september 5/08
Geography is the study of spaces and places as well as the study of spacial
aspects of human existence
-human geography is: urban and regional planning
transportation
marketing
real estate
tourism
international business
Physical geography : natural resource planning
and the study of global warming, desertification, deforestation,
loss of biodiversity, ground water pollution, and floods and droughts.
Why is what where
what means a physical phenomena
What is Geography?
it is a focus on integration of information
it is a focus on spatial differences
it is a focus on spatial relationships
it provides synoptic (summary) overview
it provides a holistic (complete) view
5 themes of human geography
Location
Relative location- the location of a place relative to other places
Absolute location- the exact location of a place on the earth’s surface
Place
Where things are happening. The Physical aspects of a place, the human
characteristics of a place and the fact that each place is unique.
Regions
connects places w/ similar physical and/or human characteristics
Movement
movement of people and ideas as well as the movements of the elements of the
natural world
Human-Environmental Interactions.
how human connections and activities affect the natural world.
A system is any order interrelated by a set of elements and their attributes linked
by flows of energy and matter, as distinct from the surrounding environment
outside the system.
Sept, 8/08
Negative feedback (good)- a feedback loop which slows or counters a response
to an input to the system and helps promote self regulation (helps keep system in
balance) e.g. natural predator prey relationship
positive feedback (bad) - a loop that tends to increase the effect of an input to a
system and can lead to an increased change e.g. population explosion.
A model is a simplified idealized representation of a part of the real world.
Null-Hypothesis- a hypothesis that needs to be tested
4 open systems of the world
Atmosphere - Thin blanket of air held to the earth by gravity. 32 kms thick but
only the 5 kms next to the surface can support life. contains nitrogen, oxygen,
carbon dioxide argon and other trace gases.
Hydrosphere- All the water in the Atmosphere
surface water
ground water
fresh and Mineral(ocean) water
has tremendous heat storage capacity
Lithosphere - the earths crust
Bedrock, rock and sediment as well as soil
Biosphere all parts of the earth where living organisms can exist
Earth as a geoid
Shape of earth is not perfectly spherical
Shape of earth is a geoid
geoid means earth shaped
Characteristics of the earth.
equatorial bulge- this is because the majority of the earths core is a viscous
liquid. As the earth spins the centrifugal force on the core causes it to get pushed
to the outside and the middle which leads to the circumference of the equator
being about 50 kms longer than the circumference over the poles.
Latitude- an angular distance relative to the center of the earth and the equator
perpendicular to the polar axis and parallel to the equator thus they are
called
parallels
Longitude- measured in degrees relative to the center of the earth and the Prime
meridian which is Greenwich England and was adopted as the prime meridian in
1884
-all flat maps have a distortion
conformity- all angles are preserved but not size or area
equivalence- shape but not area are distorted
UTM- Universal Transverse Mercator Projection
most important projection in the world
world standard for topographical mapping
developed in the late 40’s by the US army
September 12, 08
Geographical Information Systems
GIS
- is a set of tools for collecting, storing, reviewing, transforming, displaying, and
analyzing spatial data
- can also be used to display non-spatial data
it is stored in a data base
it is used to support decisions and for problem solving
G= Geographical
points - cities and land marks
lines- roads, rivers, and boundaries
Areas - climactic, and soil regions
Rasters - information about temperature or clay in the soil.
everything is geo-referenced so it can be over-laid and one map can show lots of
different information
I= Intelligence, Integration, and Information
links b/w the map and the database
S= system
Representations of Geography
features - lines and polygons
surfaces - topographical
networks- points connected w/ lines i.e. utility, stream, river, and road networks
locations - geo-database stores locations as addresses, (x,y) locations, postal
codes, place names, and route locations
image - raster technology is an efficient means of capturing large amounts of
imaged data.
The ultimate objective of GIS is
Problem solving and
decision support
Applications are
transparent
repeatable
defendable
what-if? scenarios (sensible analysis)
sept, 17 2008
photogrammetry - precise measurements from photos- height distance and area
important in map making
3-D info from stereo ( multiple) photos
2 types of Remote Sensing
Passive- uses existing electromagnetic energy to capture mage or photo
(reflected sunlight etc.)
Active systems- has its own energy source. Send energy to target area and then
detects its return. i.e. radar and lidar. it is not dependent on sunlight and can
capture images any time of day or night and in any weather.
2 types of Data - Analog (photos) and Digital (images)
it is possible to convert both types back and forth to the other kind.
Different targets reflect energy in unique ways and at different wavelengths.
these spectral signatures are used for the identification and classification of
areas.
Sept, 22 2008
Economic Geography studies how people earn a living, how livelihood systems
vary by region and how economic activities are interconnected in space.
GMT has been replaced by UTC or Universal Coordinate Time and uses a
atomic clock.
Prime Meridian is the basis for both the GMT and UTC
“science-based” decisions are also political decisions based on economics social
relations ad technological change.
GMT originated with british railways in 1847
World system of time zones proposed by Canadian Sir Sanford Fleming in 1873
1884 in Washington DC 25 Nations agree on Greenwich as the Prime Meridian.
Most Countries have accepted and use time zones by 1929.
IN Canada Provinces have jurisdiction over time.
Time may be defined and measured scientifically but the Map of time is a human
and social science creation.
Sept, 24 2008
(Pop 2000-Pop 1999)/Pop 1999 * 100 gives you percentage of pop change
you can have growth w/o development
Location location location. Coalhurst survives even with no development because
it is only 10 min from Leth and is a satellite suburban that depend on leth for
employment, shopping, and services
Residents choose Coalhurst for its lack of development. In this case Dependancy
relationship is an asset.
Regional Development depends on scale of analysis;
Micro- scale diversification, commercial self sufficiency, social and physical
infrastructure and sustainability
Macro-scale share of the worlds wealth, social well-being, and human potential.
