Final Exam Flashcards
What is the definition of geography?
The science that studies the relationships and interdependence of geographic areas, natural systems, and cultural activities
What is spatial?
Term that refers to the nature and character of physical space, its measurement, and the distribution of things within it
Why does geography require a spatial perspective?
A spatial perspective is a way of thinking about how and why physical features/processes are positioned in geographic space
What are the five themes of geographic science?
Location
Place
Region
Movement
Human-earth relationships
What is physical geography?
The science concerned with the spatial aspects and interactions of the physical elements and process systems that make up the environment
Define location
Is specific and absolute, allows you to discuss places in absolute terms
Ex. coordinates
Define place
Is subjective, every place has a distinct group of physical features, and changes over time
Ex. a town or city
Define region
A group of places that have physical features or human characteristics (or both) in common
Ex. tropical rainforest region
Define movement
Animals, plants and other physical features of earth move from one place to another, can be affected by natural barriers
Define human-earth relationships
Humans depend on, adapt to, and modify the world around them: humans and the environment are shaping each other
Describe the process of science (the scientific method)
Six steps:
Observation
Hypothesis/prediction
Experiment, measure, test hypothesis
Analyze results
Peer review
Iteration (conclusion further tested by other researchers)
What is a system?
Any ordered/interrelated set of things and their attributes
Linked by flows of energy and matter
Distinct from the surrounding environment outside the system
What is an open system?
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
What is a closed system?
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
What are the earth’s four spheres?
Atmosphere
Hydrosphere
Lithosphere
Biosphere
What is a negative feedback loop?
Feedback information maintains self regulation, stable condition
Ex. vegetation (temps rise -> enhanced vegetation growth -> enhanced CO2 uptake –> temps rise and maintain stability)
What is a positive feedback loop?
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)
What is geodesy and what is a geoid?
Geodesy = science that determines Earth’s shape and size
Geoid = the unique, irregular shape of the Earth’s surface
What purpose does a reference ellipsoid serve?
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.
Define latitude
An angular distance north or south of the equator, measured from the centre of the earth
Define longitude
An angular distance east or west of a point on the earth’s surface, measured from the centre of the earth
Define parallel
A line connecting all points along the same latitudinal angle
Define meridian
A line connecting all points along the same longitude
Define a great circle
Any circle drawn on a globe with its centre coinciding with the centre of the globe
Where is the prime meridian?
The greenwich meridian (line from the north pole to south pole, through Greenwich, England)
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
Define map scale
A ratio of the image on a map to the real world
What are the three types of map scales?
Representative fraction (1:25,000)
Written scale (1cm=250m)
Graphic scale (a bar scale)
What is a large-scale map?
1:50,000 or less, show a smaller area in more detail
What is an intermediate-scale map?
Intermediate-scale maps are 1:50,000-1:250,000
What is a small-scale map?
Small-scale maps: 1:250,000 and higher, show a greater area in less detail
Define map projection
Reduction of a spherical globe (earth) onto a flat surface (paper) in an orderly and systematic realignment
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)
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
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
What are short-timescale events?
Volcanic eruptions, meteor impacts, landslides
What are long-timescale events?
Mountain building, canyon incision, formation and breakup of supercontinents (plate tectonics), infilling of sedimentary basins
From largest to smallest, what are the intervals of the geologic time scale?
Eon > Era > Period > Epoch
How much time does the geologic time scale break down?
The age of the earth - the last 4.6 billion years
How are boundaries of the geologic time scale determined?
Boundaries are based on major events in earth’s history
How old is the universe?
13.7 billion years old
How are the ages of rocks (and thus the earth) determined?
Through absolute dating that provides the numerical ages of materials
How old are the oldest rocks on earth?
About 4 billion years old
Where on earth are the oldest rocks found?
In Greenland, the Canadian Shield, and western Australia
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
Describe continental crust
Thicker
Mostly granite from volcanic processes
Lower density
Describe oceanic crust
Thinner
Mostly basalt extruded from cracks in earth’s crust
Higher density
What is isostasy?
The state of gravitational equilibrium between the lithosphere and asthenosphere
What causes isostatic rebound?
Recovery uplift of the crust
Ex. after periods of glaciation
What causes isostatic depression?
Crust sinking into the asthenosphere
Ex. by weight of glacial ice during continental glaciation
Define mineral
Nonliving, naturally occurring compound with a specific chemical formula and a crystalline structure
Define rock
An assemblage of minerals bound together
Or a mass of a single material
What are the two most common mineral groups in the earth’s crust?
- Silicates
- Carbonates
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
How do clastic sedimentary rocks form?
Through compaction, cementation, and hardening of sediments into sedimentary rock
(process of lithification)
How do chemical sedimentary rocks form?
From direct precipitation from a water solution
How do biochemical sedimentary rocks form?
From accumulation of shell material, and biological oozes
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
What powers the rock cycle?
Internal convection currents
Solar power
Define continental drift
All landmasses migrate and once (approx 225 million years ago) formed one supercontinent, Pangaea
What are the four lines of evidence for the theory of plate tectonics?
- The obvious fit of the continents
- The same rocks are found on previously adjoining continents
- Fossils of the same organisms are found on now widely separated southern continents
- Paleoclimatology (past climate clues) like glacial striations
What is seafloor spreading?
Areas of oceanic crust where magma upwelling causes it to split
Mid-ocean ridges are seafloor spreading centres
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
How do earthquakes, volcanoes, and hot spots support the theory of plate tectonics?
Most (almost all) of this activity occurs along tectonic plate boundaries
What are the three main types of plate boundaries?
Divergent plate boundaries
Convergent plate boundaries,
Transform boundaries
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
What is relief?
Elevation differences in a local landscape; an expression of local height differences between landforms
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
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
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)
Where is the oldest and youngest crust in Canada?
Oldest - Northern Canada
Youngest - areas of volcanic activity
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
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
What is strain?
Strain is how rocks respond to stress, results in rocks folding (bending) or faulting (breaking)
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
Define orogeny
A mountain-building episode that occurs over millions of years
Describe an earthquake
The sharp release of energy that occurs at the moment of movement along a fault, producing seismic waves
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
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
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
Where does volcanism occur?
At plate boundaries, subduction zones, and hot spots
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
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
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
What is weathering?
The process that breaks down rock at Earth’s surface (and slightly below)
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
What factors influence weathering processes?
Rock composition
Rock structure
Surface and sub-surface water
Climatic conditions
Slope orientation
Vegetation
Time
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