Final Flashcards
1
Q
feedback
A
forcing like variations in solar radiation, increased volcanic activity can cause climate change
2
Q
What magma/melt generation does continental rift use
A
decompression melting
3
Q
Physical appearance of lava domes
A
dome feature- plugging of vent due to high viscosity
small to moderate in size
4
Q
Whan can precede a volcanic eruption
A
Seismic activity increases
increased gas activity
change in topography
change in temp
5
Q
Bioturbation
A
Reworking of soft sediment by burrowing organisms
SHALLOW MARINE environments
Used to indicate WATER DEPTH
6
Q
Schistosity
A
Term for coarse grained, visible, platy minerals in a planar fabric, typical of schists.
7
Q
Lineation
A
Refer to elongated linear minerals (longer in one direction) that are aligned within a rock
NO orientation into planes
8
Q
What are the two main contributors to sea level rise as climate warms?
A
Melting of glaciers and sheet ice
Changes in ocean circulation- thermal expansion
9
Q
Why does contact metamorphism produce only non-foliated metamorphic rocks?
A
No pressure that foliated one need
10
Q
metamorphic grade
A
range of metamorphic change a rock undergoes, progressing from low (little metamorphic change) grade to high (significant metamorphic change) grade.
11
Q
What are the components of Earth’s system?
A
Sum of physical, chemical, and biological processes operating on and within the Earth
Geosphere, Atmosphere, Biosphere, Hydrosphere, Cryosphere
12
Q
Trace fossils
A
Evidence of ancient organisms behavior
Indirect evidence of past life
Represent activites of organisms while it was alive
Footprints, burrows, tracks, trails, boring, bite marks, skin impression
13
Q
Magnitude- shaking
A
Larger MW< the stronger and more time the shaking occurs
14
Q
What does the magnitude of earthquakes refer to?
A
Refers to amount of energy released
Earthquake has ONE magnitude (QUANTITATIVE)
15
Q
Why is our current climate change so concerning, when climate has changed many times in Earth’s history?
A
It is warming at an accelerate rate than what it should be
16
Q
Euhedral mineral tells what of the environment
A
well-developed, has room to grow
17
Q
Protolith
A
The rocks that existed before the changes that lead to a metamorphic rock
18
Q
Heat induced Melting
A
INCREASE in temp
melting of surrounding rocks from magma intruction of rising mantle plume
MANTLE PLUME
HOTSPOT
19
Q
Know when the Great Oxygenation Event and the Second Oxygenation event occurred.
A
Great Oxygenation- 2.4-2.3 Billion years ago
Second Oxygenation- 0.7-0.6 Billion years ago
20
Q
Material of Rock Cycle
A
Igneous Rocks, sedimentary rocks, metamorphic rocks
Sediment and magma
21
Q
What are the correlation techniques we went over in lecture?
A
Lithostraigraphic
Stratigraphic
Chronostratigraphic
Biostratigraphic
Magnetic Polarity Reversals
22
Q
Core
A
Directly below mantle
upper and inner
upper is liquid iron
inner is solid iron
23
Q
What is elastic rebound theory?
A
Bending of rocks near fault reflect build-up of stress
When stress is greater than frictional resistance of rocks- rocks rupture- slip along fault
After eaerhquake, continuation of stress occurs, causing elastic energt to build back up
24
Q
brittle deformation
A
rock integrity fails and the rock fractures under increasing stress
25
What type of fault does mid-ocean ridge spreading centers use
Tensional, Normal faults
26
Negative Feedback
suppress/reduce the original cause/effect
27
What played a role in global cooling trend in the Cenozoic?
Anarctic Circumpolar Current
28
Continental collision
two continental plates collide- no subduction
29
What causes the seasonal variations/ fluctuations between seasons?-- CO2
Summer- consume CO2- plants photosynthesis
Winter- release CO2- plants die
30
Why is carbon dioxide the most important GHG?
Longest residency time in atmosphere
Up to 1000 years (methane only 12)
Lower GWP (global warming potential)
Largest anthropogenic emission
31
Native Minerals
atoms of one element
32
Asthenosphere
base of lithosphere to 410-660 km down
weak, solid but flows
what tectonic plates are on top of
33
Disconformity
Erosional surface between sedimentary rocks
Deposition of rocks, uplift of rocks, substance and deposition, order
34
Which type of metamorphism occurs at a relatively low temperature and high pressure environment, and the diagnostic metamorphic rock is blueschist.
subduction zone meta
35
Outer core
Liquid iron
Earth's magnetic field
36
Foliation Texture
A planer alignment of minerals and textures within a rock
Line on plane with no common direction
37
Principle of Original Horizontally
Sedimentary layers (strata) were deposited nearly horizontally and parallel to the earth's surface
over time, layers can be tilted, folded, or both
38
What is albedo and how can it affect climate change?
When ice/water reflect sunlight back to atmosphere, decreases global warming, less energy that the surface air and ocean absorbs
39
Subduction
plates of different densities converge, higher density is bushed beneath more buoyant plate
40
What metamorphic rocks are diagnostic of subduction metamorphism?
Greenstone, greenschist, blueschist, eclogice
41
How do hotspots form
mantle plume is stable, but plate itself moves, creates volcanic island. as plate moves, island source is cut off and starts to cool down and sink. Plume creates another one, cycle
42
carbonate minerals
calcite, dolomite, malachite, polomite
43
Lacustrine
Continental- Lakes
Low energy environment
Main sediment- fine-grained
Main rock- shale
Main structure- lamination
Main fossil- freshwater organisms
44
What type of fault does continental rift use
Tensional, normal faults
45
Divergent boundaries types
COntinental rift and Mid ocean ridge
46
Mantle
Below crust
2900 km depth
made up of periodite- mostly solid rock
flows as weak solid- some molten
47
What was the importance of the development of the Antarctic circumpolar current in the Cenozoic?
