Geology Reference
In-Depth Information
Review Questions
1. A fault on which the footwall block has moved up
relative to the hanging wall block is a _______ fault.
a. _____ normal;
b. _____ thrust;
c. _____ strike-slip;
d. _____ oblique-slip;
e. _____ reverse.
2. A time of mountain building during which deformation
occurs, accompanied by the emplacement of plutons,
metamorphism, and thickening of the crust is a/an
a. _____ terrane;
b. _____ monocline;
c. _____ orogeny;
d. _____ gravity anomaly;
e. _____ magnetic reversal.
3. According to the principle of isostasy,
a. _____ continental crust is denser than oceanic crust;
b. _____ anticlines and synclines are caused by
compression;
c. _____ the hanging wall block of a fault moves down
relative to the footwall block;
d. _____ the strike of an inclined rock layer is defi ned
by its volume;
e. _____ the continents are “fl oating” on the denser mantle.
4. A circular fold with all strata dipping toward the center
and the youngest exposed rock layers at the center is a/an
a. _____ joint;
b. _____ basin;
c. _____ horst;
d. _____ anticline;
e. _____ monocline.
5. Which one of the following statements is incorrect?
a. _____ Most orogenies occur at convergent plate
boundaries;
b. _____ Shear stress involves forces acting along the
same line, but in opposite directions;
c. _____ Joint are fractures along which no movement
has occurred parallel with the fracture;
d. _____ The dip of a rock formation is its inclination
from horizontal;
e. _____ Folds and faults are collectively known as
geologic structures.
6. A continent-continent collision was responsible for the
a. _____ Cascade Range;
b. _____ Basin and Range mountains;
c. _____ Andes Mountains;
d. _____ Himalaya Mountains;
e. _____ Sea of Japan Range.
7. Rocks characterized as ductile
a. _____ show a great amount of plastic strain;
b. _____ are the main rocks in terranes;
c. _____ are found along the crests of anticlines;
d. _____ fracture easily when in compression;
e. _____ are found on the hanging wall blocks of faults.
8. The line formed by the intersection of an inclined plane
with a horizontal plane is the defi nition of
a. _____ stress;
b. _____ brittle behavior;
c. _____ strike;
d. _____ uplift;
e. _____ jointing.
9. The fault in Figure 10.16e shows both _________ and
_________ faulting.
a. _____ thrust/reverse;
b. _____ normal/left-lateral strike-slip;
c. _____ left-lateral strike-slip/monocline;
d. _____ elastic/dome;
e. _____ overturned/recumbent.
10. A fold in which one limb has been rotated more than
90° from its original position is said to be
a. _____ left-lateral;
b. _____ oblique;
c. _____ synclinal;
d. _____ overturned;
e. _____ inverted.
11. What are the similarities and differences between a
basin and a syncline?
12. Describe how time, rock type, pressure, and tempera-
ture infl uence rock deformation.
13. Suppose that rocks were displaced 200 km along a
strike-slip fault during a period of 5 million years.
What was the average rate of movement per year? Is the
average likely to represent the actual rate of displace-
ment on this fault? Explain.
14. Draw a surface view of a plunging syncline and an
adjacent plunging anticline. Show strike and dip sym-
bols and indicate on your diagram which rock layer is
oldest and which is youngest.
15. Is there any connection between the principle of isos-
tasy and mountain building? If so, what?
16. How would you explain stress and strain to someone
unfamiliar with the concepts?
17. What is meant by the elastic limit of rocks, and what
happens when rocks are strained beyond their elastic
limit?
18. How does a dip-slip fault differ from a strike-slip fault?
19. What is the concept of isostatic rebound? Give an
example of how it may take place.
20. What kinds of evidence would indicate that mountain
building once took place in an area where mountains
are no longer present?
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