Final Exam Flashcards
(143 cards)
1
Q
Mass movement
A
Gravitationally caused displacement and downslope transport of rock, regolith, and/or snow
Differentiated by material and speed of movement
Kinds:
- Creep
- Slump
- Mud/debris flow
- Rock/debris slide
- Avalanche
- Fall
2
Q
Creep
A
Gradual downslope movement of regolith (unconsolidated material)
- Occurs slowly
- Over years causes trees, fences, foundations, etc. built on a hillside to tilt downslope
3
Q
Slump
A
Mass of regolith detaches from substrate along a spoon-shaped sliding surface and then slips downslope
4
Q
Failure surface
A
Surface upon which a slump slips
5
Q
Head scarp
A
Distinct, curving step at the upslope edge of a slump, where the regolith detached
6
Q
Mud/debris flow
A
During a period of heavy rainfall, water mixes with regolith, creating a slurry that moves downslope
Speed depends on slope angle and amount of water present
7
Q
Rock/debris slide
A
Sudden movement of rock or debris down a nonvertical slope
Leaves landslide scar on slope and debris pile at the base of the slope
8
Q
Avalanche
A
Turbulent cloud of debris mixed with air, rush down steep hill slopes at high speed
Can be snow or debris
9
Q
Rock/debris Fall
A
Mass of rock or debris free-falls from a cliff
10
Q
Desert condition
A
Region is dry due to aridity
- Mountain rain shadows (Okanagan)
- Along cold ocean currents (Atacama, Namib)
- Because of global wind patterns (convergence of cells - Sahara, Australia)
- Continental interiors (Gobi)
11
Q
Desert Varnish
A
Dark coating of iron oxide/manganese oxide and clay that forms on the surface of desert bedrock
- Created by bacteria
12
Q
Dry Wash
A
AKA wadi
Dry stream channel within a desert - forms when flash flood creates stream and is subsequently evaporated
13
Q
Playa
A
Evaporated desert lake; becomes a smooth crust of clay and salts
14
Q
Ventifacts
A
Rocks that have been faceted by the wind
15
Q
Mesa
A
Large, flat topped hill with a surface area of several km
- Strata has been eroded
16
Q
Butte
A
Medium-sized, flat topped hill
- Smaller mesa
17
Q
Lag deposit
A
Wind in deserts carries away fine sediment so that only coarser materials remain
- Lag deposit is these coarser materials
18
Q
Dune
A
Pile of sand that is deposited by the wind
Slip face forms the cross-bedding seen in desert sediments
19
Q
Continental shelf
A
Edge of the continental part of a plate which remains underwater
20
Q
Continental slope
A
Steep slope at the edge of the shelf
- Goes down to ~4.5 km
21
Q
Abyssal Plain
A
Vast, almost horizontal plain at the bottom of the ocean
22
Q
Pelagic sediment
A
Blanket of plankton and clay flakes overlying the basalt of the ocean floor
Gets thicker the further away from a mid-ocean ridge the sediment is, due to increasing age
23
Q
Coastal zones
A
- Shoaling Zone
- Surf Zone
- Intertidal Zone
- Backshore Zone
Progress from being composed more of silt and mud to sand
24
Q
Delta
A
Wedge of sediment formed at a river mouth when the running water of the stream enters standing water
- Current slows, stream loses competence, and sediment settles out
25
Fjord
Deep, glacially carved valley that has been flooded by rising sea level
26
Turbidite
Graded bed of sediment built up at the base of a submarine slope
- Deposited by turbidity currents
27
Submarine canyon
Narrow, deep valley that cuts through the continental shelf/slope
28
Reef
Mound of limestone that was made from coral calcite shells
- Surface of the mound is living coral
Protect the coast from erosion by absorbing wave energy
29
Continental drift
Idea that continents have moved in the past and are still moving slowly across earth's surface
Continents used to match up, evidenced by matching coastlines, matching rock deposits, and matching fossil taxa across continents
30
Lithospheric plate
Consists of continental and/or oceanic crust as well as the uppermost part of the mantle and moves as a coherent unit
- Floats on asthenosphere
- 20 pieces, involved in plate tectonics
31
Divergent plate boundary
New crust is being formed at a mid-ocean ridge or continental rift