Started the global cooling trend
Allowed it to flow unrestrictedly- isolated it from the warmer waters- cooled and glaciers started to form
48
Observation
comment/statement about what you see/percieve
49
Pollen proxy
Pollen grains on distinctive among different plants
Can use pollen found in ancient sediment and sediment per to induce different climate and environments
50
What is earthquake intensity
Intensity is a measure of the amount of ground shaking at a particular site
Determined from reports of human reaction to shaking, damage done to structures, and other effects
Intensity varies with distance and is an ovservation (QUALITATIVE)
51
Burial Meta
Rock deeply buried 7200 m
Deep sedimentary basins
Extension of diageneis
Increasing temp, CONFINING pressure at depth- low grade- zeolic facus
Quartz sandstone- quartzite
52
Negative Feedback Examples
Increase in CO2-> promotes forest growth, increase CO2 drawdown by photosynthesis= lowers GHG and air temp
Increase in atmospheric CO2-> increase carbonic acid in rain= increase chemical weathering= more CO2 stored in ocean sediments lowers CO2 ending up back in the atmosphere
53
6 different types of volcanoes
Cinder/Scoria Cones
Shield Volcanoes
Stratovolcanoes
Lava Domes
Calderas
Flood Basalts
54
What does presence of coarser vs finer clast size indicate about energy of envionment and distance
coarser- high energy- small distance
finer- low energy- long distance
55
Physical processes metamorphism
Deformation of objects
Rotation
Shearing
56
Difference between confining pressure and directed stress?
Confining
Same amount of stress from all direction
Uniformly distributed- all rocks
Directed
Different amounts of stress from different direction
Unequal distribution
Modifies the parent rock at mechanical level, crates identifying textures- change arrangement, size, or shape of crysalts
57
rift valley
area of extended continental lithosphere, forming a depression, can be narrow or broad
58
relationship between cooling rate and mineral crystal size (igneous)
faster cooling rate means smaller crystal size
slower cooling means larger crystal size
59
Dunes
Meter Scale Ripples
60
What are sheet silicates
Micas
61
Proxy data
fossil identification, stable isotopes, cyclical features
62
Mesosphere
base of asthenosphere to core boundary
more rigid and immobile that asthenosphere
63
Euhedral
perfectly shows its true crystal habit
64
Hypocenter/focus
Where earthquakes is generated, point of origin
65
What are transport pathways
Are mechanisms/processes that make elements between the reservoir
Process: evaporation, precipitation, respiration, transportation, chemical weathering, volcanic organism, photosynthesis
66
MOR metamorphic process
NORMAL faulting, down-dropped fault blocks
CONTACT metamorphism and HYDROTHERMAL chemical alteration
67
Mid-Ocean Ridge- earthquake
Characterized by shallow, small magnitude earthwauke
Because crust is hot and very thin- not large or deep earthquakes
68
relative dating
putting events in order based on relative positions to other geologic features
key relationship principle- sequence of events
69
Subduction Zone- earthquake
characterized by shallow to deep, small to large earthquakes
Largest and deepest earthquakes occur along subduction zones
70
Varves dating
Alternating light and dark layers of sediment due to seasonal variations of sedimentary and biological activity
Light layers- sand and silt during summer
Dark layers- mud during winter
Varves deposit record thousands of millions of years timespan
71
Contact meta
High temp low pressure
Local, small instruction
Shallow depth
Produce NON-FOLIATED rocks
Heat from magma alters rok in comes in contact with (heating, NO deformation)
72
Continental red beds- oxidation
Well-oxidized, iron bearing sediments
Appearance in rock record after 2.3-2 billion years
73
conglomerates
coarse clasts
rounder grains than breccia
poorly to moderately sorted
sand and/or mud matrix
74
What magma/melt generation does transform boundary use
no magma formation
75
Transgressions
Rise of sea level and submergence of the continent under seawater
Depositional environments shift landwards (go further towards land, ocean expanding)
76
What three factors determines the amount of destruction?
Building Materials
Intensity and Duration
Resonance
77
Fractionation
Magma composition erodes as mienrals crystallize out- remaining melt becomes silica rich and felsic
mafic to felsic
78
Are earthquakes in mid-ocean ridge settings typically deep or shallow, strong or weak? And why is that?
Shallow, weak
Because crust is hot and very thin- not large or deep earthquakes
79
What is stick-slip behavior?
Rocks are resistant to movement, when stress gets too much for rocks, they slip- faults rupture
When slip, release energy in form of earthquake
Stress increase, and experience elastic strain
Fault slip b reaking rocks, causing earthquake
Cycle starts again
80
how valence electronegativity affect covalent and ionic bonds
Covalent- elements with similar electronegative combine
ionic- elements with lower give up, higher ones gain, combine
81
What is the Cambrian explosion?
Refers to sudden appearance of numerous and diverse complex marine animals with mineralized skeletcal remains in fossil record
82
Three ways magma can form
Decompression Melting
Flux Melting
Heat Induced Melting
83
Decompression Melting
lowering of Pressure WITHOUT changing the temperature of his rising mantle material
DIVERGENT boundaries (MOR, continental rifting)
HOTSPOTS
84
What is the difference between normal and reverse faults?
Vertical motion, hanging wall movesa DOWNWARD relative to footwall
Reverse- compressional stress, vertical motion, hanging wall moves UPWARD relative to footwall
Thrust- lower angle reverse faults (less than 45)
85
What directed stress commonly formed folds?
Compressional
86
compaction
pressure of overlying sediments decrease pore space between the grain
87
halides elements
halite, Flaurite
88
Difference between Volcanic island arcs and volcanic island chains
Volcanic island arcs- made from subduction (have to do with plate boundaries)
VOlcanic island chain- formed over hotspot
89
How does viscosity and gas influence eruption stlye
High gas- more explosive
High viscosity- stops more gas from escaping- more explosive pyroclastic
90
Principle of Superposition
in undistrubed succession of strata, the oldest layers are at the bottom, successively younger layers above
91
protolith for greenschist
greenslate
92
Magnetic Polarity Reversals
Matching normal and reserval periods recorded in the rocks
93
Physical appearance of Flood Basalts
large igneous provinces
multiple explosive centers from fissured dikes
94
Extrusive igneous rocks
volcanic
magma erupts ABOVE earth's surface as lava, melts, and solidifies above surface
lava flow and pyroclastic deposits
95
Sandstone
sand lithified to sandstone
coarse grains
wide variety of mineral grains
grain roundness varies
moderate to well sorted
96
what are 4 common GHG?
Water vapor
Nitrous oxide
Methane
Carbon Dioxide
97
What role did cyanobacteria have in the oxygenation of Earth’s atmosphere?
Algae added oxygen via photosynthesis
98
Nonconformity
Erosional surface between sedimentary rocks and crystalline rocks
Nonlayered rocks uplifted and eroded, erosional surface buried by sediment
99
Glacial
Glaciers expand, forming a new reservoir of isotopically light water on the land; sea level drops and the ocean becomes isotopically heavy
100
3 major rock categories
Igneous
Sedimentary
Metamorphic
101
What event defined the Precambrian Eon-Paleozoic Era boundary?
