1. GEOP503 Solid-Earth Geophysics
Chapter Exam Chapter 9; Oceanic Lithosphere: ridges, transforms,
trenches and oceanic islands
March 21, 2008
1. Where is the deepest known spot
in the world oceans found? How
deep is it?
2. The Earth is about 4.6 billion years
old. Referring to Plate 2 at your
text book (Fowler, 2005), why do
you think that the oldest ocean
floor is only about 200 million
years old?
3. What is the water depth above 16
myr old ocean floor?
4. Look carefully at Plate 8 at your
text book (Fowler, 2005), describe
the physical relationship between
the Mid-Atlantic Ridge, the Mid-
Indian Ocean Ridge, the Pacific
Antarctic Ridge, and Eastern Pacific
Ridge. What do they have in
common?
5. Look carefully at Plate 8 in your
textbook (Fowler,2005). Compare
and contrast the type of
continental margin found along the
west coast of North America,
versus the type of continental
margin found along the east coast
of North America. Explain your
reasoning.
6. Referring to Figure 9.8 at your
textbook (Fowler,2005)., how do

2. you explain your reasoning for
principal ophiolite belts of the
world?
7. Referring to Plate 19 at your text
book (Fowler, 2005), why do
earthquakes occur at the axis of
mid-ocean ridges?
8. Referring to Plate 25 at your text
book (Fowler, 2005), why don't
earthquakes occur at depths
greater than 700 km? Explain your
reasoning.
Similar Question which may be
asked for FINAL
9. The ocean depth at a distance of
1600 km from the Mid-Atlantic
Ridge is 4700 m. (a) Calculate: (i)
the age of the crust at this location
(ii) the mean spreading rate
represented by this age. (b) Is this
a half or a full spreading rate?
10. The width of ocean floor between
the spreading ridge in the South
Atlantic Ocean at 30°S and the
edge of the continental shelves
along the east coast of South
America and the west coast of
southern Africa at 3°S is
approximately 3100 and 2700 km
respectively. Assuming that the
spreading rate on this segment of
the ridge is 38 mm y−1, estimate

3. the maximum age of the sea floor
on either side of the South
Atlantic.
11.