Final Exam Flashcards
(220 cards)
1
Q
What is the definition of geography?
A
The science that studies the relationships and interdependence of geographic areas, natural systems, and cultural activities
2
Q
What is spatial?
A
Term that refers to the nature and character of physical space, its measurement, and the distribution of things within it
3
Q
Why does geography require a spatial perspective?
A
A spatial perspective is a way of thinking about how and why physical features/processes are positioned in geographic space
4
Q
What are the five themes of geographic science?
A
Location
Place
Region
Movement
Human-earth relationships
5
Q
What is physical geography?
A
The science concerned with the spatial aspects and interactions of the physical elements and process systems that make up the environment
6
Q
Define location
A
Is specific and absolute, allows you to discuss places in absolute terms
Ex. coordinates
7
Q
Define place
A
Is subjective, every place has a distinct group of physical features, and changes over time
Ex. a town or city
8
Q
Define region
A
A group of places that have physical features or human characteristics (or both) in common
Ex. tropical rainforest region
9
Q
Define movement
A
Animals, plants and other physical features of earth move from one place to another, can be affected by natural barriers
10
Q
Define human-earth relationships
A
Humans depend on, adapt to, and modify the world around them: humans and the environment are shaping each other
11
Q
Describe the process of science (the scientific method)
A
Six steps:
Observation
Hypothesis/prediction
Experiment, measure, test hypothesis
Analyze results
Peer review
Iteration (conclusion further tested by other researchers)
12
Q
What is a system?
A
Any ordered/interrelated set of things and their attributes
Linked by flows of energy and matter
Distinct from the surrounding environment outside the system
13
Q
What is an open system?
A
Not self-contained
Inputs of energy and matter flow into the system, outputs of energy and matter flow out of the system
Ex. rivers, forests, hurricanes
14
Q
What is a closed system?
A
Systems that are shut off from the surrounding environment
Are very rare in nature
Ex. earth is an open system in terms of energy, but a closed system in terms of physical matter and resources
15
Q
What are the earth’s four spheres?
A
Atmosphere
Hydrosphere
Lithosphere
Biosphere
16
Q
What is a negative feedback loop?
A
Feedback information maintains self regulation, stable condition
Ex. vegetation (temps rise -> enhanced vegetation growth -> enhanced CO2 uptake –> temps rise and maintain stability)
17
Q
What is a positive feedback loop?
A
Feedback information increases response in the system, a runaway condition (snowballing)
Ex. albedo (temps rising -> sea ice melts, exposes darker ocean surface -> albedo is altered, ocean reflects less sunlight -> ocean absorbs more heat -> temps rising)
18
Q
What is geodesy and what is a geoid?
A
Geodesy = science that determines Earth’s shape and size
Geoid = the unique, irregular shape of the Earth’s surface
19
Q
What purpose does a reference ellipsoid serve?
A
It is a mathematically defined best-fit surface that approximates the physical shape of the earth. It is used as a reference for coordinated grid systems.
20
Q
Define latitude
A
An angular distance north or south of the equator, measured from the centre of the earth
21
Q
Define longitude
A
An angular distance east or west of a point on the earth’s surface, measured from the centre of the earth
22
Q
Define parallel
A
A line connecting all points along the same latitudinal angle
23
Q
Define meridian
A
A line connecting all points along the same longitude
24
Q
Define a great circle
A
Any circle drawn on a globe with its centre coinciding with the centre of the globe
25
Where is the prime meridian?
The greenwich meridian (line from the north pole to south pole, through Greenwich, England)
26
What is a map?
A generalized view of an area, usually some portion of Earth's surface, as seen from above at a greatly reduced size
27
Define map scale
A ratio of the image on a map to the real world
28
What are the three types of map scales?
Representative fraction (1:25,000)
Written scale (1cm=250m)
Graphic scale (a bar scale)
29
What is a large-scale map?
1:50,000 or less, show a smaller area in more detail
30
What is an intermediate-scale map?
Intermediate-scale maps are 1:50,000-1:250,000
31
What is a small-scale map?
Small-scale maps: 1:250,000 and higher, show a greater area in less detail
32
Define map projection
Reduction of a spherical globe (earth) onto a flat surface (paper) in an orderly and systematic realignment
33
What are the four general classes of map projection?
Cylindrical (like mercator projection)
Planar (shows full hemisphere on one projection)
Conic (less distortion at the mid-latitudes)
Oval (compromise, keeps distortion to minimum)
34
What is an endogenic system?
