Solid Earth Study Guide Key
Please complete the following study guide in preparation for your test on the
Solid Earth. This review is designed to help your understanding of the concepts.
These questions on the study guide will not appear on your test.
Earth History
Asteroid Impact Theory v. Gradual Extinction Theory.
** Review your Guided Highlighted Read. This reading passage will be on your test and you will be asked
DIFFERENT questions to assess your understanding of the reading.
Index Fossils
1) Based on the drawing above, which fossil is considered an index fossil, A, B, C or D? A
2) List the four requirements for determining if a fossil is an index fossil.
1)
2)
3)
4)
Clearly distinguishable from other fossils.
Found in rocks scattered over a large region.
Lived for a short period of geologic time.
Occur in fairly large numbers.
Plate tectonic Theory
1) Explain how marine fossils can be found at the top of a mountain or in the middle of a
continent.
Due to plate tectonic movement, marine environments have shifted to different parts of the globe.
Areas once covered by oceans may not be today. Over time, plates that were once in a marine
environment, might be uplifted to form mountains.
Relative Age
2) Refer to the illustration above and put the rock layers in order from youngest to oldest.
E, A, D, C, B,
Absolute Age
1) Define half-life. The time it takes for half of the amount of a radioactive parent isotope to decay
into the daughter isotope.
Refer to the chart above for the following question.
1) A sample originally contained 100 g of C-14. The sample now contains 25 g of C-14. How old is
the sample?
a) What information is necessary to answer the following problem? The half-life of C-14
b) Solve the problem below. Show your work.
5730 x 2 = 11,460 years
Early formation of Earth
1)
Fill in the blanks below to describe the three major changes that occur as a solar nebula shrinks
in size and begins to form planets. The figure below can be found in your textbooks on p. 750.
**BEWARE** Do not copy the descriptions that are found below the pictures in your text. Use
the figure for a better look at the pictures only.
1- The solar nebula gets hotter
2- The rate of rotation of the solar nebula increases
3- The solar nebula flattens into a disk.
2) Describe the accretion phase of the early solar system.
Planetesimals formed by particles colliding due to gravity and sticking together. Planetesimals join
together through this process to form protoplanets. Gravity then caused planetesimals to collide with
protoplanets adding mass, creating planets.
3) What provided the Earth with fresh water during its formation?
Early on, icy bodies, such as comets, collided with Earth. Water from these bodies then became part of
Earth's atmosphere. As Earth cooled, water vapor condensed to form rain. This liquid water collected on
the surface to provide the first water on Earth.
4) What method or process is used to determine the age of the solar system?
Scientists use radiometric dating to determine the age of the solar system.
5) Which would scientists use to determine the age of the solar system, Earth rocks or meteorites?
Why?
Scientists use meteorites to determine the age of the solar system. Due to the processes of the
rock cycle, the age of the solar system cannot accurately be determined by using even the oldest
Earth rocks.
6) What role did gravity play in the formation of the solar system?
Energy from collisions and pressure from gravity caused the center of the solar nebula to become hotter
and denser. This caused the beginning of hydrogen fusion, forming our sun. The remaining material was
acted upon by gravity and collided forming the planets and moons in the solar system.
Rock Cycle
1) Review the diagram below and describe how subduction of plates contribute to the rock cycle.
FIGURE A
Answer: Heat and pressure at the subduction zones cause existing rocks to metamorphose into other
rocks.
2) For the following rock types, describe how the rock is formed and at what type of boundary, if
any, the formation would occur.
a) Igneous- formed at divergent and convergent boundaries; formed from the cooling of lava
or magma.
b) Sedimentary- Sediments form through weathering and erosion. Those sediments are
deposited, then compacted and cemented to form sedimentary rock. Although not formed
at a specific boundary, plate tectonics can affect sedimentary rock through uplifting and
formation of mountains.
c) Metamorphic- formed at convergent boundaries; formed deep within the Earth’s crust due
to heat, pressure and chemical processes acting on existing rock.
Plate tectonics
1) Describe the difference between oceanic and continental plates.
Oceanic- highly dense, thinner, composed of rocks rich in iron and magnesium
Continental- low density, thicker, composed of rocks rich in silica.
Figure A
REFER TO FIGURE A (above) for the questions 2-4.
2) What type of boundary(ies) is(are) shown?
Convergent and divergent boundaries
3) What type of crustal collisions are happening at each boundary? (Ex. Continental-continental,
oceanic-oceanic, oceanic-continental)
No collision at divergent boundary, plates are pulling apart from one another.
The figure shows oceanic-continental collision at the convergent boundary.
4) Which plate is subducting? Why?
The oceanic plate is subducting because it is denser than the continental plate.
5) List the features on Earth that form from each of the following collisions.
a) Oceanic-oceanic
a. Deep ocean trench
b. Island arcs
b) Oceanic-continental
a. Deep ocean trench
b. Volcanic mountains
c) Continental-continental
a. mountains
6) Use the formula rate = distance ÷ time to solve the following problem:
The Pacific plate on which the city of Los Angeles is located is moving northwest as the plate on
which San Francisco is located is moving southeast. The two cities are moving closer to one another
at a rate of about 0.00005 km per year. The cities are now a distance of 611 km apart. How many
years from now will the cities meet? 611 km ÷ 0.00005 km/yr = 12,220,000 years.
7)
Using the figure below (found on p. 272 of your textbook), describe the cause of plate tectonic
movement. Mantle material moves due to convection currents. The overlying plates move
along with the material (riding on the mantle).
Interior of the Earth
1) Using the diagram above, explain the presence of P-wave and S-wave shadow zones.
P-wave shadow zones are created because P-waves change speed and direction as they travel through
different materials. P-waves can travel through both solids and liquids.
S-wave shadow zones are created because S-waves can only travel through solids.
Earthquakes and Volcanoes
1) Describe the chemical composition of mafic and felsic magma and how this composition affects
the explosivity of volcanoes.
Mafic magma is rich in iron and magnesium; generally dark in color; low viscosity so gases do not
become trapped, thereby producing quiet eruptions
Felsic magma is rich in feldspar and silica; generally light in color; high viscosity which traps gases,
increasing pressure inside a volcano and producing explosive eruptions.
2) Explain the difference between the Richter scale and the Modified Mercalli Scale. (What do they
measure and what do those measurements mean?)
Richter scale measures the magnitude of an earthquake. The magnitude is the amount of ground
motion caused by an earthquake.
Modified Mercalli Scale measures the intensity of an earthquake. Intensity is the amount of damage
caused by an earthquake.
3) List the 3 types of plate boundaries and fill in the rest of the table with “yes” or “no”.
Type of boundary
Can produce earthquakes?
Convergent
Divergent
Transform
Yes
Yes
Yes
Can produce volcanic
activity?
Yes
Yes
no