Exam 1 Flashcards
(191 cards)
1
Q
What formed our moon?
A
Created from a collision with earth
2
Q
What is the theory of moon formation called?
A
Giant impact hypothesis
3
Q
What were the consequences of the impact?
A
Stabilized earth’s rotation, created varying seasons
4
Q
What is our current axial tilt?
A
23 degrees
5
Q
What most likely sourced our planetary water?
A
First theory: solar nebula contained ice that continues to be recycled through the earth’s mantle.
Second: ice rich asteroids (carbonaceous chondrites) brought water after the collision
6
Q
What is carbonaceous chondrite?
A
ice rich asteroids, some of the most primitive known meteorites, brought water post-collision
7
Q
Where did life likely originate on our planet?
A
Hydrothermal vents
8
Q
What is chemosynthesis?
A
Likely the origin of life on earth
9
Q
Compare chemosynthesis to photosynthesis?
A
Chemosynthesis: the use of energy released by chemical reactions (instead of the sun’s energy) to produce food
10
Q
What are extremophiles?
A
Prokaryotic bacteria
11
Q
What organic compound did the Rosetta mission find on the comet?
A
Phosphorous and Glycine
12
Q
Did the Rosetta mission prove that comets sourced our planetary water? Why or why not?
A
No, the water on comets had different isotopic properties than water on earth
13
Q
Describe how our early oxygens became oxygenated
A
Cyanobacteria absorbed sunlight and released oxygen in the process
14
Q
What are cyanobacteria?
A
Prokaryotic microorganisms capable of photosynthesis, earliest form of life
15
Q
What is a stromatolite?
A
A mound built up of layers of cyanobacteria, earliest fossil evidence of life on earth
16
Q
Prior to photosynthesis, how did life collect energy?
A
Getting energy from sulfate
17
Q
What is the leading theory for the cause of the Permian-Triassic extinction event?
A
Flood volcanism
18
Q
When did the PT extinction happen?
A
250 million years ago
19
Q
What percentages of terrestrial vertebrates (70%) and marine species (95%) perished?
A
95%
20
Q
What were some navigational techniques that the Polynesian Seafarers used?
A
Guiding by the stars/astronomy, stick charts, bird flight patterns, and ocean swells (observed waves and currents)
21
Q
What were some of the Polynesian Seafareres contributions to Oceanography?
A
oceanographic maps called stick charts, bird flight patterns, stars, ocean swell
22
Q
What contributions did Admiral Zhen He’s fleet make to oceanograph?
A
(advanced navigation maps, large sailing ships, compasses)? oceangoing vessels with compasses.
23
Q
How long was the HMS Challenger mission?
A
(4 years – 1872-1876)
24
Q
What were some of the contributions (first broad outline of oceans, ocean current plots, sea surface temperatures, 50 volumes of research, seafloor sediments)?
A
Described organism physiology in deep and shallow water via 50 volumes of research, discovered undersea mountains along the mid-Atlantic ridge, samples of seafloor sediment
25
What was the goal of the Jeanette Expedition?
to prove the open polar sea theory
26
How did the Jeannette Expedition fail?
the boat got stuck in ice
27
Where did the wreckage of the Jeannette Expedition finally settle?
Julianehab - near the southwestern corner of Greenland
28
What inspired Fridtjof Nansen to undertake the Fram Expedition?
Failure of the Jeannette expedition
29
What is the Transpolar Drift?
Major ocean current of the Arctic Ocean, transports sea ice around the Arctic ocean
30
What was Nansen able to prove?
The north pole was not located on land nor on a permanent ice sheet but that it is a shifting, unpredictable pack of ice
31
Describe Charles Darwin's theory on atoll formation?
Caused by sinking islands and upward developing coral reef in layers
32
What is the difference between a fringing reef and a barrier reef?
```
Fringing = coal grows
Barrier = a lagoon opens between the island and the reef
```
33
Why do Oceanic volcanic islands sink?
Plate tectonics (even though it wasn't accepted at the time) weight of coral also causes islands to sink
34
Where and when were deep ocean chemosynthetic ecosystems discovered?
Galapagos Rift 1977 - deep sea vents
35
What provides the foundation of these vent communities?
Chemolithoautotrophic bacteria use energy from vents
36
How big are giant tube worms?
8 feet
37
How do giant tube worms survive?
Chemosynthesis (found near hydrothermal vents)
38
In what direction do hurricanes rotate in the northern hemisphere?
Counterclockwise
39
What happens to cold water beneath a hurricane travelining across the ocean?