They encompass internal processes that produce flows of heat and material from deep below earth's crust
Main energy source: radioactive decay
35
What is an exogenic system?
Involved external processes that set into motion air, water, and ice
Powered by solar energy
Ex. rivers, landforms, weathering, erosion, oceans, glaciers
36
What are short-timescale events?
Volcanic eruptions, meteor impacts, landslides
37
What are long-timescale events?
Mountain building, canyon incision, formation and breakup of supercontinents (plate tectonics), infilling of sedimentary basins
38
From largest to smallest, what are the intervals of the geologic time scale?
Eon > Era > Period > Epoch
39
How much time does the geologic time scale break down?
The age of the earth - the last 4.6 billion years
40
How are boundaries of the geologic time scale determined?
Boundaries are based on major events in earth's history
41
How old is the universe?
13.7 billion years old
42
How are the ages of rocks (and thus the earth) determined?
Through absolute dating that provides the numerical ages of materials
43
How old are the oldest rocks on earth?
About 4 billion years old
44
Where on earth are the oldest rocks found?
In Greenland, the Canadian Shield, and western Australia
45
How did the earth form?
It condensed and congealed from a cloud of dust, gas, and icy comets about 4.6 billion years ago
As temperature decreased, the earth solidified and gravity sorted materials by density, forming layers
46
Describe continental crust
Thicker
Mostly granite from volcanic processes
Lower density
47
Describe oceanic crust
Thinner
Mostly basalt extruded from cracks in earth's crust
Higher density
48
What is isostasy?
The state of gravitational equilibrium between the lithosphere and asthenosphere
49
What causes isostatic rebound?
Recovery uplift of the crust
Ex. after periods of glaciation
50
What causes isostatic depression?
Crust sinking into the asthenosphere
Ex. by weight of glacial ice during continental glaciation
51
Define mineral
Nonliving, naturally occurring compound with a specific chemical formula and a crystalline structure
52
Define rock
An assemblage of minerals bound together
Or a mass of a single material
53
What are the two most common mineral groups in the earth's crust?
1. Silicates
2. Carbonates
54
Define and describe the formation of igneous rocks
Igneous rocks form volcanically and solidify (crystallize) from a molten state
Small crystals -> rapid cooling -> extrusive
Large crystals -> slow cooling -> intrusive
55
How do clastic sedimentary rocks form?
Through compaction, cementation, and hardening of sediments into sedimentary rock
(process of lithification)
56
How do chemical sedimentary rocks form?
From direct precipitation from a water solution
57
How do biochemical sedimentary rocks form?
From accumulation of shell material, and biological oozes
58
What are the two main types of metamorphism and their rock crystal sizes?
Regional metamorphism: results in smaller crystals, layered and banded rocks
Contact metamorphism: results in larger crystals
59
What powers the rock cycle?
Internal convection currents
Solar power
60
Define continental drift
All landmasses migrate and once (approx 225 million years ago) formed one supercontinent, Pangaea
61
What are the four lines of evidence for the theory of plate tectonics?
1. The obvious fit of the continents
2. The same rocks are found on previously adjoining continents
3. Fossils of the same organisms are found on now widely separated southern continents
4. Paleoclimatology (past climate clues) like glacial striations
62
What is seafloor spreading?
Areas of oceanic crust where magma upwelling causes it to split
Mid-ocean ridges are seafloor spreading centres
63
How does paleomagnetism help explain seafloor spreading?
Paleomagnetism is the magnetic field of the earth recorded in rocks
Magnetic surveys across Mid Ocean Ridges show patterns of positive and negative anomalies as mirror images on either side
64
How do earthquakes, volcanoes, and hot spots support the theory of plate tectonics?
Most (almost all) of this activity occurs along tectonic plate boundaries
65
What are the three main types of plate boundaries?
Divergent plate boundaries
Convergent plate boundaries,
Transform boundaries
66
At each plate boundary, is crustal Lithosphere material generated or destroyed?
Divergent plate boundaries: lithosphere is produced by upwelling magma
Convergent plate boundaries: lithosphere is destroyed by collision
Transform boundaries: lithosphere is neither produced nor destroyed
67
What is relief?
Elevation differences in a local landscape; an expression of local height differences between landforms
68
Define topography
Undulations and other variations in the shape of Earth's surface (including its relief) like mountains, basins, plains, high tablelands, hills and low tablelands
69
Describe the three orders of relief
First order of relief: coarsest level, zoomed out, ex. satellite view
Second order of relief: intermediate level, ex. mountain ranges, plains, lowlands, mid-ocean ridges
Third order of relief: most detailed level, ex. individual mountains, cliffs
70
How is new crust formed?