Cambrian Explosion
102
Shield volcanoes have low slopes primarily because
the low viscosity of basaltic magma allows it to flow downhill for long distances.
103
What are climate proxy indicators?
Biological, chemical, or physical signatures preserved in rock, sediment, or ice records that indirectly call past climate conditions
104
Climate
Variable range of temperatures and precipitation patterns averaged over the long term for a particular region
105
O-O subduction
older, colder plates move under warmer younher one
volcanic island arc
106
What does low vs high grade metamorphism indicate?
Low – finer grained crystals
High- coarser grained crystals
107
What are the Milankovitch cycles? How do they influence Earth’s climate?
Earth’s orbit variations around the sun
Orbital movements- Eccentricity, obliquity, precession
3 variatiosn combine to vary the amount of solar radiation (heat) that Earth receives
Directly influence Earth’s climate over long timespans (10s-100s of thousands of years)
108
What are consequences of climate change mentioned in lecture?
Change in Ocean Circulation
Sea Level Rise
Temperature Change
Distribution of plants, animals
109
Chalk is considered a biochemical sedimentary rock because
It's a carbonate that formed from the calcium-rich skeletons of microorganisms that had accumulated on the seafloor
110
Physical appearance of Cinder/Scoira cones
smallest volcanoes
conical, steep, symmetric sides
111
Focus Depth - shaking
A deeper focus= less surface shaking
112
Metamorphic rocks
Rocks that are formed by chemical and/or physical textual alterations of pre-existing rocks from temperature and/or pressure changes
113
Mid-Ocean Ridge
Oceanic lithospheric late moves away from each other, widening of ocean crust, new oceanic crust forms
rift valley is center (spreading center) mantle upwells- decompression melting
114
Local Geological Conditions: Substance Material - shaking
Seismic waves travel slower in unconsolidated material like sediment- increase surface wave motion and shaking
115
Know the percentage of radioactive isotopes (parent atoms) that are left in a sample after: 1 half-life, 2 half-lives, 3-half-lives
1 half life- 50
2 half life- 25
3 half life- 12.5
116
How does crystal size and metamorphic fabric (foliation degree) relate to metamorphic grade?
Smaller crystal size- low
Bigger crystal size- high
Foliation- high
Non-foliation- low
117
How is magma caused in divergent boundaries
decompression melting
118
strengths of the bond
Order of strongest to weakest
covalent, ionic, metallic, Inter.Mol. attr.
119
Qualitative
Description, observation, based on numerical data
( words, sketches, images)
120
Great Dying Extinction
Boundary- Paleozoic and Mesozoic- 252 Million years ago
Earth’s deadliest mass extinction – 96% all life
Causes- combination of changes
Volcanic activity in Siberia and China= Siberian Traps, massive amount of CO2 in atmosphere
Sea level dropped- reduce area of shallow seas
Aridity on continents increase- drying out
Meteroite impact
Deep sea Anoxia
121
Sheet silicate
Micas- silica tetrahedron share bottom 3 oxygen atoms, one left in corner, bonded weakly to other sheets
122
Transform boundaries
fault of these called strike slip fualt
crust is deformed
no volcanoe, lot of earthqyake,
found along mid-ocean ridges
123
what defines Sulfates
sulfate tetrahedron (SO4)
124
Magma compositions of Flood Basalts
low viscosity
Basalt lava flows
125
mineral cleavage
mineral breaks along a plane of weakness
126
Rules that a mineral must meet
naturally occurring
inorganic
crystaline internal structure
solid crystalline substance
defined chemical composition
127
cementation
precipitation of minerals from water within pore spaces bind grain together
128
What are the two non-anthropogenic ways the carbon cycle can be unbalanced?
Long periods of above-average volcanic activity
Siberian and Deccan Traps (Flood basalts)
Significant mountain-building events= increased rocks being weathered
Himalayan Mountains
129
Partial Melting
different minerals make up rocks, minerals melt at different times
Resulting melt more felsic
increase from ultramafic to mafic- felsic melts from rock sooner
130
What are the different unconformities
Angular unconformity
Nonconformity
Disconformity
131
What type of fault does Transform boundaries use
shearing, Strike-slip faults
132
ductile deformation
plastic deformation that produced folds, irreversible but does not break the rock
133
what defines Halides
halogens
134
What four factors determines the amount of shaking an area experiences from an earthquake?
Magnitude
Location and Direction
Local Geological COnditions: Substance Material
Focus Depth
135
Banded Ion Formation
Increase in oxygen cause dissolved iron to deposit on ocean floor
Found in rocks 3.6-1.9 Billion years ago
136
Isostasy
Relationship between crustal thickness, density, and elevation
137
Ice cores (bubbles)- proxy
Chemistry of trapped gases (ancient atmospherically CO2) in ice layers revelas the comp of the atmosphere over the past 800,000 years
Oxygen isotopes from annual ice layers, ratio of 180-160 uses to determine temp
138
Schistosity is an example of which type of chemical or physical metamorphic process?
Rotation
139
Primary Wave
Compressed material in direction of propagation
Fastest wave
140
What is used to classify igneous rocks
Texture and composition
141
most common rock forming mineral group- why
silicates
most abundant elements in Earth's crust are silicon and oxygen
142
Vesicles- what does it indicate
pressure gas bubbles
magma is gassy- explosive
143
Beach
Transitional
Important transport process- wave and tidal current
Main sediment- sand
Main rock- sandstone
Main strucute- plane bed, large cross beds
Constant wave activgity, little to no structure preserved
Main fossils- bioturbation, marine invertebrates, rare vertebrates, some corals
144
What are the two processes of lithification
cementation
compaction
145
As magma cools minerals crystallize out causing a change in the remaining magma composition. What is this process called?
Fractional crystallization
146
What are two types of body waves
P-Wave (Primary)
S- Wave (Secondary Body Wave)
147
Mudcracks and raindrop impressions
When wet-logged clay rich sediment dries out
Shrinking mud forms cracks- get preserved if sediment fills in cracks
Can form TIDAL FLATS; DRIED LAKES: SHORELINES
148
Isotopic minerals dating
4.5 Billion
dated moon rocks
oldest dates on Earth's rocks
149
Why do seismic wave paths curve through the earth?
Rocks get denser deeper in the Earth
Waves paths permit us to find depth to crust mantle boundary
150
What are the three lines of evidence that provide the age of the Earth?
