A view of Earth

1
A view of Earth

• Earth is a planet that is small and
  self-contained
• Earths four spheres
• Hydrosphere
• Atmosphere
• Biosphere
• Solid Earth

2
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3
Earth as a system

• dynamic planet with many interacting parts or
  spheres
• Earth System Science
• Aims to study Earth as a system composed of
  numerous interacting parts or subsystems
• Employs an interdisciplinary approach to solve
  global environmental problems

4
Earth as a system

• What is a system
• Any size group of interacting parts that form a
  complex whole
• Open vs. closed systems
• Feedback mechanisms
• Negative feedback maintains the status quo
• Positive feedback enhances or drives changes

5
Earth as a system

• The Earth system is powered by the Sun that
  drives external processes in the
• Atmosphere
• Hydrosphere
• At Earths surface
• The Earth system is also powered by Earths
  interior

6
Early evolution of Earth

• Origin of planet Earth
• Most researchers believe that Earth and the other
  planets formed at essentially the same time
• Nebular hypothesis
• Rotating cloud called the solar nebula
• Composed of hydrogen and helium
• Nebula began to contract about 5 billion years
  ago

7
Early evolution of Earth

• Origin of planet Earth
• Nebular hypothesis
• Assumes a flat, disk shape with the protosun
  (pre-Sun) at the center
• Inner planets begin to form from metallic and
  rocky substances
• Larger outer planets began forming from fragments
  of ices (H2O, CO2, and others)

8
Early evolution of Earth

• Formation of Earths layered structure
• Metals sank to the center
• Molten rock rose to produce a primitive crust
• Chemical segregation established the three basic
  divisions of Earths interior
• Primitive atmosphere evolved from gases in
  Earths interior

9
Earths internal structure

• Layers defined by composition
• Crust
• Mantle
• Core
• Layers defined by physical properties
• Lithosphere
• Asthenosphere
• Mesosphere
• Inner and Outer Core

10
The Earths Crust (not much in common)

• Continental Crust

• Oceanic Crust

• 25 40 miles Rockies Himalayas
• Many rock types
• 2.7g/cm3 dense
• 4 billion years old

• 5 mi thick
• Mostly basalt, a dark igneous rock
• 3.0g/cm3 dense (denser than the continental
  crust)
• 180 million years old

11
Earths layered structure
Figure 1.14
12
The face of Earth

• Earths surface
• Continents
• Oceans
• Continents
• Mountain belts
• Most prominent feature of continents
• The stable interior
• Also called a craton composed of shields and
  stable platforms

13
Shields interior of continents. Ancient
undisturbed regions
14
The face of Earth

• Ocean basins
• Continental margins
• Includes the continental shelf, continental
  slope, and the continental rise
• Deep-ocean basins
• Abyssal plains
• Oceanic trenches
• Seamounts

15
Ocean topography
16
The face of Earth

• Ocean basins
• Oceanic ridge system
• Most prominent topographic feature on Earth
• Composed of igneous rock that has been fractured
  and uplifted

17
Rocks and the rock cycle

• Basic rock types
• Igneous rocks
• Cooling and solidification of magma (molten rock)
  
• Examples include granite and basalt
• Sedimentary rocks
• Accumulate in layers at Earths surface
• Sediments are derived from weathering of
  preexisting rocks

18
The rock cycle
Figure 1.21
19
Plate Tectonics

• Chapter 2

20
But First!!! A quick quiz (10pts)

• Number a sheet of paper 1-10
• 1. What does geo mean?
• 2. The field of geology covers the main topics of
  physical geology, human interactions with it, and
  ______geology.
• 3. The physical, chemical and biological laws
  that operate today also operated in the geologic
  past is the definition for___________________
• 4. How old is our planet earth according to
  radioactive dating?
• 5. If I dig a hole in my backyard, the youngest
  rocks are likely to be on the top. This is based
  on the Law of ______________.
• 6. Once a hypothesis has been tested, it can be
  called a _______________.
• 7. A hurricane is an example of an (choose one)
  open system, closed system.
• 8. A warmer atmosphere will increase evaporation,
  adding more water vapor to the atmosphere which
  is a green house gas that warms the atmosphere
  even more. This is an example of a
  ______________feedback loop.
• 9. What are the three major catagories of rocks?
• 10. The biosphere contains all _______________on
  earth.

21
Continental Drift
_________ proposed the theory that the crustal
plates are moving over the mantle. This was
supported by fossil and rock type evidence also
matching of coastline shapes.
Wegener
22
Convection Currents
The force responsible for plate movement is
__________.
23
Plate Boundaries

• The following two slides show maps of the current
  major plate boundaries and their relative
  motions.
• You should be able to describe various landforms
  created by different plate movements.