From tectonic activity (powered by endogenic or internal energy processes) combined with weathering and erosion (powered by the sun through motion of air, water and ice)
71
Where is the oldest and youngest crust in Canada?
Oldest - Northern Canada
Youngest - areas of volcanic activity
72
What is terrane accretion?
Terrane is a migrating piece of earth's crust
Transported a distance by processes of plate tectonics → these “exotic” terranes are distinct from the continents that accept them in terms of history, composition and structure
BC formed from accreted terranes
73
What is stress and its three types?
Stress: rocks are subjected to stress due to tectonic forces, gravity, and the pressure from overlying rocks
Tension stress = stretching
Compression stress = thickening/shortening
Shear stress = twisting
74
What is strain?
Strain is how rocks respond to stress, results in rocks folding (bending) or faulting (breaking)
75
What is orogenesis?
Orogenesis means mountain building: the process of mountain building occurs when large-scale compression leads to deformation and uplift of the crust; literally, the birth of mountains
76
Define orogeny
A mountain-building episode that occurs over millions of years
77
Describe an earthquake
The sharp release of energy that occurs at the moment of movement along a fault, producing seismic waves
78
What is seismology and its components?
Seismology: the study of seismic (earthquake) waves
Seismometer: instrument that records earthquakes
Seismogram: the record itself of the waves
79
What are the main types of seismic waves?
Body waves travel in earth's interior; P waves (fast, not damaging) and S waves (slow, not damaging)
Surface waves travel on earth surface; L waves are slowest waves and cause the most damage
80
What is an earthquake epicenter?
The projection of the focus on the surface of the Earth
Determined by triangulating locations of seismic waves from 3+ seismometers
81
Where does volcanism occur?
At plate boundaries, subduction zones, and hot spots
82
Describe an effusive volcanic eruption
Lavas are low viscosity, gases can easily escape, flow rather than explode
Less destructive, no ash clouds, no explosions
Occurs at divergent boundaries, rift zones, hot spots
Results in shield volcano
83
Describe an explosive volcanic eruption
Lavas are high viscosity, gases cannot escape so they erupt explosively
More destructive, ash clouds, pyroclastic flows
Occurs at convergent boundaries
Results in composite or stratovolcanoes
84
Define denudation and the main processes involved
Any process that is removing rock, wears away or rearranged landforms
Processes include weathering, mass movement, erosion, transportation, and deposition
85
What is weathering?
The process that breaks down rock at Earth's surface (and slightly below)
86
What is differential weathering?
Different rates of weathering as a result of differences in resistances of rocks (or differences in intensity of weathering)
Results in an uneven surface where more resistant material protrudes beyond softer or less resistant material
87
What factors influence weathering processes?
Rock composition
Rock structure
Surface and sub-surface water
Climatic conditions
Slope orientation
Vegetation
Time
88
Describe frost action weathering
Water infiltrates into cracks, expands as it freezes, force from expansion overcomes tensional strength of rock, cracks widen, splitting rocks into smaller blocks
89
Describe salt-crystal growth weathering
In warm arid (dry) climates, evaporation removes moisture from rock surface
Previously dissolved salt minerals are left behind
Salt crystals accumulate and grow
Growth exerts force on rocks strong enough to separate grains, breaking the rocks into smaller pieces
90
Describe pressure-release jointing
The process whereby rock peels or slips off in sheets instead of breaking up into grains
Creates arch- and dome-shaped features on landscape
Formed as pressure is released from the removal of overlying rock
91
Describe desiccation cracking
Clay-rich rocks and sediments expand when wet and contract when dry
92
Describe hydration chemical weathering
Water is added to the structure of a mineral, increasing its volume, creating stress and disintegration of rocks
Mineral is changing, not being broken down
93
Describe hydrolysis
Water combines with minerals to form new, larger, softer, weaker compounds
Decomposition of a chemical compound by reaction with water. Differs from hydration in that mineral is being chemically broken down
94
Describe oxidation
Rusting: metallic elements (Fe, Al) combine with oxygen to form oxides → larger, softer, more erodible compounds are formed
95
Describe carbonation
Water vapour readily dissolves CO2, (present in atmosphere), producing acidic precipitation
96
What is dissolution?