Characteristics: mid-ocean ridge (duh), volcanoes, hot spot tracks
32
Mid-ocean Ridge
2km-high submarine mountain belt that forms along a divergent oceanic plate boundary
33
Hot spot track
Chain of volcanoes (most of which are now dead) transported over a hot spot by the movement of a plate
34
Hot spot
Location at the base of the lithosphere that lies at the top of a mantle plume and has high temperatures that can cause rock melting
35
Continental rift
Linear belt along which continental lithosphere stretches and pulls apart
If completed, a rift will split a continent into two smaller parts that are separated by a divergent boundary
36
Convergent plate boundary
A plate boundary where one plate subducts under another (continental-oceanic, oceanic-oceanic)
- If two continental crusts, they will collide
Characterized by: volcanic arcs, trenches
37
Volcanic arc
Curving chain of active volcanoes formed adjacent to a convergent plate boundary
38
Trench
Deep elongate trough bordering a volcanic arc
| - Defines the trace of a convergent plate boundary
39
Transform plate boundary
Boundary at which one plat slips laterally past another
- Connects two other boundaries, usually MORs
- Point in direction of Euler pole
40
Sea-floor bathymetry
Recording the variation in depth of the ocean floor and recording this, pointing out the location of MORs
41
Apparent polar-wander path
Path on the globe along which a magnetic pole appears to have wandered over time
Since they do not match up between continents, it appears that the continents themselves have moved, and NOT the magnetic pole
42
Sea-floor spreading
The gradual widening of an ocean basin as new oceanic crust forms at a mid-ocean ridge axis and then moves away from the axis
43
Euler pole
AKA pole of rotation
Axis around which plates move (?)
- Location can be determined by the directions of transform faults and hot spot tracks
44
Triple junction
A point at which three plate boundaries intersect
45
Felsic
- Increased silica
- More sodium and potassium
- Reduced magnesium and iron
- Reduced density
- Reduced melting temperature
- Reduced melting temperature
- Increased viscosity (sticky)
Occurs in batholiths, subduction zones, composite volcanoes
46
Mafic
- Reduced silica
- More calcium
- Increased magnesium and iron
- Increased density
- Increased melting temperature
- Decreased viscosity (runny)
Occurs in hot spots, mid-ocean ridges, and shield volcanoes
47
Classification of igneous rocks
Mineral content, texture, intrusive vs extrusive
48
Igneous rock texture
Determined by the rate of cooling and depth of formation
- Fine grained = extrusive
- Coarse grained = intrusive
49
Batholith
Vast composite, intrusive igneous rock up to several hundred km long and 100km wide
Formed by the intrusion of numerous plutons in the same region
- Felsic
50
Composite volcano
AKA stratovolcano
Large, cone-shaped subaerial volcano composed of alternating layers of lava and tephra
- Felsic magma
- Tend to be explosive, ashy, and therefore dangerous
51
Shield volcano
Subaerial volcano with a broad, gentle dome
- Formed from either low-viscosity basaltic lava or large pyroclastic sheets
- Mafic magma
- Runny lava flows, less dangerous than composite volcanoes
52
Phase diagram
Shows the temperature/pressure needed for a material to move from liquid to solid state
- With more pressure, higher temperatures are needed for melting
53
Decompression melting
Hot mantle rock rises to shallower depths in the earth; pressure decreases and temperature stays the same
- Occurs at divergent boundaries
54
Heat-transfer melting
Transfer of heating from a hotter magma to a cooler rock causes the rock to melt
- Occurs at hot spots and other hot mantle upwellings
55
Volatile melting
```
Volatile chemicals (water, CO2) mix with hot mantle rock, causing the rock to melt
- Occurs in subduction zones as water moves into a trench
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56
Cinder cone