Isotopic minerals
Radioactively unstable isotopes (decay rates)
Other methods- tree rings, ice cores, varves
151
Diverge plate movements
Away from each other
152
Carbonization
Organisms get compressed and only carbon preserved: carbon silhouette
153
Uniformitarianism
Process at work today is same as how they were in the past
154
what controls magma viscosity
Magma Composition and temperature
155
internal atomic arrangement
proton and neutron in nucleus in middle, electron outside
156
5 different types of metamorphism
Contact
Regional
Subduction Zone
Burial
Fault
157
What are the two main evidence for the formation of Earth crust in Earth’s very early history?
Greenstone- metamorphed lava rock- magic
Shattered rocks from impacts
158
Mudstone (siltstone/claystone)
fine grained
silt lithified to silt
clay lithified to clay
159
Continental Drift Hypothesis
continents were originally connected and then drifted apart
160
Know the sense of slip (vertical or horizontal) between dip-slip and strike-slip faults.
Dip Slip is vertical
Strike- slip horizontal
161
Major defining Characteristic of Divergent boundaries
crustal strething- creation of new crust
162
Change in ocean circulation
Ocean current influence climarte of a region and transfer warmed equalatorial water to colder poles
Surfrace current driven by wind
Ocean conveyor belt (surface and deep oceanv current) driven by density: salinity and temperature
Change in conveyor belt due to
* Influx of freshwater
* Warming temperatures
163
What makes radiocarbon dating different from other radioisotope decay series such as U-Pb, K-Ar?
Radiocarbon dating- 5730 years, used on material no older than 60,000 years
Used on organic matter
Other ones are much longer
164
What are the ways fossils can be preserved
Permineralization
Casts or molds
Carbonization
Unaltered Remains
165
If you were shown a figure of earthquake hypocenters indicating a trend of shallow to deep hypocenters- what would you be able to infer? What would the trend indicate?
Subduction zones, slabs got subducted
166
Physical appearance of stratovolcanoes
distinct crater at top
rise high above landscape
snowcapped and steep symmetrical flanks
167
Difference in relative to absolute dating
one is based on sequence of events
assigning an age in years
168
Transform plate movement
plate boundaries move horizontally past each other
169
Know the order of seismic wave arrival recorded by a seismograph for P-waves, S-waves, and surface waves.
P-Waves, S-Waves, Surface Waves
170
Igneous rock
formed from crystallization and solification of magma or lava
171
Bowen's Reaction Series
The concept that describes the crystallization order of silicate minerals in melt related to temperature
172
Intraplate- earthquake
In areas of weakened crust or contentrated tectonic stress
173
Why was continental drift hypothesis rejected
not explain mechanism of how continents moved apart
174
metallic bonding
sharing of electrons between many atoms- loosely connected to nucleus
175
Interpretation
logical scientific interference based on observation and numerical data and prior knowledge
176
Which clastic sedimentary rock would be more likely deposited in a low energy environment?
mudstones or shales
177
Non-Foliation Texture
Metamorphic textures that do not have a directional component of its minerals
178
Breccia
coarse angular clasts
poorly sorted- large boulders to fine sediment
clasts of different rock types or all same type of rock
179
Order of Sedimentary rock process in rock cycle
Weathering (mechanical and chemical)
erosion, transport, deposition
Burial
lithification, diagenesis
180
Who proposed Continental drift hypothesis
alfred wegener
181
Magma compositions of Cinder/Scoira cones
low viscous lava
mafic lava with high volatiles (gassy)
182
Stromatolites
Flat or hemispherically laminated structured of fine caebonate, fine organic matter, and clay/silt
Formed by trapping and binding of cyanobacteria
Formed today by mainly in shallow tidal zones
Oldest fossil
Occur in carbonate limestones
183
Mesozoic- organisms known for
Dinosaurs and flowering plants
184
Low oxygen environment fossil
Slow decay, no bacteria or organisms that require oxygen
185
Sea level rise
If all land ice melted, estimated 216 ft rise in sea level
186
Clastic sedimentary rocks are classified (dominantly) based on what?
grain size
187
oxide minerals
hematite, magnetite, bauxite
188
peat
partially decayed vegetation or organic matter converted into carbon-rich coal under high temp and pressure
189
Chemical Sedimentary rocks classification
organic
inorganic
biochemical
190
Precambrian- organisms known for
Simple creatures and fossils- stromatolites, cyanobacteria
191
What metamorphism occurs along continental collision settings? (choose all that apply)
regional metamorphism focued within thrust sheets
192
ionic
transger electrons
193
Flux melting
Addition of volatives allows rock to melt at lower temp
NO change in temp or pressure
SUBDUCTION ZONES
194
Evidence to Continental drift hypothesis
COastlines of continents fit together (continental shelves)
Similar rocks, mountains, fossils, and glacial formation across oceans
Glaciers in tropical places and tropical plants in arctic places
195
what are magnetic stripes on seafloor and how are they formed
formed by when magma cools, iron bound minerals align themselves with Earth's current magnetic field
represent changes in dirextion of magnetic poles
196
Inner Core
Pressure too intense, iron ins solid
197
sulfides minerals
galena, Pyric (fools Gold)
198
what tectonic setting uses decompression melting
Mid-Ocean Ridge
Continental rift
(Divergent boundary)
199
What is the evidence of our recent climate change?
Changes in weather patterns, changes in frequency or strength of severe storms
Iuncreased air temp- greater moisture capacity of atmosphere= increasing potential for more extreme events
Extreme weather events increasing
Increased atmosphere carbon dioxide
200
Regional Meta
Alteration of rock by increase temp with high pressure (heating AND deformation)
Wide range in depths, temperature, and pressure
Distributed through wide geographic area
Caused by lagsacre geologic processes (mountain- compression)
Regional produced FOLIATED rocks
201
Resonance
Seismic wave frequency matched a building’s natural shaking frequency- increased shaking
202
What are the six key principles of relative dating
Principle of Superposition
Principle of Original Horizontally
Principle of Lateral Continuity
Principles of Cross Cutting Relationships
Principles of Inclusions
Principles of Fossil Succession
203
Non-foliated metamorphic rocks form by which metamorphic process?