When a mineral dissolves into solution
97
What is karst topography?
A limestone region with a specific landscape of pitted, bumpy surface topography
Poor drainage, well-developed solution channels underground due to chemical weathering
98
What is required for karst topography to form?
Limestone must contain 80% or more calcite (calcium carbonate)
Limestone must be jointed to provide access to subsurface
Aerated zone must exist between ground surface and water table
Vegetation cover must exist, supplies organic acids to enhance dissolution process
99
What are some landforms associated with karst topography?
Sinkholes, karst valleys, disappearing streams, caves, caverns, stalactites and stalagmites
100
What is a mass movement?
The downslope movement of a body of material made up of soil, sediment, or rock propelled by the force of gravity
Can occur on land or underwater
101
What are the five main factors that cause mass movements?
Slope angle (steepness etc)
Forces (gravity, resisting force)
Water (fluids act as lubricants)
Earthquakes (shake debris loose/fracture rock)
Volcanic eruptions (affect slope)
102
What is the angle of repose on a slope?
The steepest angle at which a sloping surface is stable
Represents a balance between gravity (driving force) and resisting force
Depends on the size and texture of grains/soils
Normally between 33 and 40 degrees
103
What are the 4 main classes of mass wasting?
1. Fall (material falls through air and hits a surface)
2. Slide (rapid movement of a cohesive mass that is not saturated with moisture)
3. Flow (when material is moving and is saturated)
4. Creep (persistent, gradual mass movement of surface soil in which individual soil particles are lifted and disturbed over time)
104
What is the term for human-induced mass movement and what are four examples?
Scarification
Examples: Highway roadcut, surface mining, housing development, forest clear-cut
105
Where does water on Earth originate from?
Icy comets, hydrogen- and oxygen-laden debris from extraterrestrial collisions
106
What is the distribution and location of water on earth?
97% ocean water
3% freshwater (mostly surface water (ice/glaciers, lakes, rivers) rest groundwater)
107
What are the two pathways for precipitation that reaches Earth's surface as rain?
1. Flows over land
2. Soaks into soil
108
What is infiltration?
Process by which water soaks into subsurface (penetration of the soil surface, requires surface material to be permeable (allow water to flow through pores or cracks)
109
What is overland flow?
“surface runoff” water that flows across the land surface toward stream channels
110
What are the three main surface water resources?
1. Snow and Ice
2. Rivers and lakes
3. Wetlands
111
What is the definition of groundwater?
Water beneath the surface that is beyond the soil-root zone; a major source of potable water
112
Define zone of aeration
Area where soil and rock are not saturated (pore spaces contain air)
113
What is the zone of saturation and the water table?
Zone of saturation: area where pore spaces are completely filled with water
Water table: upper limit of zone of saturation
114
What is an aquifer and a drawdown?
Aquifer – a subsurface layer of permeable rock or sediment through which groundwater can flow
Drawdown – lowering of the water table due to excessive pumping of water from aquifer
115
Define a stream
Any surface water flow confined to a channel regardless of size
116
Define a river
The trunk or main stream of the network of tributaries forming a river system
117
What is a drainage basin? How do they form?
“watershed” – the portion of a landscape that holds river systems and the land that feeds them
Form when water moves downslope as sheetflow, which concentrates in rills, develops into gullies, which feed into streams
118
What are the 7 most common drainage patterns?
Dendritic
Trellis
Radial
Parallel
Rectangular
Annular
Deranged
119
Where would you expect to find a low drainage density vs a high drainage density?
A typical desert has a very low drainage density while a humid climate is associated with a high drainage density
120
What is stream gradient and base level?
Gradient of a stream = drop in elevation per unit distance
Base level = level below which a stream cannot erode its valley
121
What is stream discharge and how is it calculated?
Discharge (“runoff”) = the streamflow volume passing a point (e.g., outlet of a watershed) in a given unit of time
Calculated as Q = W x D x V
W is the width of the channel
D is the depth of the channel
V is the river velocity
122
How does discharge change with distance downstream?
Most streamflows increase discharge downstream because the area being drained increases
Urbanization can increase peak flow and shorten lag time between storm peak and stream discharge peak
123
How does stream channel flow work?
Unsystematic, irregular, different directions, different speeds
Affected by friction, width & depth of channel, roughness of channel floor
124
What is hydraulic action?
A type of erosive work performed by flowing water alone, a squeeze-and-release action that loosens and lifts rocks
125
What processes cause fluvial incision?