Primary sector
Agriculture
Forestry
Mineral extraction
Producing raw materials
Secondary
Transformation of raw materials into consumer goods
Manufacturing
construction
power generation
processing
Tertiary
Retail and wholesale trade
services and Business (FIRE)
transport/utilities
FIRE- Financing, Insurance, Real Estate
Quaternary (information)
education
government
communication/media
Developed nations usually have 50% or great employment in the service/tertiary
industry.
Undeveloped nations usually have 50% or greater in the Primary/raw materials
industry
GNP- Gross National Product
The Value of goods and services produced by the residents and firms of an
economy in a given year regardless of their location
GNP is a measure of the value of output produced by people and firms of a
region
GDP -Gross Domestic Product
The value of a nations goods and service production in a given year within a
nations physical borders
GDP focuses on where a good or service is produced not who produced it
GNP and GDP Gross means not adjusted for depreciation
PPP Purchasing Power Parity (in US$)
a measure of purchasing power that takes into account the relative cost of living
and inflation rates in different countries.
Sept, 26 2008
Neoclassical economics become the dominant paradigm of modern economics
Clark and Fisher rebelleled against the dominant classical tradition of David
Ricardo and John Stuart Mills
Clark and Fisher founded the type of economics we use today.
Clark-Fisher model is driven by
differential rates of productivity growth in agriculture, manufacturing and
services
Engel’s law and consumer spending as a society becomes wealthier.
There are measurements we can make other than GDP/GNP, Employment and
Income to gauge economic development.
Human well being - based on some measure of good health, ability to participate
fully in society and access to material goods.
Gender empowerment - measure of inequalities b/w men and women
opportunities in a country
political participation and decision making
economic participation and decision making
power over economic resources
Dependancy Theory
Marxist theory originating out of latin america
core and periphery concept
Development of the core comes at the expense of the periphery
colonialism and exploitation by imperial powers (core powers)
neocolonialism and exploitation by Trans-National Corporations.
underdevelopment is an active and ongoing process
uneven exchange of low value resources for high value manufactured
goods
wealth and development of the global core is a product of the poverty and
underdevelopment of the periphery
Sept, 29 2008
Behavioral geography is
an approach to understanding human geographical behavior
it draws upon research findings in psych, but also economics, sociology and
anthropology
focuses on the cognitive processes underlying spatial reasoning, decision
making and behavior.
behavioral geographers study
Way finding (route selection)- where sidewalks go on campus
Attachment of Place - Home versus where you are living (home)
Perception of spaces and places- a long ways in Germany vs Canada
Location decisions - where we want to live in relation to what we want to do
resource allocation- when a farmer decides what to plant in each field
2 applications of behavioral approach
Agricultural land use decisions
differences in spatial skills
Geography was formalized as a educational discipline in 1847 in Germany and
was used for its military applications
Environmental Determinism ( the theory that those living in the mid northern
latitudes were superior to others) was the first paradigm to dominate human
geography.
it was rejected b/c
it couldn’t be empirically verified
there were too many anomalies
it was overtly racist ( used to justify imperialism)
Oct, 1 2008
following the demise of Environmental Determinism the regional perspective (RP)
dominated geographic thought
RP emphasized detailed study of a specific region, synthesizing knowledge from
many systematic disciplines.
emphasized areal differentiation - what makes a region unique or distinctive and
allows us to differentiate b/w it and another region.
This definition doesn’t include and reference to explanation, prediction, search for
laws or empirical verification.
RP wasn’t regarded as a science and wasn’t taken very seriously
during WWII many regional specialists lacked competence in topical and
systematic subjects. and it was decided that geography should shift focus from
general to specific (systematic focus)
geography adopted the basic objectives of science and also the language,
methods, and the techniques of science.
positivism - everything that matters can be measured
Homo Economus- maximized utility while minimizing expenditures.
Neo-classical economic determinism dominated human (economic) geography
until the late 60’s
Predictions grounded in optimization, the principal of least effort or profit
maximization were found wanting- too many anomalies.
eg how do we explain decisions that are good enough (feasible) but not the best
choice (optimal)
Simon’s Satisficer Theory - we are rational decision makers, even when the
decisions we make are sub-optimal.
the Central idea of SST is - when we make decisions, we take a range of
considerations into account.
Oct 3 2008
Environmental information => Perceptual filters => cognitive map.
Personality, experience, culture, gender, class, and ethnicity are all examples of
perceptual filters.
Behavioral Geography (BG) is only one of several approaches used to
understand human geographic behavior.
the behavioral approach questions range from way finding to resource allocation.
BG was developed in response to limitations in neo-classical environmental
determinism
BG has close ties to psychology, but other disciplines as well
BG in land use
Rent Theory- any given parcel of land will be used for the highest and best use
(most profitable) advocated by JH von Thunen in 1842
Thunian land use patterns widely documented but not universal
Ag land use patterns deviate from ideals b/c maximum profit is not the only
factor.
farmers also take into account 4 other factors
Intrinsic - an activity valued in its own right
Expressive- a means of self expression
instrumental - means of earning an income
Social - done for sake of interpersonal relationships.
Spatial skills are
Spatial orientation - the ability to imagine how an object would look like from
another perspective
Spatial Visualization - the ability to mentally manipulate an object (mental
rotation)
Spatial relationships - ability to identify and analyze spatial patterns and
associations.
Gender-related differences in spatial skills
women are underrepresented in jobs requiring application of spatial skills
some argue that this is b/c women’s spatial skills are inferior to mens.
Theories advanced to account for gender differences
Deficiency theory - differences are biologically based (genes)
Difference theory - differences grounded in sociocultural process
inefficiency theory - performance and behavior indicators used tend to favor
males.
