Final Review Flashcards
Final Review (100 cards)
1
Q
What is the most useful in studying the earth’s inner core?
A
Meteorites
2
Q
Rocky mountains have a lower gravity value than expected due to:
A
-Mountain crust is made up of less dense material
-Thicker crust at the mountains due to “root” of crust extending into the mantle
3
Q
What is not a cause for plate motion?
A
Crustal uplift
4
Q
Which is not commonly used to determine direction of plate movement?
A
Island arcs
5
Q
The length of time for the Wilson cycle is?
A
500 Million Years
6
Q
The failed rift valley formed during initial rifting can help to explain:
A
Large rivers
7
Q
Which process does not help produce thicker deposits along passive margin shelves:
A
Island arcs trapping sediment
8
Q
Which is not evidence supporting that smaller individual magma chambers rather than just one magma chamber underlies the ridges:
A
Gabbro thickens at transform faults
9
Q
Based upon trace element chemistry, magma feeding ridges is thought to originate in the:
A
Asthenosphere
10
Q
What is not true of subduction zones?
A
The subducting plate melts
11
Q
What is the name of the circum-equatorial seaway formed in the cretaceous?
A
Tethys
12
Q
Which did not play a role in producing glaciers near the artic and cooling the earth from the cretaceous Hot house:
A
Freezing of sea ice
13
Q
A geoid is surface of____
A
Equal gravity
14
Q
Earth’s shape causes variations of the radius at different _______
A
Latitude
15
Q
The free air anomaly corrects for ________ between the measurement and the geoid.
A
Distance
16
Q
The Bouger anomaly corrects for _____ between the measurement and the geoid
A
Mass
17
Q
What are the 3 major earth layers?
A
-crust
-mantle
-core
18
Q
What is the boundary (discontinuity) of the crust to mantle?
A
Moho discontinuity
19
Q
What is the boundary (discontinuity) of the Mantle and core?
A
Gutenberg discontinuity
20
Q
A tectonic plate is _____
A
A piece of lithosphere that moves as a unit
21
Q
What are the three Types of plate boundaries?
A
-Convergent
-Transform
-Divergent
22
Q
Sediment deposits______ Moving away from the ridge, Why?
A
Thicken, There is more time for sed to be deposit
23
Q
Crustal depth _____ moving away from the ridge. Why?
A
Increases, As it cools it becomes more dense
24
Q
Age of crust _____ away from the ridge.
A
Increases
25
Why is there positive gravity value on the right side (under the island arc)?
There is a plate under the top plate which means it is pushed up
26
Why is there a negative value at the trench?
There is more water and sediment instead of crust
27
Why is the positive gravity value at the left side (Opposite side of the arc)?
Its getting pushed up because this is the plate going under
28
What is the rock type and structure of the oceanic lithosphere layers in order?
1. Top - Basalt (Pillow Basalt)
2. Middle - Gabbro (Layered at bottom)
3. Bottom - Peridotite (Layered at top)
29
What landform does rifting have?
rift lake
30
What landform does Young ocean have?
Mid - ocean ridge
31
What landform does mature ocean have?
Mid - ocean ridge
32
What landform does subducting have?
-Mid - ocean ridge
-Trench
-Mountains
-Volcano
-Island arc
33
What landform does closing have?
-Trench
-mountains
-volcano
-island arc
34
What landform does collision have?
Mountains
35
What is the chemical formula for decomposition?
C6H12O6 + 6O2 = 6CO2 + 6H2O + energy
36
The carbonate compensation depth is below which:
Carbonate dissolves faster than it is produced
37
For fleshy organic, explain why is was greater in the cretaceous compared to today?
Slower turnover rate, allows more time for decomposition, uses more oxygen
38
For carbonate (Shell) deposition, explain why its less in the cretaceous compared to today?
Slower turnover rate, allows decomposition, produce build up od CO2
39
Explain the BLAG hypothesis and how it causes cooling of the atmosphere
Less spreading rate, less volcanism
40
Explain how creation of mountains cools the atmosphere
New surface to weather, take CO2 and moves it to the bottom of ocean
41
Which drives ocean currents to sink?
-Colder water temp
-Greater salinity due to sea ice formation
42
What is the basic unit oxygen isotopes is?
stage
43
Unconformities can result from:
Erosion and Non deposition
44
Which clay indicates formation in warmer climate?
Kaolinite
45
A biozone may be slightly inaccurate due to:
-Emigration
-Immigration
-Extinctions are not instantaneous world wide
46
What is not a property of a good index fossil?
Occurred over a long time range
47
Which provides the least info about the age of a sedimentary layer:
Lithostratigraphy
48
What is the unconformity formed by an erosional surface between parallel sedimentary layers?
Disconformity
49
Which is not true about optically stimulated luminescence dating
Overtime, radioactive decay causes neutrons to move into the traps
50
What type of decay particle is produced by 2 protons and 2 neutrons emitted?
Alpha
51
What sediment type does gravity flows down the slope/rise?
Turbidites
52
What sediment type does wind have?
Ocean seafloor clay
53
What sediment type does meteorites have?
Tektites
54
What sediment types does volcanoes have?
Tephra
55
What sediment type does icebergs have?
Dropstones
56
What sediment type does organic-rich sediments have?