Incision = streams erode downward
Caused by hydraulic action (water power), abrasion (grinding by rocks), corrosion (chemical action)
126
Define a meandering stream and its erosional fluvial landforms
Occurs where channel slope is gradual (low gradient)
Streams develop a more sinuous (snakelike) form, weaving back and forth across the landscape in a pattern
Erosional fluvial landforms include point bars, cut banks, oxbow lakes
127
How is stream sediment load transported?
Most occurs in high flow locations and is carried by water through saltation (bouncing), traction (rolling/dragging), suspension (carrying)
128
What are common stream channel patterns?
Multiple-thread channels: braided and anabranching
Single-thread channels: straight and meandering
129
What is a graded stream?
Stream in which a state of equilibrium between gradient and sediment load has been reached
Channel slope has adjusted so that stream velocity is just enough to transport the sediment load
130
What are the main depositional landforms associated with fluvial environments?
Floodplains, terraces, alluvial fans, river deltas
131
How is a glacier defined?
A large mass of ice resting on land or floating as an ice shelf in the sea adjacent to land
132
What is the difference between continental and alpine glaciers?
Continental: larger scale and flow not affected (or minimally affected) by topography
Alpine: smaller sale and flow controlled by topography
133
What are the four types of alpine glaciers?
1. Cirque glacier
2. Valley glacier
3. Piedmont glacier (at base of mountain range)
4. Tidewater glacier (ends in body of water influenced by tides)
134
Define: ice sheet, ice cap, ice field
Ice sheet: a mass of glacier ice that covers an area of more than 50,000 km2 (continental scale). Covers both high and low elevation areas.
Ice cap: roughly circular and covers an area of less than 50,000 km2 in mountainous regions
Underlying landscape completely covered
Ice field: an elongated pattern (ice field’s area usually is less than that of an ice cap), covers an area of less than 50,000 km2 . Found in mountainous regions.
Underlying landscape completely covered
135
How does snow become glacial ice?
Snow falls and doesn't melt, it then buries and compresses previous layers, granular ice turns to firn, then forms glacial ice
136
What is firn?
Granular, partly compacted snow that is intermediate between snow and ice
137
What are positive and negative mass glacier mass balance?
Positive net mass balance – when a glacier is gaining more mass than it is losing
Negative net mass balance – when a glacier is losing more mass than it is gaining
138
What are the accumulation zone, ablation zone, and equilibrium line on a glacier?
Accumulation zone: where the amount of new ice formed is more than what is loses
Ablation zone: where the amount of new ice formed is LESS than what it loses (retreat)
Equilibrium line: boundary between accumulation and ablation zone
139
What are the two types of glacial motion?
1. Internal deformation - flowing of ice in response to the weight and pressure of overlying snow and the degree of the underlying slope
2. Basal slip - sliding of the bottom of the glacier due to presence of lubricating water beneath the ice
140
What are the characteristics of an advancing vs. retreating glacier?
Advancing glacier:
Ablation < accumulation
Ice moves forward (downhill) and the ice margin moves forward (downhill)
Ice surface may increase in elevation (ice thickens)
Retreating glacier:
Ablation > accumulation
Ice moves forward (downhill) and the ice margin retreats (uphill)
Ice surface may decrease in elevation (ice thins)
141
What is a moulin?
A vertical shaft in a glacier formed by surface water percolating through a crack in the ice
142
What data exists on mass balance changes for glaciers in Canada?
All glaciers exhibit a negative trend in mass balance in the period of measurement from the early 1960s to the present
143
What are the two main process by which glaciers erode a landscape through physical weathering?
1. Plucking - the passing glacial mechanically picks up rock material and carries it away
2. Abrasion - rock pieces frozen to the basal layers of the glacier enable the ice mass to scour the landscape like sandpaper as it moves
144
Where does a glacier carry debris in transportation?
Debris eroded by plucking and abrasion is transported englacially (internally), embedded within the glacier itself
Some debris falls onto top of glacier and is transported supraglacially (on the surface)
Debris frozen to the base of the glacier is transported subglacially (at the base)
145
What is glacial drift?
The general term for all sediments of glacial origin, including:
Till (sediment deposited directly by glacial ice, usually very poorly sorted, unstratified debris)
Glacial erratics (boulders with different rock types from local bedrock found in till or on the land surface)
Glacial outwash (“stratified drift”, layered sediments laid down by glacial meltwater)
146
What are the 3 main types of landforms produced by glacial erosion?