Oct 6 2008
Urban Geography UG is the intersection of Urban Anthropology, Urban
Sociology, Urban economics and Urban PLanning/Architecture.
what makes UG different is its focus on spatial variation/ areal differences
Inter-Urban -studies system/networks of cities and towns. Cities and towns are
treated as individual nodes in a network.
Intra-Urban- study of the internal structure and characteristics of cities and towns.
Social patterns and process’s of cities.
Intra-Urban geographers look at:
economic geography
transportation geography
social geography
cultural “
political “
morphology
Planning
There are links b/w these studies
The spaces/geographies/differences within a city are the product of both social
structure and individual behaviors
Key ?’s
How is our society/social structure represented in different ways w/i a city?
Does the city “reflect” different social structure features in different ways?
spatial variation
different patterns and organizations
spatial inequalities and segregation
Can we identify spatial variations?
Main features that differentiate people/households in Canada
education
Income
ethnicity
visible minorities
family type/size/number of children
Age and family status (aging society, young adults, young families, empty
nester’s)
poverty
migration
Social Structure is not a state but a dynamic (it changes over time)
Household formation
marital status
lone parent families
labour force participation
impoverishment/homelessness
erosion of the middle class
we can get data on social structures via government census’s
Oct, 8 2008
Census Tracts are the areas or regions of a census. it is small and stable usually
have a pop of 2500 to 8000
Census’s give us objective data (how many kids, religion, single parent homes)
but not subjective data (how we feel about our neighborhood)
Spatial variation is the search for spatial order/patterns and organization or
randomness
uniform distribution = spatial in-variation, uneven distribution = spatial variation
thousands of urban social indicators could be mapped and studied for their
spatial variations
Important questions
Which indicators have similar patterns?
Which indicators have opposite patterns?
which set of indicators have very different patterns to other sets of indicators.
These 3 questions are called the study of spatial covariation
positive spatial covariation - similar patterns or variations b/w different
measurable indicators. (income, family type)
Some social attributes (indicators) have opposite distributions and patterns.
Some social attributes have very similar distributions and patterns
Some social attributes are part of the same general and separate social structure
features.
Do the same trends emerge in most cities in N.A.? (this is the fundamental
objective of science) Yes they do.
Different patterns for different social structures i.e. generalized/consistent pattern
recognition.
A model is and idealized representation of reality
A model tries to simplify the complexity of the real world
A model is a generalization
Social structures change thru time as do geographical representations which
result in new forms of social/spatial variation.
Oct, 10 2008
Economic status is Sectoral in a city, family status is concentric zonal and ethnic
status is multiple nuclei.
Social structure has multiple organizations
Human agency- the individual and collective decisions, actions, choices, ect. of
humans. It is interested in peoples behavioral traits
affect - psychological term that deals with emotions and feelings.
we can identify unique structures of affect just as we can cognitive structures.
there is spatial differentiation in human experience as well, it is not just limited to
structure.
MIDTERM TO HERE
Oct, 15 2008
weather and climate
western canada gets about 1 F3-F4 tornado a year.
almost all natural disasters are a result of weather and climate.
temperature - a measure of the heat storage in a substance or matter.
Radiation - the way we get nrg it comes from the sun in the form of electromagnetic radiation.
The earths albedo - the estimated reflection of solar radiation.
clouds - 20%
earths surface - 4%
aerosols - 6%
result is about 30% albedo
Humidity - measure of water content in the air
Dew-point temperature - Td - temperature at which cooling air reaches a
saturated state. no additional water -very important
Vapor pressure - pressure on a surface due to the mass of H2O in the air. Water
storage in air as a function of temperature and is non-linear as it is exponential.
this is why the Arctic and antarctic are deserts
clouds form from convection and always form above the Td.
topographically driven clouds are orographic as they rise above a mountain
range or sink into a valley they lose or gain water content. these type of systems
are about 150km large
convergence of air. air moves to a low pressure from all directions and is forced
up this causes lots of precipitation. 500km system
Lifting along weather fronts- warm air has to travel over the denser cold air front
in both directions. these systems are about 1500km large.
Oct, 17 2008
ice crystal patterns
0-1000m - liquid water only in the clouds
1000-7600 - mixed water and ice. temp -20*C
7600m and up - ice only
Atmospheric motions
Horizontal motions
persistent long-lived (seasonal) patterns =General circulation
short patterns are storm cells
pressure gradients - the rate of change of pressure w/ distance.
Coriolis force - it is the apparent deflection of wind and air masses. it is due to the
rotation of the earth. In the Northern Hemisphere the air rotates to the right. in the
southern hemisphere air rotates to the left.
Friction forces - stresses b/w the moving air and the surface of the earth and also
b/w parcels of air moving in different directions.
the atmosphere has three cells of circulation.
Oceanic flow - generally water flows along the equator from south america to
asia.
ENSO - El Nino southern oscillation - the pacific ocean reverses direction in the
southern hemisphere and pushes warm water up against South America.
Humans have no idea why this happens
la Nina - extremely strong current pushes water from SA to Asia before it has
time to warm up this results in colder global temperatures.
Both El Nino and La Nina have global weather implications.
There are 4 types of air masses
cold- polar
warm- tropical
wet- maritime
dry- continental
Pineapple Express - a warm very wet air mass that shoots like a missile from
around Hawaii to north america and dumps a massive amount of water on the
local area it is directed at.
Hurricane - a tropical storm with winds above 119km/h. The storm surge is the
deadly part of a hurricane and can be 9m above high tide mark.
Oct 20 2008
Hydrology is the science and the study of water.
Water demand is increasing through global population growth and industrial
expansion.
Water pollution is increasing for the same reasons.
Climate change is leading to an increase in droughts is some areas and floods,
which increase water pollution, in other areas.
