Transcript Dynamic Earth Processes

Integrated
Coordinated
Science
End of Year Review
Part 1:
Geology
Dynamic Earth Processes
Standard 3a: Students know features of the ocean
floor (magnetic patterns, age, and sea-floor
topography) provide evidence for plate tectonics.
The basalt (rock of the ocean basins) have
magnetic patterns (normal or reverse
polarity) due to the Earth’s polarity at the
time of the rocks creation.
The oceanic ridge is the site of seafloor spreading. New rock is formed in
the center of the ridge and the rock
becomes older as you move away from
the ridge.
The spreading sea floor pushes up
against the continental crust forming
subduction zones and moves the
continents (continental drift) as the sea
floor spreads.
Dynamic Earth Processes
Standard 3b: Students know the principal structures that form at the three
different kinds of plate boundaries.
1. Divergent plate boundaries: Two plates
move away form each other. As the plates
move apart the Earth’s crust becomes thinner
forming mid-ocean ridges (causing sea-floor
spreading), rift valleys (tearing land apart and
submarine volcanoes.
2. Convergent plate boundaries: Two
plates move towards each other. As the
plates crash together the form subduction
zones (in which the more dense oceanic
crust dives under the less dense continental
crust) at which volcanic arcs, ocean
trench, earthquakes and mountain ranges
occur.
3. Transform plate boundaries: Two plates
move laterally (Parallel slip) past each other.
This movement cause earthquakes along
such faults as the San Andreas Fault.
Dynamic Earth Process
Standard 3c: Students know how to explain the properties of rocks based on the
physical and chemical composition in which they formed, including plate tectonic
processes.
All rocks are composed of minerals..
1. Igneous rocks are formed when
molten magma or lava cools
2. Metamorphic rocks are formed by
subjecting any rock type to high
temperature and pressure changing
the original rock.
3. Sedimentary rocks are formed
when igneous and metamorphic
rocks are broken into sediment by
erosion followed by being compacted
and cementation together.
Slow cooling
large crystals
Fast cooling no
crystals
Crystals: When magma cools slowly it allows for the formation of larger crystals.
This process usually occurs inside the Earth.
When magma cools quickly crystals cannot form. This usually occurs on the Earth’s
surface.
Dynamic Earth Processes
Standard 3d: Students know why and how earthquakes occur and the scales used
to measure their intensity and magnitude.
Earthquakes occur along plate margins
where lithospheric plate move against
each other. The plates build up enough
energy to overcome frictional forces and
slip, causing an earthquake.
The magnitude of an earthquake is
measured by the Richter scale. The
Richter scale measure the amplitude of
the earthquake’s wave which is related
to the energy released.
The intensity of an earthquake is
measured by the Mercalli scale
based on how the shaking felt and
how much damage was done.
Dynamic Earth Processes
Standard 3e: Students know there are two kinds of volcanoes: one kind with
violent eruptions producing steep slopes and the other kind with voluminous lava
flows producing gentle slopes.
The violence of a volcanic eruption is
based on the viscosity (how thick the
liquid is) of the magma.
Temperature and chemical
composition (silica content) determine
the viscosity of the magma. High
temperature: low viscosity, high;
silica: high viscosity.
Cone shaped volcanoes are formed from
highly viscous magma and erupt
violently.
Shield volcanoes are formed from
magma with low viscosity and have
gentle slopes caused by the watery
magma flowing far from the vent.
Dynamic Earth Processes
Standard 3f: Students know the explanation for the location and properties of
volcanoes that are due to hot spots and the explanation for those that are due to
subduction.
Volcanoes form at
subduction zones as
melted rock rises to the
surface forming
volcanoes. These
volcanoes are
concentrated at plate
boundaries (edges of
continents) like the ring
of fire.
Volcanoes form at hot
spots as the continent
moves over a molten spot
in the mantle. They are
located in the middle of
plates (away form the
edges) like Yellowstone
and Hawaii.
End of Part 1:
Geology