Subaerial volcano that consists of cone-shaped pile of tephra whose slope approaches the angle of repose for tephra
57
Tephra
Unconsolidated accumulations of debris that was erupted out of a volcano
58
Craton
Long-lived block of durable continental crust commonly found in the stable interior of a continent
59
Caldera
Large, circular depression with steep walls and a fairly flat floor
- Formed after an eruption, as the centre of the volcano collapses into the magma chamber below
60
Metamorphism
Process by which one kind of rock transforms into a different kind of rock
- Rock acquires new minerals and textures without melting it
61
Causes of Metamorphism
Stress
- Pressure, stress, folding
Heat
Chemically active fluids
62
Features of Metamorphic Rock
1. New mineral assemblages
| 2. Changes in texture
63
New mineral assemblages in metamorphic rock
- Solid-state diffusion
- Mineral rearrangement
- Often loss of water/CO2
- Index minerals appear as porphyroblasts
64
Solid-state diffusion
The slow movement of atoms/ions through a solid
65
Index mineral
Minerals that are a good indicator of metamorphic grade
66
Porphyroblasts
Large mineral crystal in a metamorphic rock, grown within a finer-grained groundmass
67
Changes in texture in metamorphic rocks
- Recrystallization
| - Formation of foliations
68
Recrystallization
The process in which ions/atoms in minerals rearrange to form new minerals
69
Foliations
Layerin formed as a consequence of the alignment of mineral grains, or of compositional banding in a metamorphic rock
70
Preferred mineral orientation
Metamorphic texture when platy grains lie parallel to each other, or elongate grains align in the same direction
- E.g. mica in schist
71
Compositional banding
Type of metamorphic foliation that is defined as alternating bands of light and dark minerals
- Found in gneiss
72
Metamorphic grade
Indicates intensity of metamorphism
- Amount or degree of metamorphic change
Relies primarily on temperature
E.g. grades of metamorphic shale:
- slate (silky)
- phyllite (shiny)
- schist (large mica)
- gneiss (compositional bands)
73
Metamorphic facies
A set of metamorphic mineral assemblages indicative of metamorphism under a specific range of pressure-temperature conditions
- More specific than grade
74
Regional metamorphism
AKA dynamothermal metamorphism
Metamorphism of a broad region, usually the result of deep burial during orogeny, also during collision of two continents in convergent plate boundaries
75
Contact metamorphism
AKA thermal metamorphism
Metamorphism caused by heat conducted into country rock from an igneous intrusion
- Relatively localized
76
Hydrothermal metamorphism
Heated seawater dissolves soluble minerals from basalt and gabbro, changing them from dry to hydrous
- Mostly occurs at divergent plate boundaries
77
Shock metamorphism
Occurs at meteor impact sites
| - Sudden heat and pressure
78
Pyrometamorphism
Occurs at lightning strikes and in burning underground coal seams
- High temperature, low pressure
79
Deformation
Three types:
- Translocation
- Rotation
- Strain
80
Translocation
Change in location
81
Rotation
Change in orientation
82
Strain
The change in shape of an object in response to stress
83
Stress vs. strain
Stress is the action, strain is the response
84
Kinds of stress
- Pressure
- Compression
- Tension
- Shear
85
Kinds of strain
- Dilation
- Contraction
- Stretching
- Shear
86
Brittle deformation of rocks
Cracking and fracturing of a material subjected to stress
A. Fractures
B. Faults
87
Fractures
Loss of discontinuity across a surface
- Determined by orientation of stress and pre-existing planes of weakness
a. joints
b. shear fractures
c. veins
88
Joint
Naturally formed crack in a rock
- No shear displacement
- Often in oriented sets
89
Shear fractures
Two planes of fracture, with the two on the edges move in opposite direction form the one in the middle
90
Veins
Fracture filled with minerals
91
Faults
Fracture upon which one body of rock slides past another
Types:
- Normal
- Reverse
- Strike-slip
- Oblique
92
Footwall