There can be 3 problems with water
Too much water - floods
Too little water - drought
Water is too dirty - pollution
- 97.22% of the earths water is salt water
2.78% is fresh water
Of that 2.78% fresh water 2.15% or about 3/4 is locked up in glaciers and a little
under 1/4 of it is ground water.
Only about 0.02% of the earths water is fresh surface water.
Most rain water is lost directly back to the atmosphere.
water that doesn’t evaporate becomes either surface or ground water.
Interception - capture of precipitation by the plant canopy and its subsequent
return to the atmosphere before it does anything useful.
interception values range from 2 to 7 mm per rain event.
Plant transpire through stomata.
Potential Evapotranspiration - the amount of water that CAN be expired IF there
is an unlimited supply of water.
Actual Evapotranspiration - the amount of water that is actually lost. it is smaller
that PET due to water limitations.
AET = PET only in tropical areas
AET is used to define the demand for additional water (irrigation)
Runoff - surplus water runs off as surface runoff. Runoff occurs when rainfall
intensity exceeds infiltration capacity.
Ground water feeds into river resulting in base flow. Ground water moves very
slowly sometimes only a kilometer a year.
Drainage Basin - the area that feeds a stream or river
Oct, 22 2008
during and after a rainfall event water moves downslope as sheet or overland
flow.
surface runoff concentrates in small rills which can become gullies which can
become stream channels.
Soil Water
pore space - in all soils most of the total volume of the soil is actually pores which
can be filled with either air or water.
Field Capacity - the maximum amount of water a specific soil can hold against
gravity.
wilting point - water content of the soil below which plants cannot extract water
and will die
Loam has the highest amount of available water and sand which has the largest
pores and clay which has the smallest pores both have the lowest amount of
available water.
The Water Balance Equation
Precipitation = Actual Evapotranspiration + Surplus +/- Change in soil moisture
storage.
Arid Regions
PET > Precipitation (moisture deficit)
Humid regions
PET < Precipitation (moisture surplus)
Climate in the Prairies is Semi-Arid
in winter PET < P
in summer PET > P
ground water recharge can only happen when the surface soil is saturated.
porosity = volume of voids in soil or rock
Permeable layer - pores are large and connected
Aquifer - rock layer which allows groundwater flow that is so high we can
continuously extract water from it.
Inpermeable layer - pours are so small that water has difficulty penetrating it and
flow within the layer is so slow it is insignificant.
Oct, 24 2008
the water table is the surface of the saturated zone.
cones of depression occur when water is drawn out of the saturated area via
pumping and the saturated zone is not recharged.
low pressure irrigation is much more efficient than high pressure long range
irrigation.
water pollution is any physical, chemical, or biological change in the water quality
that adversely affects living organisms or makes water unsuitable for desired
use.
the leading pollutants are
sediments
bacteria
nutrients
metals
factories, wastewater treatment plants, old landfill sites, abandon mines,
under/above ground storage tanks are all examples of point source or
concentrated pollution.
non-point source pollution comes from agricultural practices (over fertilization,
pesticides, manure) and from lawns, gardens and golf courses and street runoff.
livestock manure is considered to be one of the main ag contributors to water
quality degradation.
Water quality has 3 main categories.
physical
chemical
biological
water temp. is very important
affects physical, chemical, and biological characteristics
the warmer the water the less O2 can be dissolved in it.
the higher the altitude the lower the DO
too many nutrients (P,N) result in prolific plant growth. the plants then die and
must be decomposed- the process of decomposition uses the O2 in the water
and fish and other plants die from a lack of O2
Climate change impacts:
may lead to an increase or a decrease in precipitation depending where you are.
warmer winter temps lead to less snow pack, less spring runoff and reservoirs
may not fill in the spring.
there will be warmer over all temps
more extreme weather events.
Canadiens are the largest water users in the world 326L/day
the Aquifers (especially in the US Mid west) are being over pumped b/c current
irrigation methods are unsustainable.
Oct, 27 2008
uniformitarianism - the same physical processes active in the environment today
have been operating throughout geographical time.
Superposition - youngest rocks and sediment layers are on the top and the oldest
layers are on the bottom.
the earth is 4.6 billion years old.
if the earths history were compressed into one year humans didn’t show up until
about 11:00pm on Dec. 31 and written history is really only one minute before
midnight.
the earth has a solid inner core and a liquid outer core.
both the inner and outer core are made up mainly of iron. The inner core is only
solid because of the pressure exerted on it.
The solid lower mantle is beside the outer core. and the partially molten upper
mantle is between the lower mantle and the earths crust.
the upper and lower mantle compromises 80% of the earths volume. The deeper
you go the hotter it gets.
beneath the lithosphere is the asthenosphere which is where magma is found.
the continental crust is thicker and heavier, pushing the upper mantle down this
is called isostatic adjustment.
the oceanic crust is thinner and lighter than the continental crust.
Endogenic (internal) system - builds landforms through lifting, from internal heat.
Exogenic (external) system - wears land down through weathering and erosion.
this constant lift and denudation is called the geographical cycle.
a mineral is an element or a combination of elements that form inorganic
compounds.
a rock is a combination of minerals bound together.
Oct, 29 2008
rock that solidifies and crystallizes from magma is called igneous rock
the slower the magma cools the larger the crystals that are formed
Granite is formed from slow cooling magma and is an intrusive rock (slow rising)
extrusive rocks come to the surface of the earth quickly and cool quickly forming
light rocks with many air bubbles example is Basalt.
Sedimentary rock always has visible layers. thats its defining characteristic.
sedimentary contains debris form other rocks and organic materials. it forms into
rock by extreme pressure of sediments on top of it or by chemical solutions that
cement it together example is limestone.
coal is formed by vegetation that couldn’t completely decay.
oil forms from marine plants and animals that die in stagnant water w/o oxygen.
they don’t decay and form oils.
deposits of gas are found near oil b/c gas is given off in the formation of oil.
metamorphic rocks are formed when sedimentary or igneous rock are put under
extreme heat or pressure. limestone turns to marble is an example.
