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The Geosphere
The Geosphere
The Earth as a System
The Earth is a system of 4 interacting components. Consists of:
- Geosphere - Hydrosphere- Atmosphere - Biosphere
The GeosphereComposition
• The solid part of the Earth (rocks, minerals, soil, etc.)– Most of the geosphere is below the surface
What is it?
Lithosphere Cool, rigid layer that includes the crust; divided into plates
Asthenosphere Flexible layer of the mantle that flows slowly, allowing plates above it to move
Outer Core Liquid nickel and iron
Inner Core Solid nickel and iron
• Look at the world map. Does anything look like it could fit together like a puzzle?
The GeospherePlate Tectonics
Pangaea – Wegener’s idea that all of Earth’s continents were joined into one giant landmass 200 million years ago.
The GeospherePlate Tectonics
• The tectonic plates ride atop the asthenosphere, moving in different directions
Boundary Movement Result
Convergent 2 plates move together
Mountains, volcanoes, earthquakes
Divergent
Transform
Convergent Plate Boundaries
Continental-continental
Oceanic-continentalOceanic- oceanic
The GeospherePlate Tectonics
• The tectonic plates ride atop the asthenosphere, moving in different directions
Boundary Movement Result
Convergent 2 plates move together
Mountains, volcanoes, earthquakes
Divergent 2 plates move apart
Ocean ridges (volcanic), rift valleys, earthquakes
Transform
Divergent Plate Boundaries
Mid-ocean ridge
Rift Valley
The GeospherePlate Tectonics
• The tectonic plates ride atop the asthenosphere, moving in different directions
Boundary Movement Result
Convergent 2 plates move together
Mountains, volcanoes, earthquakes
Divergent 2 plates move apart
Ocean ridges (volcanic), rift valleys, earthquakes
Transform 2 plates slide past each other
Faults, earthquakes
Transform Plate Boundaries
The GeospherePlate Tectonics
Global Earthquake Distribution Global Volcano Distribution
The GeosphereEarthquakes Volcanic Eruptions
How does it happen?
Earth’s crust slips along a fault (crack in the crust)
Local Effects
Destruction, injuries, death
Global Effects
Tsunamis
Which of these geologic hazards poses the greatest threat to the environment? Why?
The GeosphereEarthquakes Volcanic Eruptions
How does it happen?
Earth’s crust slips along a fault (crack in
the crust)
Pressure of magma inside the volcano becomes so great that it blows open the solid surface.
Local Effects
Destruction, injuries, death
Destruction, injuries, death, mudflows,
*improved soil fertility
Global Effects
Tsunamis Ash clouds from major eruptions can
block sunlight & change drop the
average global temp.
The GeosphereErosion
• Rocks on the surface are changed by wind, running water, and weather.
• Erosion is the removal and transport of weathered surface materials.
• Over long periods of time, erosion can wear away entire mountains and produce spectacular landforms.
How is the land in this picture being used?
The Land
How We Use Land
Urban land = land covered mostly with buildings & roads and containing 2500 or more people.
Rural land = land containing few people & large areas of open space.
Think-Pair-ShareHow are each type of land cover important to
people?
The Urban-Rural ConnectionThink About It… Are people dependent on the
resources produced in rural areas?Ecosystem services – resources produced by natural
& artificial ecosystems
Urban Land Use
• Urbanization = the movement of people from rural areas to cities.
• People move to the cities for jobs.
Urbanization
Pros Cons
Urban Crisis
When urban areas grow too quickly, a crisis can occur.
Overwhelmed infrastructure (roads, sewers, railroads, bridges, firefighters/police, schools, libraries, hospitals, water mains, & power lines)
Traffic jamsSubstandard housingPolluted air & water
Urban Sprawl• Urban sprawl = rapid expansion of a city into
the countryside around the city.– Results from suburban building
• housing & commercial
Suburban development around Maui, HI
Development of Marginal Lands• Some suburbs have been built on land that
is not well suited to support buildings.
• This land is prone to landslides because it is unstable– Ex: Los Angeles, Mexico City
Urban Environmental Condition
Heat Islands – increased temperature in a cityWhy? - roads & buildings absorb more heat than vegetationEffects? – local weather patterns change, more rainfall in cities
Pollution of air, water, & land
Urban Planning• Land-use planning is essential for pleasant
urban living experiences. • Ex:
– Transportation in cities involves mass transit systems (buses, trains)
• Mass transit saves energy, reduces traffic, lowers air pollution, & limits the loss of land to roads & parking lots
– Open space is set aside in urban areas for recreational enjoyment (parks, gardens, bike paths, hiking trails)
• Open spaces absorb CO2, produce oxygen, filter pollutants, lower temperatures, absorb rainwater
Land Management & ConservationLand Type What is it? How is it used by
people?What are the
problems/threats to this land?
How can it be maintained / protected?
Farm landLAND USED FOR
CROPS AND FRUITS
FOOD URBAN DEVELOPMENT
FARMLAND PROTECTION
PROGRAM
Range landLAND THAT SUPPORTS
VEGETATION (GRASSES)
GRAZING LIVESTOCK
OVERGRAZING PUBLIC RANGELANDS
IMPROVEMENT ACT
Forest landLAND THAT SUPPORTS
TREES
WOOD, LUMBER,
PAPER, ETC.
DEFORESTATION (CLEARING WITHOUT
REPLACING)
REFORESTATION
Parks & Preserves
LAND PROTECTED
AGAINST DEVELOPMENT
RECREATION, WILDLIFE REFUGE,
PROTECTING ENDANGERED
SPECIES
INCREASED DEVELOPMENT,
VISITOR DESTRUCTION &
LITTERING
US WILDERNESS
ACT – PROTECTS
FROM EXPLOITATION
Designing A Community• You are a land-use planner. Design a model
community that is to be home for 1000 people. Name your community & tell us where in the world you are located.– Sketch your plans for the following:
• Housing• Commercial• Transportation routes• Open spaces• Community services (electricity, water, trash
collection, police & fire protection, schools, hospitals, etc.)
• Where will resources come from?
