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The Dynamic Earth
Introduction
• The Earth is an integrated system
containing the geosphere, atmosphere,
hydrosphere, and biosphere
Geosphere
• The solid part of the earth; Earth’s surface;
contains rock, minerals, and sediments
• Broken up into 3 categories: the crust, the
mantle, and the core
• However, there are layers within these 3 layers:
(see next slide)…
The moving Earth
Destruction is surface weathering, erosion, etc.
Construction is tectonics = Earthquakes, volcanoes,
mountain building in general
Theory of continental drift
Parts of the Earth's crust slowly drift atop a liquid core.
This theory is supported by fossil records.
Continental Drift Theory
• Wegener hypothesized that there was a gigantic
supercontinent 200 million years ago, which he named
Pangaea, meaning "All-earth".
• Pangaea started to break up into two smaller
supercontinents, called Laurasia and Gondwanaland,
during the Jurassic period. By the end of the
Cretaceous period, the continents were separating
into land masses that look like our modern-day
continents.
• VIDEO
Plate Tectonics
Theory of plate tectonics
Explains the movement of the Earth's plates and also
explains the cause of earthquakes, volcanoes,
mountains, etc.
There appear to be 13 major plates that cover the globe.
Plate Movement/ Boundaries
At the boundaries of the plates, various deformations
occur as the plates interact:
Divergent Plate Movement: PLATES PULL APART!
(Example: Seafloor Spreading) Seafloor spreading is
the movement of two oceanic plates away from each
other,
Plate Movement/ Boundaries
Convergent Plate Movement: PLATES COLLIDE!
When two plates collide, some crust is destroyed in the impact
and the plates become smaller.
Oceanic Plate and Continental Plate - When a thin, dense
oceanic plate collides with a relatively light, thick continental
plate, the oceanic plate is forced under : SUBDUCTION!
Two Oceanic Plates – One is pushed under the other and
magma from the mantle rises, forming volcanoes in the vicinity.
Two Continental Plates - Mountain ranges form!
Plate Movement/ Boundaries
Lateral Slipping Plate Movement:
When two plates move sideways against each other,
there is a tremendous amount of friction which makes
the movement jerky. The plates slip, then stick as the
friction and pressure build up to incredible levels:
What can this cause?
EARTHQUAKE!
Erosion
Erosion is the process that breaks down things
around us, destroying and creating landforms.
What causes erosion?
Natural:
Wind, water, etc.
Human-caused:
Chemicals, destruction, etc.