Recrystallization
204
K-T Extinction
Boundary- Mesozoic to Cenozoic
Dinosaurs extinction
Causes
* Dinosaur population already declining
* Deccan Traps- extensive volcanic activity
* Changes in continental configuration and ocean circulation
* Global temperature falling
* Sea level drops
* Impact of Chicxulub meteorite
o Shocked quartz
o Concentration of Iridium layer
o Crater size of impact
205
Assimilation
incorporates the host rock that magma is intruding into
piece of surrounding block gets added to melt/magma, pieces partially melt
206
Protolith for marble
limesotne
207
Anticline
arch like- A shaped- folds that are convex upward
Downward curvling limbs that dip down and away from central fold
208
Graded Bedding
Change in grain size within a sediment bed
Trends from coarse to finer; or finer to coarser
Caused by changes in currents speed
Events like FLOOD, LANDSLIDES, SUBMARINE LANDSLIDES
209
ways to atoms can bond to form minerals
covalent
ionic
metallic
inter-molecular force bonding (Van Der Waals)
210
Chronostratigraphic
Use of absolute dating methods to match rocks of the same age even though made of different lithologies
Different lithologies of sedimentary rocks can form at same time at different geographic locations between depositional environments vary geographically
211
Types of Subduction
Oceanic-Oceanic
OCeanic-Continental
212
Viscosity
resistance to flow
213
Tree Rings proxy
Annual tree rings can vary in width dependent on conditions, variations in precipitation, temo
Narrower rings indicate colder and drier climate
214
Synclines
trough-like, U shaped, folds that are concave up (like cup)
beds dip down and toward central fold
215
Principles of Cross Cutting Relationships
Rock unit, sediment body, or fault that cuts another geologic unit is uounger than the unit that was cut
Youngest feature cuts older features
216
Unaltered Remains
Freeze-dried; pickled in tar; amber encasing
217
Sediment cores and oceanic microfossils proxy
deep sea sediment indirect indicator
chemical records of stable oxygen, carbon, boron isotopes
O isotopes is fossil microorganisms shells
218
Special properties of minerals
magnetism
dendity (specific gravity)
efforescence (acid test)
fluorescence
219
Clastic Sedimentary rocks classification
Breccia
conglomerates
sandstones
mudstone
shale
220
what tectonic setting uses Flux melted magma
O-C subduction
O-O subduction
(subduction)
221
What tectonic settings use tensional, normal faults
Continental rift
MOR spreading centers
(Divergent)
222
In what environments does low pressure/high temperature metamorphism occur
near magma intrustion at shallow depth
223
Temperature Change
Some regions getting colder and others warmer
224
Continental Rifts Meta process
NORMAL faulting, down dropped fault nlocks
CONTACT metamorphism; SHEARING along deep faults, HYDROTHERMAL chemical alteration; BURIAL metamorphism
225
What tectonic settings use Compressional, Thrust/reverse faults
Subduction (convergent boundaries)
Continetal collision
Convergent boundaries
226
Halides
Halogens
evaporation and precipitation
227
What do unconformities indicate in the rock record
period during which deposition did not occur or erosion removed rock that had been deposited, so there are no rocks that represent events of Earth’s history during that span of time at that place
228
native elements examples
gold, silver, copper
229
types of convergent boundaries
Subduction and continental collision
230
Biochemical
formed from shells/skeletons of marine/freshwater organisms
Organisms extract dissolved material out of water to form shells, when dies, the hard parts deposit on sea floor as sediment that lithifies when buried
fossiliferous limestone
chalk
biogenic chert
stromatolites
231
Transform Boundaries
FAULT metamorphism- strike-slip faulting
232
Strike Slip Faults- stress and plate tectonic
Side-to-side motion – areas of compression or tension
Transform plate boundaries
233
What is a seismic gap? What does it indicate?
When and where earthquakes occurred in the past
Determine locations and recurrence intervals
234
Angular unconformity
Erosional surface with flat/horizontal rock layers above and tilted rock layers below
235
Major defining Characteristic of continental collision
Convergent boundary
tall broad mountains
little volcanism
broad zone of frequent earthquakes
236
Hard parts- fossils
More difficult to break down or less likely to be eaten
237
Eccentricity
shape of Earth’s orbit- 100,000 years- 413,000 years
238
Anhedral
shows no crystal habit
becuase not prone to habit or grew in way that it was confied and oculd not grow normally
239
What is stratigraphic correlation?
Uses straitigraphic relationships between strata that are located in distant geographical areas to determine which are the same age- matching sequence of rock formation
240
Inorganic Sedimentary rocks high evaporation rate
cause bodies of water to dry up
Dissolved ions precipitation out of solution
Forming evaporate minerals
Salt, calcite, gypsum, halite
241
names of common rock forming mineral groups
Silicates
carbonates
oxides
sulfides
sulfates
halides
phosphates
native minerals
242
importance of radioactive isotopes
Each radioactive element decays at a predictable constant rate that is uniwue to that element- can tell how old element is by how much parent isotopes are left
243
Biostratigraphic
Use of index fossils to determine the age of the rocks that fossils are found in
Represent single group of orfganisms that were uniquely present during specific intervals of geologic time
Most useful index fossils have short age span, widely distributed, abundant, and distinctive
244
Principle of Lateral Continuity
Strata layers are continuous in all directions until they thin out at the edge of that basin
245
Location and Direction- shaking
Distance from Epicenter, path of rupture propagation
246
recurrence interval
average time between repeating earthquake- varies based on fault
247
phosphates minerals
apatite
248
What are the three factors that help the chance of fossil preservation which we went over in class
Hard parts
Rapid Burial
Low oxygen environment
249
What type of heat does GHGs trap?