Plate tectonics was first advanced by German meteorologist Alfred Wegener in
1915. he never lived to see his idea accepted.
The earths crust is made of large pieces floating on the asthenosphere
fossil evidence puts similar plants and animals on different continents supporting
the theory of pangea and continental drift.
Sea floor spreading - happens along the mid-ocean ridges. the sea floor is
spreading in opposite direction. Magma rises and builds new sea floor. there is
no sea floor older than 200 million years old.
Pangea the super continent that all continents today were once part of.
When the continental crust and the ocean crust collide the ocean crust slides
under the continental crust and melts.
Orogenesis - birth of a mountain. mountains form where plates are meeting and
colliding. The rocky mountains are very young mountains only 40-80 million
years old.
Oct, 31 2008
the are three types of crustal collisions
ocean - ocean
ocean - continental
continental - continental
The Andes are the worlds longest mountain range and follow a oceanic continental subduction area in the pacific ocean.
Subduction Zone- where one tectonic plate is forced under another.
when rock formations are put under stress they fracture into faults this usually
happens in areas of crustal movement and are associated with earthquakes.
The richter scale is logarithmic 5.0 is ten times more powerful than a 4.0 and 100
times more powerful than a 3.0
the longer the time b/w earth quakes the stronger the next earthquake will be.
Calderas are formed when the magma collapses after an eruption forming a lake.
There are about 1300 volcanoes on earth and 600 active ones.
effusive eruptions - gentle eruptions producing large amounts of lava they are
often called shield volcanoes for their distinctive wide flat shape. Hawaii is en
example.
explosive eruptions - occur along subduction zones, gasses and magma are
trapped beneath the surface of the earth and pressure builds until they explode
like a bomb. Mt St. Helen’s is an example.
Dykes are formed by magma that rises but doesn’t make it to the surface and
then cools and solidifies years later when the softer rock and sediments around
them are removed these pillars of stone are left standing.
Nov, 3 2008
Geomorphology is the science of landforms
Denudation - any process that wears away or rearranges landforms. processes
include.
weathering
erosion
mass movement - landslides
transportation and deposition
moving water = fluvial geomorphology
moving air = aeolian geomorphology
moving ice = glacial geomorphology
moving waves = costal geomorphology
Gravity works on all four agents of geomorphology
the lowest level the denudation process can erode to is called the base level
ultimately base level is the sea floor but there are many local or temporary base
levels b/c of resistance, climate, and local relief.
3 factors of denudation
climate - in humid climates, streams may be the primary agent of denudation. in
Arid regions wind is usually the main agent. Glacial denudation can move
massive amounts of soil and completely transform a landscape. climate controls
vegetation cover which protects the surface from erosion.
Geology - some rock types such as granite are very hard and harder to erode
where as soft rocks like shale of sandstone erode easily and form smaller
sediments. steep surfaces are the result of hard materials.
Relief - transportation of weathered material by gravity depends largely on the
slope of the land. gravity is important as is friction and inertia. Hill-slopes are
concave with soft fine material at the base.
when a slope is in disequilibrium (too steep) and becomes saturated Land slides
happen.
bedrock= parent rock
parent rock = material from which soil develops
joints = fractures in rocks where the weathering process can break rock further
down
Rigolith = weathered rock that is not yet fine enough to be sediment.
Physical weathering - mechanical breakdown, there is no alteration of chemistry,
dominates in drier cooler climates. Includes breakdown by plants.
Chemical weathering - chemical processes change the parent material. It
dominates in warmer wetter climates.
both processes are usually happening at the same time.
Crystallization - minerals dissolve in rain, water crystallizes and breaks up small
particles of the rock surfaces.
Hydration - water is absorbed by minerals of a rock surface, minerals swell and
break apart.
Frost action - most important and common form of physical weathering - water
penetrates cracks, freezes and expands which weakens the rock and can cause
it to break apart. Freeze-thaw action.
plant roots can split rock formations
frost action loosens and frees rock forming a talus slope on a mountain
(accumulation of rock debris from a rock fall)
chemical weathering happens in the presence of water. it is the decomposition
and decay of minerals. it is a chemical alteration of the rock. Acidic rain
accelerates the process.
spheroid weathering - water penetrates joints and fractures them. it dissolves the
cementing material resulting in rounded edges.
hydrolysis - minerals chemically mix w/ water resulting in new minerals.
oxidation - rusting - oxygen in water reacts with metallic elements within rocks.
Carbonation - water reacts with Carbon dioxide in the air and creates carbonic
acid. It dissolves limestone and some other minerals
natural rain water has a pH of 5.6 (acidic)
Nov, 5 2008
Aeolian denudation (wind) creates desert pavement b/c the wind carries all the
fine sediment away leaving only the pebbles and larger rocks tightly fitted
together on the surface.
Yardangs are rock formations created by mechanical erosion by wind
sandblasting soft rocks.
tides are caused by the gravitational pull of the sun and the moon
gravitational pull pulls the earths atmosphere, oceans and lithosphere on the side
facing the sun or moon.
as the earth rotates eastward the tidal progression appears to move westward
but it is just the earth spinning under the water high tide always faces the moon
and sun.
there are two high and low tides a day. 2 tide cycles take 24 hrs 50 mins to
complete.
tide range depends on the shape of the sea floor and the coast line.
the large amounts of water moved back and forth by the tides can be used for
power generation.
currently there are only 3 active tidal power plants in Russia, France and Canada
but 30 sites world wide have been identified as suitable locations
Sea level rise + Spring tide = costal erosion
humans increase the rate of denudation by
clearing forests
developing cultivated land
damming streams
building cities
creating air pollution
changing ground water levels
Acid rain - effects can be felt far away from the pollution source. it accelerates
chemical weathering. Knows no boundaries as it is carried by the wind all around
the globe.
mass movement is denudation that happens abruptly and is very fast movement
of soil and rock.
soil creep has a terracing affect the evidence of soil creep can be seen in tree
trunks that change angle of growth and leaning fence lines as well as terraces.