1. Striations and grooves
2. Roche mountonee
3. Glacial valleys
147
What depositional landforms are formed by alpine glaciation and continental glaciation?
Alpine: moraines (lateral, medial, and terminal)
Continental: till plains, outwash plains, drumlins, eskers, kettles
148
Define periglacial
Meaning "on the perimeter of glaciation", places where geomorphic processes related to freezing water
149
What is permafrost?
Perennially frozen ground - soil, sediment or rock that remains below 0 degrees for at least 2 years
Not covered by glaciers
150
What is ground ice?
Water present within permafrost in the form of ice
151
What are the two zones of permafrost distribution?
Continuous zone
– Region of severest cold (mean annual temp of -7°C)
– Affects all surfaces except beneath deep lakes or rivers
– Depth of permafrost averages 400 m
Discontinuous zone
– Region where mean annual temperatures are at least -1°C
– Unconnected patches of permafrost (some ground is not frozen)
– Mostly occurs on north-facing slopes (in N hem) or areas not insulated by snow
152
What is talik?
Unfrozen ground that may occur above, below,
or within a body of discontinuous permafrost
Or beneath a water body in the continuous zone
153
What is an active layer?
The zone of seasonally frozen ground
that exists between subsurface permafrost layer and the ground surface
Experiences consistent daily or seasonal freeze-thaw cycles
154
What are factors that affect the presence of frozen ground?
– Seasons
– Latitude
– Altitude
– Local landscape
– Slope
– Climate
155
What are the 6 causes of frost-action processes?
1. Frost heaving (vertical movement of ground due to ice)
2. Frost thrusting (horizontal movement of ground due to ice)
3. Block fields (repeated frost-wedging)
4. Ice Wedges (when water enters a crack and forces apart rock)
5. Patterned Ground (expansion and contraction due to frost makes shapes)
6. Pingos (large areas of frozen ground develop heaved-up, circular, ice-cored mounds)
156
What is a thermokarst landscape?
Landscape that results from the thawing of permafrost
Hummocky topography (small depressions, standing water, and thaw lakes)
157
What is solifluction or gelifluction?
When the active layer is saturated with soil moisture during the thaw cycle (summer) and flows from higher to lower elevation
158
When was the Quaternary Period?
The last 2.6 million years
Time of major climate fluctuation
159
When was the Pleistocene Epoch?
2.6 million - 10 thousand years ago
Within the Quaternary Period of the Cenozoic
160
What is an ice age?
Any extended period of cold, in some cases lasting several million years
– Includes glacials and interglacials
161
Define glacial and interglacial
Glacial – a period of time characterized by glacial advance
Interglacial – a brief warm spell occurring
between glacial periods, characterized by glacial retreat
162
What ice sheets covered Canada during the last glacial maximum and where?
Laurentide ice sheet covered eastern Canada
Cordilleran ice sheet covered western Canada
163
When was British Columbia completely deglaciated?
About 9000 years ago
164
How was BC's landscape affected by the last ice age?
British Columbia’s landscape is a result of glacial erosion and deposition
* Steep mountainsides and unconsolidated sediment
* Landslide hazards
In the Okanagan: valleys deepened and widened
165
What is soil?
A complex plant-supporting system that consists of:
– Disintegrated rock
– Organic matter
– Water
– Gases
– Nutrients
– Microorganisms
166
What is soil science? What is pedology?
Soil science – the interdisciplinary study of soil
as a natural resource on Earth’s surface
Pedology studies the origin, classification,
distribution, and description of soil
167
How is soil produced?
1. Mechanical and chemical weathering of parent material (the surface material (rock or sediment) in which soil forms)
2. Accumulation and decay of organic material
168
Describe the principal natural soil-formation factors
Climate
Organisms (biological processes)
Topography (slope)
Parent material
Time
169
What is a soil profile?
A vertical section of soil that extends from
the surface to the point where regolith or bedrock is encountered
Horizons: distinct horizontal layers within soil
170
What are the five main soil horizons?
O horizon: organic material on top
A horizon: organic and mineral material near top
B horizon: formed by accumulation of material removed from A horizon
C horizon: transition zone below B horizon
R horizon: unaltered parent material
171
What are the common properties used to classify soils?
Color, texture, structure, chemistry, pH (acidity and alkalinity)
172
What is loam?
A balanced mixture of sand, silt and clay
173
How does soil colour suggest composition and chemical makeup?