Thermal IR
NOT UV light, visible light, or IR
250
what are different types of sedimentary structures
Bedding planes
Laminatiosn
Graded Bedding
Bed Forms
Cross Beds
Bioturbation
Mudcracks and Raindrop impressions
251
What does grain size, sorting, and clast shape indicate and environemtn distance
grain size- as size gets smaller, longer transport time
sorting- more well sorted the rock is, longer the distance
shape- rounder (smoother) it is, the longer the distacance
252
what defines silicates
silicon tetra-hedral (SiO4)
253
Know what are the two likely causes of the extinction of the last ice-age Megafauna during the Cenozoic
Overkill hypothesis
Humans killed them
Climate change hypothesis
254
half life
Each isotope gradually decays to form a new isotope, after one half life, 50 percent of parent life remains
255
Mudstone
general term for fine grained sedimentary rocks
256
Regression
Drop of sea level and withdrawal of water from the land
Depositional environments shift seaward (go towards sea, ocean regressing)
257
Fluvial
Continental- Rivers
High low energy, water transport
Meandering and braided rivers
Meandering- 1 single channel
Braided- multiple channels
Main sediments- sand, mud, coarse grains
Main rocks- sandstone, conglomerates, siltstone
Main structure- cross beds, asymmetric ripples, channels
Main fossils- bone beds,
258
What magma/melt generation does Mid-Ocean RIdge use
Decompression melting
259
Continental Collision Meta Process
REGIONAL and FAULT metamorphism
Focused within THRUST shets (fold and thrust belt
SHEARING< folding and strongly FOLIARED Rocks, such as slates, schist, gneiss
SHEARING along deep faults
260
Laminations
Parallel layers, less than 1 cm thick, fine grained sediments
Fine grained sediment deposited in QUIET,
LOW energy environment
Lake, deep ocean
261
Principle of Inclusions
Fragments of rock within a large rock unit are older than the rock its enclosed within
262
Convergent plate movement
move toward each other
263
sulfates examples
gypsum, epsom salts
264
carbonates
has Ca, mg, Fe with carbonate. More than 50 different types-
265
Corals - proxy
chemistry of coral growth layer is affectdd by laminations in the temp and water comp around them
The info in their layers can tell us what the local climate was like at the time they were created
266
Effusive Eruption
Non-explosive eruptions
low gas and low viscosity
lava dome and lava flow
267
evidence for seafloor spreading and age of ocean crust
Magnetic stripes of floor
ocean drilling
GPS measurements
ocean trenches, lined up earthquakes, GPS measurements, mid-ocean ridge, and Paleomagnetism
268
Magma compositions of lava domes
high viscosity
highly fractured solified lava (intermediate-felsic)
269
Law of superposition
in undisturbed layers of rock, oldest layers are at the bottom and youngest at the top
270
Major defining Characteristic of Transform boundaries
no volcanoes
rarely mountains
lots of earthquakes
crust deformed
271
What is the relationship between CO2 and global temperature? Do they covary? Why?
CO2 and temperature are in direct correlation
They Covary
Due to variation in solar heat from cyclical changes in Earth’s orbit around the sun (Milankovitch cycles)
272
Reverse fault- stress and plate tectonic
Compressional Forces
Convergent Plate Boundaries- Subduction
273
Processes of Rock Cycle
Crystallization
Weathering
Melting
Lithification
Change in temp and/or pressure
274
Deltas
Transitional - Where rivers enters oceans
Three types- river delta, wave delta, tide dominated delta
Main sediment: channelized sand, mud, organic matter (swamp)
Main rock- clastic rocks, coal/organic sedimentary rocks (swamps)
Main structure- cross bed, delta seidments, sequence (muds to fine sand to coarse sands and organic rich rocks)
Main fossils- many to few fossils
275
What are reservoirs
Places where elements are stocked in earth system
Ocean, lake, atmosphere, rocks, plants, animals
276
Precession
direction earth’s tilted axis (19,000-24,000)
277
What is the Paleocene-Eocene thermal maximum?
Warm period before Cenozoic cooling
40-35Ma global coolinh turned to tectonic events
278
two different types of igneous rocks
intrusive and extrusive
279
Trace and body vs indirect and direct
Indirect- trace
Direct- Body
280
How does present day CO2 concentration in the atmosphere compare to the past 400,000 years?
Current CO2 concentration is the highest it has been since 400,000 years
10x fasrer than average rate of global warming after a glacial period
281
common physical properties of minerals to help geologist identify
color, luster, streak, crystal habit
282
What causes initial magma composition to change
Partial Melting
Fractionantion
Assimilation
283
Inorganic
evaporates/precipitates from water (by chemical reactions)
Classified by composition
284
Subduction Zone
Unique: High pressure, low tempes
Slabs slow to increase in temp at depth, pressure larger affedct
Mafic oceanic lithosphere subducted and meta
Greenston, greenschist, blueschist, eclogice
285
Which type of magma is typically silica-rich felsic or intermediate in composition and produce granites, rhyolites, tuffs, and andesites?
High Viscosity Magma
286
what defines Sulfides
S2
287
elastic deformation
Strain that is reversible after a stress is released
Material that gets deformed but when applied stress is removed the material goes back to its unstrained state
288
Magma compositions of stratovolcanoes
high viscosity and silicate
felsic magma chamber
289
Absolute Dating
Numeric Method of dating a geologic material or event to a specific amount of time in past
Assigning an age in years
290
Physical appearance of shield volcano
long angles, broad flanks
small vents and craters at top
can be largest of volcano- size varies
291
Van Der Waals
produce from intermol. attraction b/w one molecule and a neighboring molecule
292
Quantitative
observations based on numericals dta using tools, instruments
293
Physical appearance of Calderas
moderate to very large circular, steep-walled depressions
294
Metamorphic textures
foliation
lineation
non-foliated
schistosity
295
Tree rings dating
Dendrochronology- dating of wooden objects by counting growth rings
Characteristics of growth rings inside a tree tell how old tree is
Extends 9000 years
296
Bed Forms
Sedimentary structures formed from a current (water or wind) working on sandy sediment
Ripples
Dunes
297
Boron isotopes
Analyze boron-isolate ratios of fossil microorganisms shell from deep-sea sediment cores
Relative abundance of Boon isotopes- 10B and 11B to sense pH
Increase in atmosphere CO2, make more CO2 absorved in ocean, carbonic acid
298
Positive Feedback
amplify/enhance the original cause/effect
299
Interglacial
Isotopiocally light water evaporates from the ocean and returns via rivers the system is in balance
300
Magma compositions of Calderas
Intermediate to felsic comp
301
What are the two main evidence suggesting that free oxygen began to accumulate in Earth’s atmosphere during the Precambrian Eon?
Banded Ion Formation
Continental red beds- Oxidation
302
Order of Bowen's reaction series
Ultramafic, Mafic, Intermediate, Felsic
303
What are the components of the biological carbon cycle?; geochemical carbon cycle?
Biogeochemical- biotic, involve organisms
Geochemical- Abiotic
304
Continental rift
continents breaking apart, crust thickening, causing faults and rift valley
mantle upwelling
narrow or broad (Garben and Horst)
305
plastic deformation
Brittle and ductile
Strain is IRREVERSIBLE
Change to rock its permanent and material is no longer able to revert to its original shape
306
Body fossils
Remains of actual organism that have been altered
Direct evidence of past life
Durable and inedible hard parts (bones, teeth, shells)
307
Shale
fissile mudstones, separated into thin sheets
308
Would you expect younger or older rocks to be in the center of a syncline or anticline?
Syncline- youngest rock is in center
Anticline- oldest in the center
309
what defines Phosphate
Phosphate tetrohedron (PO4)
310
Ground motion from seismic waves can cause what sort of hazards?