The side of a fault that is beneath the angle
| - i.e. the one you would be standing on if you tunneled through the fault
93
Hanging wall
The side of the fault that hangs over the other side
| - i.e. the one that would be over your head if you tunneled through the fault
94
Fault scarp
Small step on the ground where one side of a fault has moved vertically with respect to the other
95
Slickenside
Polished surface of a fault caused by slip on the fault
| - Lineated ones also have grooves that indicate the direction of fault movement
96
Fault breccia
Type of breccia that formed from faulting in a rock
97
Normal fault
Fault in which the hanging wall block moves down the slope of the fault
Accommodate extension and crustal thinning
Form horsts & grabens
98
Reverse fault
Steeply dipping wall in which the hanging wall block slides up the slope
Accommodate tectonic shortening and crustal thickening due to collisional events
- Can be "thin-skinned" (basement rock) or "thick-skinned" (sedimentary cover)
99
Strike-slip fault
A fault in which one block slides horizontally past another (parallel to the strike line)
- No relative vertical motion
- At transform faults
Dextral: faulting pieces move to the right of each other
Sinistral: faulting pieces move to the left of each other
100
Oblique fault
Fault in which sliding occurs diagonally along the fault plane
101
Thrust fault
Shallowly dipping wall in which the hanging block slides up the slope
102
Horst
High block between two grabens
| - Normal fault
103
Graben
Down-dropped crustal block bounded on either side by a normal fault dipping toward the basin
104
Half-graben
Wedge-shaped basin in cross-section that develops as the hanging-wall block above a normal fault slides down and rotates
Between fault surface and rotated surface of block
105
Listric fault
Normal fault in which the fault plane is curved
| - Dip becomes shallower with increasing depth
106
Decollement
AKA Basal detachment
Gliding plane between two rock masses
- Generally, above this is faults
107
Overthrust
Thrust fault with exceptionally low angle and large displacement
- 10s to 100s of kilometeres
108
Klippe
Remnant portion of overthrust material that is no longer connected to the larger body
109
Window
When erosion exposes some of the rock underlying an overthrust
110
Ductile deformation
Deformation of rock with no breaks, just remodelling/changing shape
- Folding
111
Competence
Degree of resistance in a rock to erosion and deformation
| - More competent rocks tend to buckle rather than respond plastically to stress
112
Limb
Side of a fold that shows less curvature than the hinge
113
Hinge line
Portion of a fold where curvature is greatest
114
Inflection point
Point in the limb of a fold where the concavity reverses
115
Axial surface
Imaginary surface that encompasses the hinges of successive layers of a fold
116
Anticline
Fold with an arch-like shape in which the limbs dip away from the hinge
117
Syncline
Through-shaped fold whose limbs dip toward the hinge
118
Classification of Folds
Based on fold orientation and fold shape
- Shape based on interlimb angle
- Orientation based on angle of hinge line/axial plane
119
Secondary enrichment
New ore deposit forms from metals that were dissolved and carried away from preexisting ore minerals
120
Residual deposits
Soils in which the residuum left after leaching by rainwater is so concentrated in metals that the soil itself becomes an ore deposit
121
Natural oil/gas deposits
Source is dead algae and plankton
- Generated in black shale
- Hotter for gas
Hydrocarbon moves into reservoir rock and gets trapped
- Trapped by intrusions, faults, unconformities
122
Tar sands
Sandstone reservoir rock in which less viscous oil and gas molecules have either escaped or been eaten by microbes, so that only tar remains
123
Oil shales
Shale containing kerogen (which becomes oil at higher temperatures)
124
Coal
Formed from swamps in which oxygen-poor waters allow thick piles of woody debris to accumulate and become coal upon deep burial (4-10km)