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Plate Boundaries

• Divergent Boundary moving _____
• Convergent Boundary moving ________
• Transform Fault Boundary moving
  ________________________

apart
together
sideways past each other
27
Divergent boundary of two continental
plates. Creates a __________. Example
_____________
rift valley
East African Rift
28
Convergent boundary of two oceanic
plates. Creates an ________ and a _____.
Example _____
island arc
trench
Japan
29
Convergent boundary of an oceanic plate and a
continental plate. Forms a _______ mountain range
and a ______. Examples _______ or _______ Mts
volcanic
trench
Andes
Cascades
30
Convergent boundary of two continental plates.
Forms a ______ mountain range. Examples
___________, Alps, ______________
Himalayas
folded
Appalachians
31
Transform-fault boundary where the North American
and Pacific plates are moving ____ each
other. Example ________________ in California
past
San Andreas Fault
32
Plate Boundaries Review

• Places where plates move apart are called
  _____________ boundaries.
• When continental plates diverge a ___________ is
  formed.
• When two oceanic plates converge what is created?
  _________________
• The Appalachians formed mainly from continental
  plate collisions and therefore are a __________
  mountain range.
• The force moving the plates is ____________ .

divergent
rift valley
an island arc and a trench
folded
Convection currents
33
A view of Earth

• Earth is a planet that is small and
  self-contained
• Earths four spheres
• Hydrosphere
• Atmosphere
• Biosphere
• Solid Earth

34
Earth as a system

• Earth is a dynamic planet with many interacting
  parts or spheres
• Earth System Science
• Aims to study Earth as a system composed of
  numerous interacting parts or subsystems
• Employs an interdisciplinary approach to solve
  global environmental problems

35
Earth as a system

• What is a system
• Any size group of interacting parts that form a
  complex whole
• Open vs. closed systems
• Feedback mechanisms
• Negative feedback maintains the status quo
• Positive feedback enhances or drives changes

36
Earth as a system

• The Earth system is powered by the Sun that
  drives external processes in the
• Atmosphere
• Hydrosphere
• At Earths surface
• The Earth system is also powered by Earths
  interior

37
Early evolution of Earth

• Origin of planet Earth
• Most researchers believe that Earth and the other
  planets formed at essentially the same time
• Nebular hypothesis
• Rotating cloud called the solar nebula
• Composed of hydrogen and helium
• Nebula began to contract about 5 billion years
  ago

38
Early evolution of Earth

• Origin of planet Earth
• Nebular hypothesis
• Assumes a flat, disk shape with the protosun
  (pre-Sun) at the center
• Inner planets begin to form from metallic and
  rocky substances
• Larger outer planets began forming from fragments
  of ices (H2O, CO2, and others)

39
Early evolution of Earth

• Formation of Earths layered structure
• Metals sank to the center
• Molten rock rose to produce a primitive crust
• Chemical segregation established the three basic
  divisions of Earths interior
• Primitive atmosphere evolved from gases in
  Earths interior

40
Earths internal structure

• Layers defined by composition
• Crust
• Mantle
• Core
• Layers defined by physical properties
• Lithosphere
• Asthenosphere
• Mesosphere
• Inner and Outer Core

41
Earths layered structure
Figure 1.14
42
The face of Earth

• Earths surface
• Continents
• Oceans
• Continents
• Mountain belts
• Most prominent feature of continents
• The stable interior
• Also called a craton composed of shields and
  stable platforms

43
The face of Earth

• Ocean basins
• Continental margins
• Includes the continental shelf, continental
  slope, and the continental rise
• Deep-ocean basins
• Abyssal plains
• Oceanic trenches
• Seamounts

44
The face of Earth

• Ocean basins
• Oceanic ridge system
• Most prominent topographic feature on Earth
• Composed of igneous rock that has been fractured
  and uplifted

45
Rocks and the rock cycle

• Basic rock types
• Igneous rocks
• Cooling and solidification of magma (molten rock)
  
• Examples include granite and basalt
• Sedimentary rocks
• Accumulate in layers at Earths surface
• Sediments are derived from weathering of
  preexisting rocks

46
Rocks and the rock cycle

• Basic rock types
• Sedimentary rocks
• Examples include sandstone and limestone
• Metamorphic rocks
• Formed by changing preexisting igneous,
  sedimentary or other metamorphic rocks
• Driving forces are increased heat and pressure
• Examples include gneiss and marble

47
Rocks and the rock cycle

• The Rock Cycle One of Earths subsystems
• The loop that involves the processes by which one
  rock changes to another
• Illustrates the various processes and paths as
  earth materials change both on the surface and
  inside the Earth

48
The rock cycle
Figure 1.21