Nov, 7 2008
Q= W H V
where q is discharge, w is width, h is height and v is stream
velocity
the higher the velocity, the higher the carrying capacity for sediment.
carrying capacity is the maximum load that a stream can transport at a given
velocity. If carrying capacity is greater than actual load then erosion occurs.
Dissolved, suspended and bed load make up the actual load of a stream
bed load is the larger sediments and rocks that roll along the stream bed.
meandering streams develop on gradual slopes and gave a sinuous shape.
stream gradients are concave in shape. A grade stream stream condition occurs
when the stream reaches a dynamic equilibrium.
discharge of a stream is constant from place to place and is expressed by Q= AV
where a is area and v is volume.
nick-point is the lip of a waterfall. Waterfalls always retreat from the edge
Niagara falls retreats 1.3m per year and has taken 12,000 years to reach its
current position.
Nov, 10 2008
READ CHAPTER 11
glacier a body of ice and firn lying wholly or partly on land and showing evidence
of present or former motion due to gravitational forces.
firn - not ice but not snow it is like soft ice and is usually what the top layer of
glaciers are made of.
glaciers are very good climate recorders and regulators. they are landscape
changers and sediment suppliers
Glaciers store 70% of the earths fresh water and cover 11% of the earths
surface.
glaciers get larger from accumulation which comes in the form of.
solid precipitation - snow
avalanches
wind drifted snow
rime ice - water vapor freezing on contact
superimposed ice - refreezing of melted water
- metamorphosis - turns snow into water. the increase in density happens
because of heat and pressure.
glacial ice isn’t pure ice. it has polycrystalline ice, meltwater, gas, sediment and
other impurities
ice can be
cold = below its pressure controlled melting point, there is no water present
in the ice.
warm = above the pressure controlled melting point, there is water present
in the ice.
glaciers are categorized as
polar - cold ice throughout
temperate - warm ice throughout
poly-thermal - warm based in the inner regions with cold ice on top.
Niche glaciers/glacieretes - very small glaciers about 100m square
Alpine glacier with tributary - larger than niche glaciers
Mountain glaciers - larger than alpine glaciers and have multiple tongues.
Ice Cap - glaciers on top of mountains with a radial flow.
Tidewater/calving glaciers - glaciers that end in water, the tidal action breaks up
the end of the glacier creating icebergs.
Piedmont glacier - glaciers that expand out of valleys look like duck feet.
Rock glaciers - glaciers that have more rock in them than snow.
Glaciers ablate from
surface melting
internal melting
basal melting- friction against surface causes heat and therefore melting
evaporation and sublimation
calving - both wet and dry.
glacier mass balance is calculated by the formulas
Kg*m^-2*a^-1 or
m(we)*a^-1
meters water equivalent
Nov, 12 2008
Albedo is the ratio of reflected to incident spectrally integrated solar radiation.
glaciers flow to distribute their mass down glacier
large accumulation = higher flow rates, more erosion and transportation.
Internal deformation - when the bottom of the glacier is frozen to the ground. it
happens because of the weight of the glacier and is the main cause of glacier
movement
plastic - bending or folding of the glacier
brittle - breaking or faulting of the glacier that causes crevasses
Basal sliding - water underneath of the glacier lubricates the surface and allows
the glacier to slide down hill.
Soft bed deformation - mud/slurry underneath the glacier is squeezed out from
under it from the weight and the glacier moves into the spot where the mud used
to be and thus moves down hill.
glaciers, like rivers flow the fastest on the top in the middle where there is the
least friction from the side walls and base.
the thicker a glacier is the more it sides.
flow varies with time
long term and random variations
season variation
kinematic waves
surges - internally triggered, only from unstable glaciers. glacier will travel at
a normal pace for years and then suddenly for an unknown reason flows 10 to
100 times faster for a few years.
Nov, 14 2008
For test know flow variations through time how thick the ice is in polar ice sheets
and how much the see will rise read chapter 11 for sure and know the pictures.
June to early july is the fastest flow period for glaciers.
for sure we will see 1m sea level rise but we may see as much as 4m.
surge type glaciers have non-random geographical distribution.
hazards related to surge type glaciers
outburst floods
iceberg discharge
advancing fronts
landslides
Glacial Erosion, Transportation, and Deposition of Sediments
Glaciers scraped away the bedrock ate a rate of 1mm/year.
the grooves the glacier creates are called straie and show us the direction the
glacier was traveling.
U-shaped valley’s are the result of glacial erosion.
glaciers have affects on mountains as well. Ar(e accent circumflex)te (Arete) are
ridges cut by glaciers that lead to the horn of a mountain.
Paternoster are strings of lakes on a mountain side.
glacial erratics like the Okotoks big stone are a deposition feature.
Roche Moutonne`e are mountains with a very smooth polished side. this was
done as the glacier flowed up that side of the mountain. the other side is very
jagged as the glacier flowed down it it tore large chunks of the mountain away.
there are three types of transported sediments.
supraglacial - transported on top of the glacier, can be massive as they
never get broken down
englacial - in the middle of the glacier, broken up some into smaller stones
and larger sediments.
subglacial - underneath the glacier, make up the smallest sediments like
clay as they are ground so fine by the weight of the glacier.
medial moraines are in the middle of a glacier and lateral moraines are on the
edges of the glacier.
glacial deposited sediment is called Till and it is unsorted. (large and small
particles are mixed all together).
the stones left behind by glaciers are jagged as they have just come out of a
crusher.
the oldman coulee and others like it were formed by a large lake breaking the
glacial dam that was holding it back and flooding the landscape.