Sapropels
57
Define the term stratigraphy
Study and correlation of layered materials
58
oozes are sediments of at least ____ % skeletal remains of pelagic organisms
30
59
What are three producers of siliceous oozes?
Diatoms, Radiolarians, silicaflagelates
60
Explain how turbulence is maintained in a turbidity current?
The body moves faster then the head because the head has friction w/ the water so the body crashes into the head creating turbulence
61
The lysocline is:
Where carbonates starts to dissolve
62
The CCD is the depth below which:
Carbonates dissolves faster than it can accumulate
63
List the 3 major carbonate ooze producers in order from shallowest to deepest and explain the cause for the differing depths of each lysocline
-Shallowest: Pteropods (
-Middle: Forams (
-Deepest : Cocolithophores (
64
The suess effect is caused by?
Change in isotopic composition of atmosphere carbon dioxide
65
The DeVries is caused by?
Anomoly on global scale in the Carbon 14 dates of tree rings
66
To correct for these effects, list three data sets by which 14C ages are correlated with calendar years:
1. Tree rings
2. coral rings
3. Varvels
67
Why do basalts on the seafloor have more Ar present when they initially form? It is therefore not a closed system - so, how are K/Ar dates used to the seafloor?
The pressure on the sea floor does not allow the gas to release. K/Ar is used to compare to land to date the sea floor
68
What are the for laws of stratigraphy?
-superposition
-original horizontality
-lateral continuity
-Cross cutting relationships
69
Last major eustatic sea - low stand was at
20,000 ya
70
Which causes the greatest vertical eustatic sea-level change?
Changes to glacial volumes
71
Which has the longest periodicity?
Precession
72
Which stratal termination shows a sea-level rise?
Onlap
73
Which changes in isotopes?
Number of neutrons
74
Which is true of deltaic environments?
The delta front has a general coarsening upward sequence of sediments
75
As opposed to mixed energy barrier island, what is Not true of wave-dominated barrier islands:
Large ebbtidal deltas
76
Which is true of beaches?
Coarser sediment produce flatter beaches
77
Which is not a major theory for barrier island formation:
Tidal delta incorporation
78
Which processes are involved with landward migration of a barrier island?
-shoreline erosion
-overwash deposits
-Wind blown sediments
79
What are features that dissipate wave energy and funnel debris offshore along the seaward side of a coral bank?
spur and groove
80
Relative sea level change results change in:
-Tectonics
-Eustatic sea level
81
Changes in accommodation space and _____ may result in horizontal movement of the shoreline
Sedimentation
82
_____ is horizontal movement of environments landward
Retrogradation
83
______ is no horizontal movement of environments but building vertically
Aggradation
84
______ is horizontal movement of environments seaward
Progradation
85
name and describe the three main milankovitch cycles
1. Obliquity - tilt of earth axis
2. Precession - direction of tilt of earth axis and rotation of the elliptical orbit
3. Eccentricity - circular to elliptical orbital path around the sun
86
Given that Milankovitch cycles can lower insolation values, what specific seasonal condition is required for glacial advance?
Colder summers
87
What are three intertidal sediments which can identify past sea-level elevations within 2-3 m?
- Mangrove
-Stromatolites
-Marsh sediments
-coral reefs
88
When water evaporates from the ocean in the tropics or subtropics, the water vapor is enriched in _____ relative to the original water. When the resulting precipitation falls, the remaining water vapor is enriched in _____
1. 16O
2. 16O
89
Water vapor is transferred from the tropics to the poles through the hydrologic cycle, when this water vapor condenses and precipitates as snow on the land in the polar regions and later recrystallizes as ice, this _____ enriches water becomes "locked up" in the ice
16O
90
During glacial periods, O18 ratios in oceanic shells ______
Increase
91
Describe transgressive, highstand, lowstand, and forced regressive
-Transgressive: Rapid rise
-Highstand: slow rise to still stand
-Lowstand: still stand to slow rise
-Forced regressive: Fall
92
What is the difference in coastline shape between deltas and estuaries?
-Deltas: protruding seaward
-Estuaries: Flooded river valley landward
93
How does bottom friction modify the delta front sand bar and channel?
bottom friction causes a more rapid slowing, depositing coarser material more landward; shallow seafloor forces water to spread laterally, sediment deposition forms a taller bar and as a result of widening flow sediment forms a wider bar, the tall bar causes the water to diverge, forming bifurcating channels
94
What are two processes which increase mud deposits in the central part of an estuary?
-Flocculation
-Turbidity Maximum
95
What are the different stages of the cycle of a delta lobe?
1. Delta aggradation
2. Progradation
3. capture of other channel
4. beach
5. barrier island
6. shoals
96
Why did most of the major deltas form around 7000 years ago?
sea levels stabilized after the last Ice Age, allowing river-borne sediments to accumulate and form deltas
97
Explain why mixed barrier islands have a drumstick shape. identify the processes and geomorphic features.
1. ebb delta formed by tides
2. wave refraction around shallower ebb delta;
3. reversing of the dominant longshore current direction;
4. deposition producing ridges at the updrift end of the island
98
While many barrier islands today are retrogradational, why can a progradational barrier island form during the current rising sea level?
Sea level is slow enough that it has time to build
99
There are no tidal barrier islands because the tides produce ridges that are ______ to the shoreline
Perpendicular
100
What was used to accurately measure sea level chnage during the last 150 year period?
-Tide stations
-Satilites