Surface diverge forms as hurricane sends heat/air up, surface diverge fills with cold deep water, nutrient-rich, upwelling occurs
40
What is the tallest "mountain" on earth with respect to the ocean's floor
Muana Kea, Hawai'i
41
How tall is Muana Kea (the tallest mountain on earth with respect to the ocean floor)
32,000 feet
42
What is the earth's longest mountain range?
Mid-Atlantic ridge
43
What is the depth in feet of the deepest ocean trench?
Mariana Trench 36,070 feet
44
How old are the oldest fossils on this planet?
3.7 billion years old
45
What are the oldest fossils on this planet?
Bacteria-like organism that photosynthesized and released oxygen into the atmosphere?
46
Where are the oldest fossils on this planet found?
northwestern Australia
47
What is the lithosphere?
(rigid, less dense) crust and extreme upper mantle
48
What is the asthenosphere?
(deformable, more dense) most of the upper mantle
49
Which is more dense, the lithosphere or the asthenosphere?
Asthenosphere
50
What are the chemical components of the crust?
Basalt ocean, granite contents
51
What are the chemical components of the mantle?
O2, Fe, Mg, Si
52
What are the chemical components of the cores?
Fe and Ni
53
Which is more dense - oceanic or continental crust?
Oceanic
54
Significance of March 27, 1964?
Alaska’s Good Friday Earthquake, 9.2 magnitude, 2nd most powerful earthquake ever recorded.
55
What did the Alaskan earthquake reveal?
It provided the P and S wave source that confirmed the theories of the earth’s interior layering.
56
What does “Seismic “ mean?
Relating to earthquakes or vibrations of earths crust
57
What are the 3 types of seismic waves?
Primary body waves, secondary body waves, surface waves
58
Describe primary body waves
compression, slinky, fastest, penetrate sold and liquid
59
Describe secondary body waves
snake-like, slower than P, can penetrate solid but NOT liquid
60
Describe surface waves
Ripple along surface, cause the most damage, slowest
61
Which are considered body waves?
P and S waves
62
Which waves travel the fastest?
P waves
63
Which waves travel the slowest?
surface waves
64
Which waves cause the most damage?
surface waves
65
How do body waves travel?
through the earth's interior in all directions
66
What are body waves speed influenced by?
Density
67
Waves travel ____ through higher density
faster
68
Waves refract ____ from higher density
away
69
Which of the body waves can travel through solids and liquids?
P waves
70
Our planet has a ____ inner core and a ____ outer core
solid inner core, liquid outer core
71
Our earth is ____ stratified
Density
72
What evidence did Alfred Wegener provide for his continental drift theory?
Similar animals and plant fossil found in different areas of the globe, coastlines align
73
Between the period of 1920-1960, what 5 additional scientific observations were made that supported Wegener’s theory? CMMSS
1. Clear patterns of earthquakes
2. Max age of seafloor is 2 million years old
3. Mid-ocean ridges conform to coastlines
4. Seafloor sediments thickest at ocean edges, sediments thinnest at mid-ocean ridges
5. Seismic waves slow down in the upper mantle
74
What ocean geological features are associated with the deepest earthquakes?
Trenches at subduction zones (convergent boundaries)
75
What is the half-life (in Billions of years) for Uranium 238? What is its decay product?
Half-life is 4.5 billion years, decay product is Lead 206
76
What do mid-ocean ridges conform to?
coastlines
77
Where are the thickest sediments found in the ocean?
At the edges of the ocean
78
Where are the thinnest sediments found in the ocean?
At the mid-ocean ridge
79
According to seafloor spreading theory, new seafloor develops at the ____ and spreads _____
ridge/rise
| out
80
Whats the source of power for sea floor spreading?
convection currents
81
What term refers to the destruction of crust?
subduction
82
When was sea floor spreading theory presented?
1962 by Hess & Deitz
83
What 3 theories most contibuted to the theory of plate tectonics?
Wegener - continental drift
Hess & Deitz - seafloor spreading
Vine & Matthews - paleomagnetisim/magnetic striping
84
How many lithospheric plates were originally thought to exist?
about a dozen
85
Who is credited with the plate tectonics theory?
Wegener (continental drift)
| Hess & Dietz (seafloor spreading)
86
What were Marie Tharp's contributions to oceanography?
Mapped mid-ocean ridges
| confirmed seafloor spreading theory
87
What is the periodicity of earth magnetic field polarity shifts?
Stripes of reversing polarity; one polarity will last between 0.1 and 1 million years; reversals take between 1,000 and 10,000 years
88
What is the age of the oldest oceanic crust?
200 million years old
89
Where is the oldest oceanic crust found?
Mediterranean
90
What are the 3 types of seismic waves?