Drumlins are streamlined till ridges shaped parallel to the direction the glacier
was flowing. they sometimes have a rock center and are a depositional feature.
permafrost zones coincide with areas that don’t get warmer than 10 degrees C.
periglacial (permafrost) landforms
pingo - and ice thrust hill from the expanding water underneath
ice wedges
patterned ground - polygon shaped chunks of land with ice wedges in b/w
that expand and contract.
global sea levels are now 120m higher than they were in the last ice age.
ice cores are our best record of ancient climate.
the oldest ice in the world is in Greenland and is 80,000 years old. there are over
100,000 glaciers in the world.
TEST 3 COMES TO HERE
Biogeography Nov, 17 2008
the study of life and the distribution of organisms on the the planet from the past,
present, and future.
it integrates the four spheres of geography as well as including anthropologic
influences.
biogeographers look from the individual up to the population => community =>
ecosystem => biosphere.
habitat - the type of environment in which a species resides.
Niche - the role or functional position of a species w/i the community of an
ecosystem.
competition - the intra/interspecific relationship that occurs when commodities
are scarce.
trophic levels - levels through which energy flows. At each level the is a loss of
energy.
Autotrophs (plants) are the foundation of the trophic hierarchy.
there are three types of Photosynthesis
C3 pathways
C4 pathways
Crassulacean Acid Metabolism
the highest rate of photosynthesis happens on bright cloudy days as the suns
rays are dispersed in all directions next highest rate is bright sunny days and the
lowest amount is on dark cloudy days
Plants respire CO2 to the atmosphere all the time but during the day they
photosynthesis more than they respire.
Net ecosystem carbon exchange - is the total storage of CO2 and expiration of
CO2 from a system. Systems can be either sinks or releasers.
Updrafts coming up off the ground during the day are low in CO2, warm and
humid.
downdrafts are high in CO2, cool and dry air.
Heterotrophs - organisms that derive their energy from autotrophs or other
heterotrophs.
Nov, 19 2008
where it is cold, pollutants break down much slower. this is why we find higher
concentrations of pollutants in the sub-arctic, arctic and antarctic.
climate is the main determiner of biomes and their distribution.
the sun shines on the equator and warms the air, forcing it to rise. winds from the
mid latitudes converge on the equator forcing the warm moist air up even higher.
This is why there is so much rain in the rainforest which are right beside the
equator.
deserts boarder the rain forest as the air has been depleted of its water as it was
forced up, but it is still very warm.
the southern hemisphere doesn’t have boreal forests and broadleaf biomes as
there isn’t enough landmass.
w/ an increase in precipitation there is a diversification of vegetation in warm
climates.
Biomes are very predictable both in where they will occur and what they will have
in them based on climate.
there is a missing CO2 sink somewhere in the world as with the amount of CO2
we are producing the atmosphere should be gaining CO2 faster than it is.
Anthropogenic biomes map the earth based on climate and human pop/activity.
over time plants allow larger plants to move into an area and grow. Grasses lead
to shrubs lead to softwood trees lead to hardwoods if the climate allows it.
Aquatic succession - over time sediments fill the pond in until all the water is
displaced and vegetation fills over.
annual temperature range in the rainforest is very small (2.2 degrees) and the
annual rainfall amount is massive almost 3000 mm.
tropical rainforests have different height levels
the shrub (ground) and the upper understory both receive very little light
the canopy is the thickest and most dense part of the forest. it is the area of
the most carbon uptake.
the emergents are very tall trees (up to and over 60 m) that shoot through
the canopy to get the maximum amount of sunlight
nutrients are really only found n the to 15 cm of the rainforest floor as turn over of
nutrients is so high. This is why tropical slash and burn farmers must keep cutting
down forest as the land is only productive for a few years.
cloud forests are rainforests at high enough elevations they are enveloped in
clouds.
Nov, 21 2008
climate change affects tropical areas the least as the have the least temp
change.
cloud forests are the highest forests in the world. they are very thick and dense
with short trees.
Above cloud forests is the paramo plants in this zone are specialized to withstand
frosts. mostly grasses along with a few other stunted sturdy plants.
in the tropics there is a lot or agricultural development in the paramo as it is the
only area with thick enough soils to really support it.
hemiparasites like mistletoe steal resources (carbon nutrients water) from a host
plant.
The African Savanna has an extremely wet season and an extremely dry season.
it is the transition zone b/w the wettest and driest areas on earth.
Subtropical high pressure zones = deserts.
deserts can also be found outside of the subtropical high pressure zones. They
can be in mountain shadows, interior continents (so far away from the ocean)
and Costal deserts like in Chile. Cold oceans sit beside warm land.
Chaparral - Mediterranean like climate although it is found all over the world.
Xerophytic shrubs can withstand long dry periods as precipitation only comes in
the winter.
Temperate rainforests - most found in North America from northern california to
alaska. receive massive amounts of water during the winter w/o freezing, doesn’t
rain much in summer. Largest trees in the world.
temperate broadleaf forests - forests that drop their leaves in the winter as it is to
cold. Precipitation comes in every month of the year and is never heavy but is
reliable.
Midlatitude grasslands - about 400ml of rain a year and an average temp of only
5 degrees.
Boreal forests - both northern and southern. are cold forests with deciduous
trees. Largest biome in the world. has very abrupt edges
Tundra - a very short (2-4 weeks) growing season combined with very cold
temps means that the vegetation is short and flat. Mostly mosses lichen and
shrubs.
temp decreases w/ increases in elevation and precipitation increases.
Nov, 24 2008
Archaeology - the study of past human culture and society through the analysis
of material resources. Resources can be from a few million years ago or a few
moments ago.