Red soils indicate presence of iron oxides (e.g. in PEI)
Black soils indicate high humus content (e.g. in prairies)
The Munsell color chart is a standardized way to determine soil color
174
What is a soil textural triangle?
Used to classify the texture class of a soil, the sides of the triangle are scaled for the percentages of sand, silt, and clay
Clay percentages are read from left to right across the triangle (dashed lines)
Silt is read from the upper right to lower left (light, dotted lines)
175
What are soil colloids?
Tiny particles of clay or humus contain a
negative electric charge, which attract positive ions
Soils with high amounts of soil colloids are said to have high cation-exchange capacity – meaning they are fertile!
176
How do human impacts affect soils?
Human intervention has a major impact on soils.
* Soils do not reproduce, nor can they be re-created.
* 35% of farmlands are losing soil faster than it can form from bedrock weathering
177
What is desertification?
Land degradation that occurs in dry regions (the expansion of deserts)
– Loss of topsoil in arid or semi-arid regions is enhanced by agricultural activity
– Common in areas already affected by poverty
178
Why are oceans and coastlines important when considering climate change?
Oceans act as a buffer for changes in other Earth systems
Recent climate change may now be overwhelming oceanic systems (sea ice melting, sea-level rise, etc)
About 40% of Earth's population lives within 100km of the coast
179
Describe water as a universal solvent
Water dissolves more substances than any other liquid
180
What is salinity?
The salt content of water
181
What is brine? How does it differ from brackish?
Brine – Salinity is greater than 35 parts per thousand (occurs in subtropics where evaporation is high)
Brackish water - Salinity is LESS than 35 parts per thousand (occurs near landmasses with freshwater inputs)
182
What are the three zones of the ocean's physical structure?
1. Mixing zone (2%) at top
2. Thermocline zone (18%)
3. Deep cold zone (80%)
183
Describe the chemical composition of seawater
Seven elements account for more than 99% of the dissolved solids: chlorine, sodium, magnesium, sulfur, calcium, potassium, and bromine
184
Why is ocean acidification a problem?
Acidification can create conditions that eat away at the minerals used by oysters, clams, lobsters, shrimp, coral reefs, and other marine life to build their shells and skeletons
185
How does ocean acidification occur?
Ocean absorbs CO2 from the atmosphere, forms carbonic acid in the seawater, and lowers the ocean pH value (makes it more acidic)
186
In which oceanic zone do coastlines occur?
In the littoral zone
187
What are the three main causes for sea level change?
Climatic - thermal expansion of sea water
Tectonic - oceanic crust rising bc of mid ocean ridges
Eustatic - changes of volume of water in oceans, related to isostasy
188
How much lower was sea level during the last ice age?
About 130m lower than it is today
189
What are tides?
Complex, twice-daily oscillations in sea level,
ranging worldwide from barely noticeable to a rise and fall of several meters
190
What are the four main types of tides?
Flood tides - incoming rising tide that occurs twice a day
Ebb tides - a falling tide that occurs twice a day
Spring tides - occurs when the Sun and Moon are in alignment on the same side of the earth (full moon and new moon)
Neap tides - occur when the Moon and Sun are not in alignment with Earth (during quarter moons)
191
Why does the Bay of Fundy have the highest tides?
The shape of the bay, and an unusual combination of resonance (or seiche) that causes rocking like a bathtub
192
What is tidal bulge?
Stretching in the Earth’s oceans as a result
of the gravitational pull of the Sun and/or Moon
193
What is tidal range?
The difference in elevation (m) between
consecutive high and low tides.
194
What is coastal straightening and how does it occur?
The long-term effect of wave refraction is straightening of the coast
195
What are waves?
Undulations of water generated by friction
between wind and the ocean surface
– Vary greatly in scale
– Waves travel in groups called wave trains
196
What are swells and breakers?
Swells – smooth, round-shaped, long-crested, uniformly symmetrical waves that have traveled outside the area of their origin
– Can range from small ripples to very large waves
* Breaker – the point where a wave’s height exceeds its vertical stability and the wave breaks as it approaches the shore
197
What is a longshore current?
A current that forms parallel to a
beach as waves arrive at an angle to the shore
– Generated in the surf zone by wave action
– Depends on wind direction and resultant wave direction
198
What is littoral drift?
