers of rock)
overturned (superposition interrupted)
overthrust (fracture)
134
axis
line that runs along anticlinal ridge/synclinal bottom (strike)
135
Dip
angle of inclination of axis
136
plunge
depression of axis
137
5 kinds of rock faults
Normal
Reverse
Strike-slip
Overthrust
Horst and graben
138
Overthrust fault
compressional force pushes rock up and onto another land mass
139
Horst and Graben fault
middle block of land sandwiched between land masses sinks down/forms ditch between 2 land masses
140
orogenesis
process of creating mountains
141
3 types of orogenesis
oceanic-continental plate collision
oceanic-oceanic plate collision
continental-continental plate collision
142
what orogenic process created the Himalayan mountains?
continental-continental plate collision
143
what orogenic process created mountains along the pacific coasts of N and S America?
Oceanic-continental plate collision
144
what orogenic process created the mountains along western pacific rim?
oceanic-oceanic plate collision
145
volcano
hill/mountain contracted by extrusion of lava/rock fragments from vent
146
magma composition, temp and viscosity influences what 4 things?
explosiveness of eruption
types of material produced
volcanic hazards
volcano shape
147
what causes the explosion of an eruption?
magma gas and pyroclasts that are formed from excreting lava is trust into the air with a drop in pressure near the earths surface
148
what 2 things influence the intensity/explosiveness of an explosion?
amount of gas in magma/lava
the ease/difficulty with which gas can escape into atmosphere
149
what kind of rock has the lowest volcanic explosions?
basaltic
150
what kind of rock has the biggest volcanic explosions?
Rhyolitic
151
viscosity
resistance to flow
152
what 3 things is viscosity determined by?
silica (SiO2) content of magma
temp of lava relative to solidification
gas dissolved in magma
153
the 8 classifications of volcanic eruptions
hawaiian
Strombolian
subplinian
pinion
ultraplinian
vulcanian
surtseyan
Phreatoplinian
154
hawaiian eruptions
<2km
hawaiian islands have low viscosity basalts (low intensity eruptions)
lava fountains, lakes, rivers
155
Strombolian eruptions
<10km
named from Stromboli volcano in aeolian island
intermittent eruptions
med-low viscosity magma
ex. Mt. Etna
156
subplinian eruptions
<30km
named after Pliny the younger who witnessed/described eruption of Mt Vesuvius in 79 AD
157
Plinian eruptions
<55km
eruptions that make history
hot gas is shot into atmosphere creating convection
convection carries ash into stratosphere reducing solar radiation for months/years
ex. Mt. pinatubo
158
Vulcanian eruptions
explosion of magmatic gas associated with water
explosions of med-high energy
produce lava flows and pyroclasts
159
Pahoehoe
twisted, ropy or billowy surface
ex. rough, jugged rubbly surface
160
what materials are in pyroclasts?
ash/tephra
161
tufts/volcanic breccia
rocks formed from pyroclastic materials
tufts: ash and lapilli
volcanic breccia: bombs, blocks
162
pyroclastic fall
materials fall from air
163
tephra
unconsolidated blasted material
164
pyroclastic flow
clouds of pyroclasts too dense to rise in air and flows down volcano slope
165
example of a pyroclastic flow
Mt. pelee destruction of st Pierre (killed 14,000, only 4 lived)
166
lahar
mudflow caused by melting ice/snow on volcano
167
flood basalts
repeated eruption of fluid basaltic lava over large areas
168
fissure eruptions
erupt through a crack
169
example of fissure eruption
Columbia rive plateau
170
columnar jointing
parallel, vertical column, 6-sided joints formed by basalt contracting as it cools after solidifying