Archaeology is a geographical discipline b/c it brings together physical and
human dimensions in an area.
strato(composite) volcanos - are the most intense and destructive type of
volcanos. The wind can carry ashes of these volcanoes thousands of kms.
decay rate of radioactive potassium into stable argon 40 has a half life of 1.25
billion years. with this knowledge we can date ash that we find anywhere in the
world. we can also identify which volcano it came from.
obsidian - volcanic glass created when lava cools so fast that no air pockets
form. It is extremely dense and can make a finer cut than a stainless steel
scalpel.
obsidian can be sourced from which volcano it came from and its age.
archaeology can be connected with the geomorphologic process as exogenic
and endogenic forces lift or expose past human settlements and activities.
law of superposition - the geomorphologic process covers the surface in layers
so that the bottom layers are older than the layers on top of them.
that being said the layers are not flat or always easily defined as human or
geomorphological process can result in uneven layering.
loess - wind-blown silt.
archaeologists dig very systematically so they can keep both chronological and
geomorphological formations and information in context and accurate.
130,000 years old is the age of the oldest neanderthal artifact found in a Belgium
dig. the next was 110,000 years old.
When we link the climactic and stratigraphical data we can see that neanderthals
in belgium survived the last ice age.
Nov, 26 2008
oldest human artifacts found in north america are 13000 years old..
Beringia - the land bridge linking Asia with North america. sea levels were up to
90m lower during the last ice age and thus people were able to walk across from
russia to Alaska.
The ice free corridor even though it was at high latitudes was free of ice b/c of
precipitation patterns.
At times the ice free corridor which ran between the laurentian and cordilleran ice
sheets did ice over. we know that it was 18000 years ago at the hight of the ice
age.
Coastal migration theory - the theory that the first people to arrive in north
america followed the coast down in boats to the ice free areas of california. There
is no evidence to support this theory.
clovis - first culture of people to come to north america. they were following the
large animals that they hunted for food.
Holocene - begins 10000 years ago and lasts till right meow.
pleistocene - period before the holocene.
soil preservation of archaeologic artifacts depends on soil type, acidity and
alkalinity.
Horizon A - decomposed plant and animal matter. it is the start of the soil.
Horizon
O- topsoil
A- topsoil
B- subsoil
C- parent material.
podzolic soils - highly acidic soils that have lost most of their nutrients to leakage
as a result of high rainfall. It doesn’t preserve organic materials.
Nov, 28 2008
Chernozem soils - have lots of clay content and are alkaline soils with a thicker A
horizon than podzolic soils.
in tropical sites and soils there is poor site detection and preservation.
there are more archaeological sites in tall grass prairies b/c thats where the
animals that these cultures were hunting were found.
10000 years ago at the start of the holocene the ice age megatons died out.
neanderthals - found in europe, able to survive both the glacial and interglacial
periods. Have the largest brains of all humanoids which may have resulted in a
very high metabolism. they also had larger nasal passages to warm the air they
inhaled more.
remote sensing allows for archaeological site prediction and detection.
GIS - allows for site analysis and connections
archaeology allows for the study of past human geographical things like city
planning and urban development.
archaeological sites must be examined and understood in a geographical
context.
The surrounding environment must be known and understood when examining
an archaeological site.
Dec, 1 2008
climate is weather statistics and is a very complex system
the challenge of global climate change is that humans have never lived in a time
when temperatures are as high as they are becoming.
without the natural greenhouse effect the surface temperature of the earth would
be -18 degrees
Ice cores have air bubbles trapped within them and scientists can measure the
concentration of CO2 in these bubbles and see how it correlates with climate at
those times.
scientists are unsure of how climate will change and what it will do.
climate changes slowly all the time. however, we are within one degree of the
warmest avg temp in 125,000 years
we are seeing the fastest rate of warming we have ever recorded.
CO2 levels fluctuate throughout the year as plants use up or release carbon into
the atmosphere.
Methane is a more potent greenhouse gas than CO2 and CFC’s are the worst.
if we stop producing CO2 today the temp will continue to increase for many years
because of positive feedback and the very long residue time of CO2
in the midwest soil moisture will decrease by 10% and there will be many more
cases of extreme weather.
Dec, 3 2008
effects of global warming
flooding of low level areas
spread of tropical diseases to new areas
change in forests systems (pine beetle)
change in international trade relationships - especially those pertaining to
food
more competition for water
more hurricanes and extreme weather occurrences - 2008 was a record
year for the number of hurricanes.
change in habitats (polar bears, corals, birds and many insects)
water vapour is a strong greenhouse gas - the negative feedback of potentially
more clouds could slow the warming down. Also plants could become more
water efficient as more CO2 is in the air and allow them to transpire less.
the average sea level for the last 100 years was 1.8mm/year but during the last
15 years has increased to 3.1mm/year.
the oceans have warmed about half a degree and this is currently the main
reason of sea level raise as the water expands as it warms.
The Maldives will be the first nation to be completely submerged by sea level
rise.
in the past 5 years CO2 has accounted for 91% of the enhanced greenhouse
effect due to high atmospheric concentrations and its long lifespan.
we are at the highest levels of CO2 in the last 650,000 years.
Methane produced mainly by rice paddies and animal feces in has twenty times
the warming power of CO2 but a much shorter life span, only 9 years.
Nitrous Oxide N2O is a long living gas (150 years) that has 200 times the
warming power of CO2.
70% of N2O is produced naturally by microbes in soils and water and the other
30% is produced by the combustion of fossil fuels and fertilizer production
CFC’s - the strongest of greenhouse gasses as it is 10,000 times more powerful
than CO2 its lifespan is 65-130 years. Due to the fact that it reacts with and
breaks down Ozone it use is now extremely restricted.
Ozone O3 - absorbs deadly UV rays and reemits them as safe long wave
radiation.