Physical Geology – Spring 2006
Review Sheet – Midterm I
Chapter 1
 What are the five spheres within the Earth system?
 How is Earth system science different from traditional sciences such as chemistry or
physics?
 What are the main categories of materials that make up the Earth?
 How do the following classifications of materials differ in terms of composition and
density?
 silicic (felsic), intermediate, mafic, ultramafic
 Know the chemical properties of the inner core, outer core, mantle, and crust.
 Contrast the continental and oceanic crust in terms of thickness and composition.
 What is the difference between the lithosphere and the asthenosphere? How are the criteria
for defining the lithosphere and asthenosphere different from the criteria used to recognize
the crust, mantle, and core?
Key Terms:
seismic discontinuity
seismology
Moho discontinuity
asthenosphere
lithosphere
continental crust
oceanic crust
mantle
inner core
outer core
earth system science
silicic
felsic
intermediate
mafic
ultramafic
Chapter 2
 What lines of evidence did Wegener use to support his continental drift hypothesis? Why
wasn’t his hypothesis widely accepted by the scientific community?
 What is apparent polar wander? How is it used to further support ‘drifting continents’?
 What lines of evidence support the seafloor spreading hypothesis? How did this hypothesis
improve upon the continental drift hypothesis?
 How does the density of continental and oceanic lithosphere differ? Why is this important
for plate tectonics?
 How do lithospheric plates move?
 For each of the 3 plate boundary types (convergent, divergent, transform) know:
o the type of motion involved
o what processes are involved (e.g., subduction, extension, transform faulting,
volcanism, earthquakes, etc)
o what surface features are associated with the plate boundary
o an example location
 What is a hot spot? Are hot spots associated with plate boundaries? Why or why not?
 What is the source of magma in a hot spot?
 What can hot spots tell us about the history of plate motion?
 What is an example location of a hot spot?
 What is continental rifting? Where is it occurring today?
 What 2 mechanisms are proposed to drive plate motion?
Key Terms:
Pangaea
glacial striation
paleomagnetism
magnetic reversal
lithospheric plate
plate boundary
subduction zone
island arc
MOR
triple junction
Wadati-Benioff zone
Chapter 10
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What are the 4 main time units used to divide the geologic time scale?
What are the 4 main Eons?
What 3 Eras make up th ePhanerozoic Eon?
We looked at 7 principles used for relative age dating. Know these 7 principles and how to
apply them. (Principles of…..uniformitarianism, superposition, original horizontality,
original continuity, cross-cutting relationships, inclusions, fossil succession)
What is represented by an unconformity?
What method is used for numerical age dating?
Why can’t Carbon-14 be used to date things older than 70,000 years?
Key Terms:
angular unconformity
nonconformity
disconformity
isotope
radioactive isotope
parent and daughter isotope
half-life
Chapter 3
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You should know the definition of a mineral.
What properties are used to identify minerals?
What are 3 ways that a mineral can form?
What are the 7 mineral classes? What defines each group?
Which is the most commonly occurring class of minerals on the Earth?
What are the 5 groups of silicate minerals? What are the properties of each group?
Key Terms:
crystal
polymorph
silicon-oxygen tetrahedron
crystal lattice
glass
Z
X
Y
Oldest
Youngest
E,G,L,C,H,Y,M,D,J,A,X,N,K,B,Z, F