Structural damage, landslides, land elevation change, liquefaction, tsunamis
311
What is the Keeling Curve and its significance?
direct measurement of atmospheric CO2 taken since 1958
312
Scientific method steps
make observation, identify problem, and/or form a question
form one or more hypothesis
conduct experiment, hypothesis revision
peer review, publication, and replication
Scientific theory development
313
Where do earthquakes occur?
Mid-Ocean Ridge
Continental Rifts
Continental Collision
Subduction Zone
Intraplate
Transform Boundaries
314
Sulfides
sulfide bonded, metallic lust, igneous environment
315
Know the names of the three eras of the Phanerozoic eon
Paleozoic
Mesozoic
Cenozoic
316
Chemical and physical properties of layers in caves- proxy
Ice cores, corals, lake and ocean sediments, stalactites
317
framework silicate
feldspar and quarts
share all 4 oxygen wit hadjacent tetrahedrons
318
Cross-Beds
How do ripples and Dunes Migrate
Wind or water transport grains on upstream side and deposits grains on downstream side
Migrating dune/ripple erodes, the crest in front of it , leaving base as layer behind with crossbedding
Downstream migration of ripples produce crossbedding
Paleocurrent direction
Crossbeds tilt down- current and thus indicate DIRECTION OF FLOW
319
Positive Feedback Examples
Global warming-> permafrost thaws, once frozen organic matter decays by oxidation, release CO2 and CH4 into atmosphere
* Increase warming effect
Global warming-> loss of ice sheets reduces land and albedo, land, oceans, surface air absorvs more energy, increase warming effect
320
WHy have flood basalts been a cause of extinction events
Release SO2- block sun from earth- cool- acid rain
Release CO2- global warming
long lasting eruptions
Deccan Trapps- 1/3; extinction of dinosaurs
Siberian Trapps- Great Dyinh- 95%
321
What are proxy indicators examples
Proxy data
fossils
pollen
chemical and physical propers of layers in caves
stable oxygen isotopes
interglacial
glacial
sediment cores and oceanic microfossils
322
Weather
short term temperatures and precipitation patterns that occur in days and weeks
323
What defines Oxides
bonds with O
324
Paleozoic- organims known for
Crinoids, corals, clams, certain fish, plants, insects, amphibians
325
What does Earth's outer core have to do with alternating magnetic patterns
outer core is liquid iron, constantly moving, convection and rotation (dynamic)
326
Oxides
With oxygen- banded ion formation- iron oxide-red streak
327
What did the opening of the Drake Passage result in?
allowed the water around Antarctica—the Antarctic Circumpolar Current—to flow unrestrictedly west-to-east, which isolated the southern ocean from the warmer waters of the Pacific, Atlantic, and Indian Oceans. The region cooled significantly, and by 35 million years ago, glaciers had started to form on Antarctica.
328
What are the differences between regional, contact, and subduction metamorphism?
Regional
Increasing temperature and Pressure
Heating AND deformation
Foliated
Range of depth
Contact
High temp, low Pressure
Heating NO deformation
Non-foliated
Shallow depth
Subduction
High Pressure low temp
Deformation NO heating
329
Non-Foliated
Texture is granular and equi-dimensional (sugar)
NO alignment/orientation of minerals
NO new minerals form, usually composition of one kind of mineral
Quarts-rich sandstone- Quartzich
Interlocking Quartz cryals
Granual hard rocks
330
lithosphere
curst and upper mantle
outermost layer
strong, rigid, brittle, broken into plates
331
what defines carbonates
CO3
332
Bowen's reaction series
** Illustrates the relationship of silicate minerals and temp ****
Idealized model for crystallization of silicate minerals in a magmatic system
333
Inorganic Sedimentary Rock- Travertine
calcite slowly precipitate from water, leaving thin band/layer (caves and hot spring)
334
Fossils proxy organisms
plants, animals, pollen microorganisms
335
Obliquity
angle Earth’s tilted axis- 41,000 yrs- 21,5-24.5 – 23.5 angle
336
Inorganic Sedimentary- Banded Ions Formations
iron oxide precipitated from ocean water depositing on ocean floor in concentration bands, alternating with chert
337
Major groups of silicates
olivine
pyroxene
amphibole
micas (biomite, muscovite)
feldspars
quartz
338
why are caldera, flood basalts, volcanic dome, stratovolcano more dangerous than scoria or shield
Scoria and Shielf- localized eruptions
Others- explosive eruptions that are far reaching
339
Monocline
step-like folds that rock are upward or downwar, then flat
340
Sedimentary Rock
rocks that are formed from sediment created by weathering (chemical or physical) of pre-existing rocks
341
what is relationship between cooling rate and igneous rock type
extrusive- faster cooling
intrusive- slower cooling
342
Subduction Zone
Convergence
SUBDUCTION and REGIONAL metamorphism
Reverse/Thrust Faulting
FAULT metamorphism and BURIAL metamorphism
CONTACT metamorphism- magma intrusion into continental crust
343
Low viscosity
lava spreaf out- higher temp and FEWER silica chains (mafic)
344
What is the general trend in the Keeling graph?
Increasing
345
Shallow Marine
Continental shelf- Marine
Moderate energy, storms
Important transport process- waves and tidal current s
Main sediment- fine sand and mud
Main rock- mudstone, sandstone, carbonates
Structures- planar bedding, cross beds, storm influence
Main fossils- bioturbation, few marine invertebrates, fish
346
Explosive Pyroclastic Eruption
Explosive eruption
high gas and high viscosity
lava fountaining, pyroclastic flow, eruption channel + ash cloud
347
Fault Meta
Fault where reach duxtile zone- shear rock
Mylongic form- created by dynamic recrystallization through directed shear forces
Larger, stronger mineral crystals may form augments
348
Permineralization
Mineral replacement of original material preserving organisms structures/features
Precipitation from groundwater, petrified wood
349
Earthquake epicenter
Point on Earth’s surface directly above hypocenter
350
Crust
two different- Oceanic and Continental
Oceanic- basalt, 6-7 km thickness
Continental- granite, 35 km thickness
351
Which seismic waves can travel through the Earth and which only travel the upper few kilometers of Earth’s surface/crust.
Surface Wave
352
Physical Layers
Lithosphere
asthenosphere
mesosphere
outer core
inner core
353
Biogenic Chert
Microcyralline quartz made of shells from microorganisms (plankton)
Siliceous ooze in deep ocean, lakes
354
how to become cation or anion
cation- lose electron, become more pos.
anion- gain electron, become more neg.