Surface waves, P waves, S waves
91
How do surface waves propagate?
ripple along the surface
92
How do P waves propagate?
slinky - penetrate solid and liquid
93
How do S waves propagate?
snakey - penetrade solid but not liquid
94
Convergence and Divergence
Convergence- two plates coming together, destroying crust
| Divergent- mid ocean ridge, creating new crust
95
Spreading and Subduction
Spreading- mid ocean ridge, divergent boundary
| Subduction- convergent boundary, destroying crust
96
Creating and Destroying Crust
Creating- divergence, mid-ocean ridge
| Destroying- convergent, subduction zones
97
Passive and Active (Seismic Activity)
Passive- continental shelf, no seismic activity, East Coast
| Active- subduction zone, volcanic/EQ activity, West Coast
98
How do magnetic “stripes” on the ocean floor prove that oceanic crust is being created at a ridge?
Paleomagnetism: alternating “stripes” of polarity on seafloor. New seafloor develops at mid-atlantic ridge, spreads outward, alternating in polarity
99
When does oceanic crust conform to the earth’s polarity?
Oceanic crust created during normal event, when north pole aligned with geographic north, would have polarity aligned with the earth’s current magnetic field
100
Which is spreading faster – The Mid Atlantic Ridge or the East Pacific Rise?
Mid Atlantic ridge
101
How do we know the mid-Atlantic ridge is spreading faster?
age of seafloor near continents is younger on the west side of south america than on the east side
102
Which magnificent 7 is the Peru Chile trench?
o/c/c
| Oh its the peru Chile trenCh
103
What are the Andes mountains?
mountain arc
104
How are the Andes mountains aligned to the trench?
Parallel to trench
105
Howa re the Andes mountains aligned to plate motion?
Perpendicular to plate motion
106
Which magnificent 7 is the Juan/De Fuca ridge?
o/c/c
| Juan was on the OC
107
How were the Cascade mountains formed?
subduction of Juan de Fuca plate under the North American plate
108
Which magnificent 7 is the Aleutian trench?
o/o/c
109
What are the Aleutian islands?
island arc
110
How are the Aleutian islands aligned to the trench?
parallel to trench
111
How are the Aleutian islands aligned to plate motion?
perpendicular to plate motion
112
What formed the Hawaiian islands?
hot spots
113
Are the Hawaiian islands an island arc or island chain?
island chain
114
How are the Hawaiian islands aligned with respect to plate motion?
parallel
115
Which magnificent 7 is the east pacific rise?
o/o/d
116
Which magnificent 7 is the Marianas trench?
o/o/c
117
Which magnificent 7 is the Himalayan mountains?
c/c/c
118
Which magnificent 7 is the Sumatra trench?
o/c/c
119
What formed the Emperor seamounts?
Volcanism from pacific plate passing over a hotspot?
120
Are the Emperor seamounts a submerged island arc or island chain?
island chain
121
How are the Emperor seamounts aligned with respect to plate motion?
parallel to plate motion
122
Which magnificent 7 is the red sea/gulf of aden, east africian rift zone
c/c/d
123
Which has rifted the most: Red Sea, Gulf of Aden, East Africian rift zone?
Red sea
124
What type of plate boundary is associated with the San Andreas fault?
continent/continent transform
125
How old are the rockies?
300 million years old
| modern is 70-55
126
How were the rockies formed?
Shallow angle subduction of Farallon Plate. (Another answer:) a shallow subduction because it is warmer, young. Ridge producing ocean crust, subducting/less dense and less steep causes a compression that elevated the Rockies
127
How old are the rocks that make up the flatirons?
280 million
128
When were the flatirons uplifted?
65 million
129
how old are the rocks that make up flagstaff peak in boulder?
1.7 billion
130
What is convergence?
2 plates coming together, destroying crust
131
What is divergence?
mid-ocean ridge, creating new crust
132
What is spreading?
mid-ocean ridge, divergent boundary
133
What is subduction?
convergent boundary, destroying crust
134
What is creating crust?
divergence, mid-ocean ridge
135
What is destroying crust?
convergent, subduction zones
136
What is passive seismic activity?
continental shelf, no seismic activity, east coast
137
What is active seismic activity?
subduction zone, volcanic/earthquake activity, west coast
138
What are the 3 primary categories of plate boundaries?
convergent, divergent, transform fault
139
What are the magnificent 7?
ocean/ocean convergent
ocean/ocean divergent
ocean/continent convergent
continent/continent convergent
continent/continent divergent
transform fault
140
Mag 7: what is the Marianas trench?
ocean/ocean convergent
141
Mag 7: what is the Aleutian trench?
ocean/ocean convergent
142
Mag 7: what is the mid-atlantic ridge?
ocean/ocean divergent
143
Mag 7: what is the east pacific ridge?