Swamp --> peat --> lignite --> anthracite
125
Placer deposit
Concentration of metal/gemstone grains in stream sediment that develop when rock containing native metals erode and create a mixture of sand grains and metal/gemstone fragments
- Moving water of stream carries away lighter fragments
126
Igneous crystallization
Within a magma chamber, there is density segregation of materials - heavy ores settle down to the bottom and produce rich deposits
127
Pegmatite
Igneous rock that is coarse-grained and can contain large crystals (tens of centimetres across)
- Occur in dike-shaped intrusions
128
Kimberlite
Unusual magma that is deep-rooted, shoots through the lithosphere and forms a cone
Brings high-quality diamonds from deep within the earth to the surface quick enough that they are not destroyed
129
Black smokers
Sulfide-rich hot water vents at mid-ocean ridges
| - Dissolved components immediately precipitate out when they mix with cold seawater, and settle, forming a rich deposit
130
Hydrothermal deposit
Accumulation of ore minerals precipitated from hot-water solutions moving through magma/intrusions/veins
131
Mine cycle
1. Exploration
2. Approval (for mining)
3. Operation
4. Reclamation
132
Strip mining
Scraping off of all soil and sedimentary rock above a coal seam in order to gain access to it
133
Open pit mining
Extracts rock from the earth by removal from an open hole in the ground
134
Underground mining
Mining that occurs in a tunnel built under the ground
135
Stakeholders in mining operations
- Company
- Communities
- Government
- Aboriginal peoples
136
Benefits to Mining in Canada
In 2009, $32 billion was added to the GDP from mining
- 306,000 workers
- $5.5 billion in taxes and royalties
Over 3,200 companies provide input to the industry
137
Problems with mining in Canada
Environmental
- pollution
- damage to ecosystems and wildlife
Social
- alienation of aboriginal rights
138
Prosperity Mine
125km SW of Williams Lake in BC
Over 75,000 tonnes mined per year for 20 years
1.5km open pit with onsite mill, tailings, waste rock areas
125km power transmission corridor
3km gravel road
139
Geologic Units of Ontario
From bottom:
1. Archean/Proterozoic
2. Paleozoic
3. Glacial
(4. Anthropogenic features)
Major unconformities exist between each of these
140
Archean Ontario
Superior province thought to have originated from collisions of island arcs
- Granite-greenstone with sediments (possible accretionary prisms) in between
- ~100km wide E-W trending belts
Kapuskasing structural zone shows cross-section through the lower crust
141
Proterozoic Ontario
Southern Province (2.5-2.2 Ga)
- 12 km thick sedimentary rocks
- Huronian supergroup experiences rifting and climate fluctuation
- Elliot Lake group has conglomerates with unraninite and gold (placer??)
- Gowconda Formation shows evidence of glaciation
Mountain belts weld Archean provinces together
- Formation of supercontinent Nena
- Folds Huronian supergroup
Sudbury Impact (1.8 Ga)
- 10km meteor, 250km crater
- Melted crust, which then froze and became very metal-rich
- Originally thought to be volcanic structure
- Now mined
Grenville orogeny (1.3 Ga)
- Formed supercontinent Rodinia
- High-grade metamorphism, ductile deformation
Midcontinental Rift (1.1 Ga)
- 2,000km long and 20km thick
- Flood basalts with copper deposits
- Possible failed triple junction
Grenville mountains completely eroded by 800 Ma
142
Paleozoic Ontario
The "Great Unconformity"
- Around 500 years missing
Ordovician
- Clastic Sediments
- First pulse of Appalachian orogeny
Silurian
- Sea level rises
- Shallow sea with reef carbonates
Devonian
- Second pulse of Appalachian orogeny, bulges up Algonquin arch
- Evaporites in shallow, warm inland seas
- Ontario near equator
143
Neogene Ontario
Ice Ages
- Four major ice sheets with interglacial periods in between
- Last interglacial exposed in Don Valley Brickworks
Oak Ridges Moraine
- Formed from two ice sheet lobes merging
- Now an essential aquifer
Formation of Niagara gorge
- Change in drainage pattern