Transportation of large amounts of sand
and sediment along the shore by the longshore current
199
Define a tsunami
(Japanese for “harbour wave”) – a series of waves generated by a large under-sea disturbance (earthquakes, submarine landslides, eruptions)
200
Describe erosional coastal processes and landforms and where they occur
Rugged, high relief, and tectonically active
Such as coastlines of the Pacific Ocean along North and South America
201
Describe depositional coastal processes and landforms and where they occur
Depositional coasts are along land of gentle relief, such as the Atlantic and Gulf coastal plains.
Relatively passive, and tectonically inactive
202
What are the 5 erosional coastal landforms?
1. Sea cliffs (formed by the undercutting action of the sea)
2. Wave-cut platforms (form when wave action cuts a bench in the tidal zone)
3. Sea caves (form on headlands by physical erosion)
4. Sea arches (form when further erosion of a sea cave creates a hole)
5. Sea stacks (form when continued erosion of a sea cliff causes arches to collapse, leaving stacks)
203
What are the 6 depositional coastal landforms?
1. Barrier spit (material deposited in a long ridge extending from a coast)
2. Bay barrier (forms when a barrier spit grows
to completely cut off a bay from the ocean)
3. Lagoon (a shallow saltwater body cut off from the ocean by a bay barrier)
4. Tombolo (forms when sediment deposits
connect the shoreline with an offshore island or
sea stack)
5. Beach (the relatively narrow strip along a coast where sediment is reworked and deposited by waves and currents)
6. Barrier beaches and islands (long, narrow depositional features that form offshore roughly parallel to the coast)
204
What are wetlands?
Ecosystems adjacent to the coast that are
saturated with water enough of the time to support hydrophytic vegetation (plants that grow in water or wet soil)
205
What are the two types of wetlands?
1. Salt marsh – consists mainly of halophytic (salt-loving) plants (mainly grasses)
2. Mangrove swamp – form in tropical regions in intertidal areas.
Vegetation is highly tolerant of saltwater inundation but intolerant of freezing temperatures
206
Why is it important to protect wetlands?
High in biological productivity, and provide optimal habitat for varied wildlife
207
Define Eolian
Eolian means "wind"
208
What are eolian processes?
Erosion, transportation, and deposition accomplished by wind
Grain size of airborne particles is important in wind erosion - small particles move easier
Eolian processes work only on dry surface materials
209
What are the two principal wind-erosion processes?
1. Deflation: removing and lifting individual loose particles
2. Abrasion: grinding rock surface by the
“sandblasting” action of particles captured in the air
210
What are the main erosional landforms?
Deflation hollows (“blowouts”) – depressions in
the landscape caused by wind deflation
Desert Pavement – a hard, stony surface commonly covering land surfaces in arid regions
Ventifacts – rocks that are pitted, grooved or polished from eolian abrasion
Yardangs – large-scale streamlined rock structures
211
Why is disruption of desert pavement surfaces an important issue in arid regions?
Desert pavements have a strong impact on water infiltration to function as regulating water resource and supplying water for vegetation growth
212
Define a dune
The deposition of sand grains as transient ridges or hills
213
How are dunes formed?
When saltating sand grains encounter small patches of sand, their motion is dissipated and they accumulate
Once accumulation reaches a thickness of 30 cm, a slipface forms, then characteristic dune features follow:
– Stoss slope – gently-sloping windward side of a dune feature
– Leeward slope – more steeply-sloping (at angle of repose) slipface in downwind side of dune feature
The constant influx of new material causes the dune to migrate
214
What are the main shapes of dunes?
1. Crescentic
2. Linear
3. Star
215
What are the sub-types of a crescentic dune?
Barchan dunes: horns point downward, constant strong winds
Barchanoid ridges: when barchan dunes align
and join into long ridges, constant strong winds
Transvese dunes: long, sinuous, asymmetrical
ridge formed from barchanoid ridge, constant weaker winds
Parabolic dunes: horns point upwind, constant strong winds
216
Describe a linear (longitudinal) dune
Longitudinal dunes: linear ridge, may be slightly sinuous, ridge forms parallel to resultant vector of multiple wind directions, constant strong winds
217
Describe a star dune (radiating ridge)
Pyramidal shape
* Multiple ridges form due to variable wind directions
* Constant weaker winds
* Multiple variable wind directions
* Lower sand supply
218
What is loess?
Clays and silts blown great distances by wind and deposited in unstratified, homogenous deposits
219
When did most loess form?
Left behind on outwash plains formed during
the retreat of Pleistocene glaciers, about 12,000 years ago
220
Why is loess important for agriculture?
Forms fertile soils (well-drained and good moisture-retention), good for farming