355
Continental Collision- earthquake
Characterized by broad earthquakes zones that may generate deep, large earthquakes
356
How can we use seismograms to find the epicenter of an earthquake?
Select 3 seismic station records and find P and S waves arrival times to determine the time between
Determine distance of epicenter to each station- radius of circle
Triangular epicenter location
357
Inorganic Sedimentary Rocks - Inorganic Chert
Microcrysyalline quartz precipitated out of silica rich groundwater
Jasper, Flint, Onyx, Agate
358
Lithification
Process which loose sediments become solid rock (cementation and compaction)
359
protolith for quartzite
quartz rich sandstone
360
Continental Rifts- Earthquake
Characterized by small-moderate magnitude earthquakes
361
Lithostratigraphic
Use lithology to determine a similar age of strata
Comp and physical properties of the rocks or sediment
Beds, recognized by visual changes in color, grain size, or comp
Formations, basic division of identifying and correlating sedimentary strata
362
what tectonic setting has no magma formation
continental collision
transform boundary
363
covalent bonding
shares electrons
364
Organic sedimentary rocks
formed from organic material (plants) to procue coal, oil, and natural gas
365
What is the climatic significance of the Younger Dryas event?
One of most well-known examples of aberupt climate change
Weakening of ocean current my melting water- TRIGGERED RAPID COOLING
366
High Viscosity
lava plies out- lower temp and MORE silica chains (felsic)
367
Fossiliferous limestone
abundant visible fossiles (marine invertebrates)
Coral reefs, shallow ocean setting, lakes
368
Intrusive igneous rocks
plutonic
magma solidifies BELOW the surgace
form various features called plutons
369
How does Metamorphism occur
Change in temperature and pressure and depth
Cause existing minerals to be unstable at new conditions
Results in growth of new stable mineral
Change in comp and or texture WITHOUT melting – igneous
370
Can earthquakes be predicted?
NO- but forecast is possible
371
Major defining Characteristic of subduction
Convergent boundary
largest earthquakes and tsunami
deepest earthquakes appear
372
Major defining Characteristic of Continental rift
volcanoes and earthquakes
broad and narrow rifts
373
How do we know the cause of the current change in climate is anthropogenic and not due to increase in solar insolation or volcanic outgassing?
It is not increase in solar insolation because as lower atmosphere is warming, the upper atmosphere is not
Increase in GHG is not due to increase in volcanic activity
Atmospheric carbon isotope signature change
Fossil fuel only source of carbon- consistent with the isotopic fingerprint of carbon present in today’s atmosphere
Fossil fuel has 13C/12C; atmosphere has 14C
13C/12C increased; 14C decreased
374
Normal Faults- stress and plate tectonic
Tensional forces in the crust
Divergent Plate Boundaries
375
Cenozoic- organisms known for
Mammals and grasses
376
Transform Boundaries- earthquake
Characterized by moderate-to-large earthquakes, usually having a maximum ---8
377
Foliation
Refer to any planar metamorphic fabric where minerals are aligned/orientated to have lined up in planes
New minerals form
Common with abundant sheet silicate minerals
Slte, phyllite, schist, gneiss
378
Ice cores dating
Ice core records from Greenland and Antarctica preserve thin layers produced from yearly seasonal cycles
Oldest ice core material- Antarctica- 800,000 years old
379
Rapid Burial- fossil
Less time scavengers and other processes have to destroy/eat specimen
380
What is the Greenhouse Effect- how does it work?
Natural phenomena involving greenhouse gases trapping heat emitted by Earth, warming the atmosphere
381
relationship between grain type, cooling rate, and type of rock
Coarse grained- slower cooling- intrusive
FIne Grained- faster cooling- extrusive
382
Principle of Fossil Succession
Systematic change of unitque fossils through time due to evolution
Fossils or assemblsage of fossils can be used to correlate rocks pf same age across wide geographic distribution
Fossils occur in a definite, determinavble order because evolition is linear
383
What type of fault boundary is most likely to form a tsunami and why?
Subduction- on seafloor
384
Distribution of plants, animals
Long term patterns in temperature and rainfall largely determine climate of region
Changes in their patterns impact distribution of plant and animals community
Pattern determine what crops and livestock can be supported too
385
Earth's Compision layers
- Chemical Layers
Crust, Mantle, Core
386
Stratigraphic
Use stratigraphic relationships between strata that are located in distant geographical areas to determine which are the same age- matching sequence of rock formation
Geologist identify formation using geologic mapping and stratigraphic columns
387
Where are the largest and deepest earthquakes expected to occur and why?
In Subduction Zone- due to subducting slabs- shallow to deep, small to large
388
How is temperature and pressure involved in metamorphism?
Temperature
Heat driven metamorphism occurs at 200 and continues until 700-1100
Pressure
Force exerted over an area, stress= applied force
Strain is product of stress/metamorphic dchanges within minerals
389
Magma compositions of shield volcanoes
low viscous
mafic magma chambers
390
Aeolian
Continental - Wind-blown
Sand dragged along surface or briefly lifted- silt and clay blown away and carried long distances
Main sediment- very well sorted sant and silt
Main rock- sandstone
Main strucute- large cross beds
Main fossils- rare
391
Why does regional metamorphism and fault metamorphism produce foliated, lineated textures?
lots of pressure
392
How do geologists determine a regression or transgress occurred in the rock record of a stratigraphic section?
the Stacks of rocks- newer on top
393
Bedding Planes
Sedimentary material or deposition in horizontal layers forming beds
Beds are bigger than 1 cm thick
Defined by differene in color, sediment size, and/or resistance to erosion
A different bed incidactes change in sediment deposition conditions
394
Secondary Body Wave
Shears material up and down perpendicular to propagation
Second fastest wave
Does NOT travel through Liquid
395
O-C subduction
ocean subducts under continental
on continent- mountain belt with volcano
396
Magma Differentiation
process that changes magma's chemistry towards a more felsic composition over time
fractionation and assimilation
397
Stable oxygen isotopes
Oxygen isotopes record, measuring the ratio of O16 and O18
Oxygen isotope ratio
Colder times= less O16 in ocean water
398
Casts or molds
Original material dissolves leaving cavity
399
mid ocean ridge found is evidence of what
Plate tectonics
400
Why do S-wave travel paths stop at the Mantle-Core boundary causing the S-wave shadow zone?
The Inner Core is liquid, S-Waves can not travel through liquid
