Download Geology Test Study Guide Answers

Geology Unit Test Study Guide
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Layers of the Earth-(Chapter 7)
1. Know facts such as composition, state of matter, and location of each layer of the earth
including the lithosphere, asthenosphere, and mesosphere.
From the surface of the Earth to the middle, the main layers are the crust, mantle, outer core
and inner core. The crust is made up of silicon, aluminum and oxygen. Its state of matter is
solid. It is the outer layer.
The mantle is located between the crust and the outer core. It is made up of silicon,
magnesium, aluminum. It is part solid, and part magma.
The outer core is located between the mantle and the inner core. It is made up of iron and
nickel. It is liquid.
The inner core is the innermost layer. It is a solid ball of iron.
The lithosphere consists of the crust and the rigid upper part of the mantle. It is a solid.
The asthenosphere is the soft layer of the mantle on which the tectonic plates move. It is
located between the lithosphere and the mesosphere.
The mesosphere is the strong, lower part of the mantle between the asthenosphere and the
outer core.
2. How does density, temperature, and pressure change as you move from the lithosphere to the
inner core? The density increases, the temperature gets hotter and the pressure greater as
you move from the lithosphere to the core.
3. Know what convection currents are deep inside the earth and how it relates to plate movement.
The material in the mantle heats up and rises. As it cools it sinks, creating a circular motion.
This circular motion causes plate movement.
4. How do scientists learn about the interior of the earth?
Scientists study seismic waves generated by earthquakes.
Plate Tectonics- (Chapter 7 )
1. Who is Alfred Wegener and what evidence did he have to support his theory of continental
drift? He is a German science who came up with the theory of continental drift. Pieces of
evidence he had were dinosaur fossils found on separate continents, plant life found on
continents and places with different climate zones, discovery of the mid ocean ridge and the
age of the rocks found on the sea floor.
2. What is Pangea, and what happened to this landmass after it broke apart?
Pangaea drifted over millions of years to the present position it is located today.
3. What is sea floor spreading, where does it occur, and what evidence supports this concept?
Sea floor spreading happens at the mid ocean ridge. Magma from the mantle pushes through
the sea floor causes the plates to diverge and spread apart. The evidence to support sea floor
spreading is the age of the rocks. The further away you are from the mid ocean ridge the older
the rock.
4. How do tectonics plates move and what geologic events occur at convergent, divergent, and
transform boundaries?
Tectonic plates move because of convection currents in the mantle.
Convergent boundary – plates come together and collide. Mountains form, subduction can
also occur. If ocean-ocean plates meet, you can have a valley or ocean trench.
Divergent boundaries- when plates move away from one another – sea floor spreading
happen, mid-ocean ridges can form.
Transform boundaries- plates slide up and down against each other- earthquakes happen
Volcanic Mountains- Forms at subduction zones. Ex: Mount St. Helen
Earthquakes- Chapter 8
1. What is an earthquake and how do plates and boundaries relate to this event?
An earthquake is the shaking of the earth caused by the sudden release of energy from rocks
under tectonic stress. Most earthquakes are associated with rock movements along faults
below the surface of the earth. Earthquakes happen near or at plate boundaries.
2. What tool and scale is used to measure earthquakes? How are p and s waves similar and
different? The tool used to measure earthquakes is a seismograph. The scale used to measure
earthquakes is the Richter Scale. P-waves and S-waves are both waves that move through
Earth’s interior. P-waves are pressure waves. They are the fastest seismic waves. S-waves are
shear waves. They are the second-fastest seismic waves. Unlike P-waves, S-waves cannot
travel through parts of the Earth that are completely liquid.
Volcanoes- Chapter 9
2.Explain the difference between explosive and non explosive eruptions

non-explosive - produce relatively calm flows of lava. Although it may be calm, huge
amounts lava may flow.

explosive - are more rare, but incredibly destructive. Instead of producing lava flows,
explosive eruptions cause molten rock to be blown into tiny particles that harden in
the air. The dust-sized particles, called ash, can reach the upper atmosphere and can
circle the Earth for years. Larger pieces of debris fall closer to the volcano. An
explosive eruption can also blast millions of tons of lava and rock from a volcano. In a
matter of seconds, an explosive eruption can demolish an entire mountainside.
1. How was the Ring of Fire formed?
The majority of volcanoes are located in the Pacific Ocean in an area called the Ring of Fire.
The Ring of Fire is the result of plate tectonics. Much of the volcanic activity occurs along
subduction zones which are convergent plate boundaries where two tectonic plates come
together. The heavier plate is shoved (or subducted) under the other plate. When this
happens, melting of the plates produces magma. The magma rises up through the overlying
plate, erupting to the surface as a volcano.
4What is the difference between an active and dormant volcano
Active vs. dormant volcano.
Active volcanoes are volcanoes that erupt fairly regularly.
Dormant volcanoes are volcanoes that have not erupted in a very long time (but could).