ocean/ocean divergent
144
Mag 7: what is the peru chile trench?
ocean/continent convergent
145
Mag 7: what are the Himalayan mountains?
continent/continent convergent
146
Mag 7: What is the red sea?
contient/continent divergent
147
Mag 7: what is the San Andreas fault?
transform fault
148
What will we find at an ocean/ocean convergent boundary?
trench
149
What forms on the backside of that feature?
island arcs
150
What will we find at an ocean / continent convergent boundary?
trench
151
What forms on the backside of an ocean / continent convergent boundary?
mountain arc
152
Ocean ridges/rises are associated with ___ plate motion and ___ oceanic crust
Ocean Ridges and Rises are associated with divergent, passive plate motion and the creation of oceanic crust.
153
Trenches are associated with ____ plate motion and _____ oceanic crust.
Trenches are associated with convergent, active plate motion and the destruction of oceanic crust.
154
Ridges / Rises create __
new oceanic crust
155
Provide an example of an Ocean / Ocean Convergent Boundary
Aleutian islands
156
Provide an Example of an Ocean / Continent Convergent boundary
Andes mountains
157
What is the subduction angle difference between the plate that produced the Rockies and the Andes Mountains in South America?
The Rockies formed from the subduction of younger and hotter oceanic crust thus resulting in a shallower angle. The Andes formed from older and cooler oceanic crust subduction, resulting in a steeper angle.
158
What is the age of the oldest ocean crust on the planet?
200 million years
159
Which is spreading faster, the Mid Atlantic Ridge or the East Pacific Rise?
east pacific rise
160
Which type of plate boundary constructed the Himalayan mountains?
continent/continent convergence
161
What is the utility of satellite radar altimetry?
satellites measure gravity by microwaves
162
The basic premise for satellite altimetry is that gravity causes the sea surface to ___ over sea mounts and ___ over trenches
The basic premise for satellite altimetry is that gravity causes the sea surface to elevate/rose over sea mounts and sink/depress over trenches
163
What forms on the “back side” of an Ocean / Ocean Convergent plate boundary?
island arc
164
What forms on the “back side” of an Ocean / Continent Convergent plate boundary?
mountain arc
165
What formed the Hawaiian Islands?
pacific plate moving over hotspot
166
how are islands aligned in relationship to plate motion?
parallel to plate motion
167
hat are the three features associated with a Transform (fault)?
fracture zone, transform fault, ridge
168
which of the three features are seismically active?
transform fault
169
What feature differentiates the difference between an Active and Passive Margin?
Active- EQs, volcanism, trench, subduction, convergent boundary
Passive- continental shelf, no EQs/volcanism
170
Identify whether Continental Margins are: passive or active
active if it has a trench, passive if it doesn't have a trench
171
Identify whether Continental Margins are: seismic or not
seismic if it has a trench
172
Identify whether Continental Margins are: pacific or atlantic type
```
pacific = no trench
passive = atlantic
```
173
Hurricanes rotate clockwise in the
southern hemisphere
174
he oldest ocean's crust age is approximately
200 million years old
175
Seismic body waves travel ___ through a higher density medium
faster
176
Seismic body waves ___ from higher density layers of our inner earth structure
refract away
177
Seismic body waves refract away from ___ density layers of our inner earth structure
higher
178
Additional evidence for Alfred Wegener's continental drift hypothesis:
clear patterns of earthquakes and volcanoes associated with ridges, trenches, and faults, radiometric dating, mid-ocean ridges conforming to coastlines, varying sedimentology- older oceanic crust (farthest from ridge) had thicker sediment
179
Magnetic striping theory:
symmetrical patterns of alternating earth polarity on each side of a spreading center (ridge)
180
New oceanic crust is created at
ridges
181
New oceanic crust is destroyed at
trenches
182
Twin convective cells in the upper mantle provide a ___ stress to lithospheric plates underneath ___
divergent
| ridges
183
he Aleutian trench is a ___ plate boundary
convergent
184
What convergent boundaries produce island arcs?
ocean to ocean plate convergent boundaries produce island arcs
185
Volcanic island arcs are aligned ____ to plate motion
perpendicular
186
Island chains are produced by ___and are aligned ___ to plate motion
hot spots
parallel
187
The basic premise for satellite altimetry is that
The basic premise for satellite altimetry is that gravity causes the sea surface to elevate/rise over sea mounts and depress/dip over trenches
188
The Himalayan mountains were formed by ____ plate activity
The Himalayan mountains were formed by continent/continent convergent plate activity
189
What forms on the backside of of an ocean/ocean convergent plate boundary (trench)?
island arc
190
How is a mountain arc alignment related to plate directional motion?
perpendicular
191
Transform faults are seismically ___
active
