The Geosphere
The Earth as a System
The Earth is a system of 4 interacting components.
Consists of:
- Geosphere
- Atmosphere
- Hydrosphere
- Biosphere
The Geosphere
Composition
• 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
Outer Core
Flexible layer of the mantle that
flows slowly, allowing plates above
it to move
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 Geosphere
Plate Tectonics
Pangaea – Wegener’s idea
that all of Earth’s
continents were joined
into one giant landmass
200 million years ago.
The Geosphere
Plate Tectonics
• The tectonic plates ride atop the asthenosphere,
moving in different directions
Boundary
Movement
Convergent 2 plates move
together
Divergent
Transform
Result
Mountains, volcanoes,
earthquakes
Convergent Plate Boundaries
Continental-continental
Oceanic- oceanic
Oceanic-continental
The Geosphere
Plate Tectonics
• The tectonic plates ride atop the asthenosphere,
moving in different directions
Boundary
Movement
Convergent 2 plates move
together
Divergent
2 plates move
apart
Transform
Result
Mountains, volcanoes,
earthquakes
Ocean ridges
(volcanic), rift valleys,
earthquakes
Divergent Plate Boundaries
 Mid-ocean ridge
Rift Valley 
The Geosphere
Plate Tectonics
• The tectonic plates ride atop the asthenosphere,
moving in different directions
Boundary
Movement
Convergent 2 plates move
together
Divergent
2 plates move
apart
Transform
2 plates slide
past each other
Result
Mountains, volcanoes,
earthquakes
Ocean ridges
(volcanic), rift valleys,
earthquakes
Faults, earthquakes
Transform Plate Boundaries
The Geosphere
Plate Tectonics
Global Earthquake Distribution
Global Volcano Distribution
The Geosphere
Earthquakes
Volcanic Eruptions
How does it Earth’s crust slips
happen?
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 Geosphere
Earthquakes
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 Geosphere
Erosion
• 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.
The Land
How is the land
in this picture
being used?
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-Share
How are each type of land cover important to
people?
The Urban-Rural Connection
Think 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 jams
Substandard housing
Polluted 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 city
Why? - roads & buildings absorb more heat than
vegetation
Effects? – 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 & Conservation
Land Type
Farm land
Range land
Forest land
Parks &
Preserves
What is it?
How is it used by
people?
What are the
problems/threats to this
land?
How can it be
maintained / protected?
LAND USED FOR
CROPS AND
FRUITS
FOOD
URBAN
DEVELOPMENT
FARMLAND
PROTECTION
PROGRAM
LAND THAT
SUPPORTS
VEGETATION
(GRASSES)
GRAZING
LIVESTOCK
OVERGRAZING
PUBLIC
RANGELANDS
IMPROVEMENT
ACT
LAND THAT
SUPPORTS
TREES
WOOD,
LUMBER,
PAPER, ETC.
LAND
PROTECTED
AGAINST
DEVELOPMENT
RECREATION,
WILDLIFE
REFUGE,
PROTECTING
ENDANGERED
SPECIES
DEFORESTATION
REFORESTATION
(CLEARING
WITHOUT
REPLACING)
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?