Geology Cafe

Oceanography 101

Quiz Questions - Chapter 3 - Structure of the Earth

1) The rigid outer part of the earth, consisting of the crust and upper mantle. is a relatively cool, rigid shell and averages about 100 km in thickness and called the:
a. asthenosphere
b. lithosphere
c. stratosphere
d. cryosphere

2) What is a magnetic field reversal?
a.  when Earth's magnetic field suddenly disappears for short periods of time
b. when Earth's magnetic field suddenly runs east/west instead of south/north 
c. when Earth's magnetic field leaves the south pole and enters the north pole
d. when Earth's magnetic field leaves the north pole and enters the south pole 

3) The alignment of iron-rich minerals in old volcanic lava flows show that:
a. the Earth's magnetic poles may have moved.
b. the Earth's magnetic poles have switched alignment many times in the past.
d. the continents have moved over time.
e. all of the above.

4) The first to arrive at a distant location from an earthquake is:
a. a shear (S) wave.
b. a compression (P) wave.
c. a sound (S) wave.
d. a rupture.
e. none of the above.

Questions 5-13 apply to the Structure of the Earth Diagram below. Note layers on left are classified by chemical properties, right are physical properties.
Structure of the Earth diagram
Match letters (A to J) to features on the Structure of the Earth diagram.
5) Which letter is the Asthenosphere?
6) Which letter is the Atmosphere?
7) Which letter is the Inner Core?
8) Which letter is the Crust?
9) Which letter is the Lithosphere?
10) Which letter is the Mantle?
11) Which letter is the Mesosphere?
12) Which letter is the Oceans?
13) Which letter is the Outer Core?

14) The Mohorovicic discontinuity (or Moho) is:
a. the boundary between granitic continental crust and basaltic oceanic crust.
b. the boundary surface between the earth's crust and the mantle, lying at a depth of about 6–7 miles (10–12 km) under the ocean bed and about 24–30 miles (40–50 km) under the continents.
c. the boundary between earth’s rigid mantle and the liquid core.
d. a fault boundary between two plates in a subduction zone.

15) Isostacy allows continental crust rises above sea level because it is:
a. denser than ocean crust.
b. is mostly basalt in composition compared with ocean crust.
c. contains more granitic rocks than ocean crust.
d. all of the above.

16) This extensive region that surrounds the Pacific Ocean basin is both a major earthquake zone and volcano zone.
a. Ring of Volcanoes
b. Ring of Fire
c. Pacific Island Arc
d. The Marianas Trench

17) The theory of continental drift (proposed by Alfred Wegener in 1912) was supported by what kind of evidence?
a. matching fossils on different continents
b. shapes of continents appear to fit like a jigsaw puzzle
c. matching rocks and mountain ranges on different continents
d. all of the above

18) The most conclusive proof for continental drift was provided by:
a. the coastlines of continents on a world map.
b. evidence of sea-floor spreading.
c. identical fossils and rocks found on two separate continents.
d. changes in climatic patterns.

19) The supercontinent in the continental drift hypothesis was called:
a. Panthalassa.
b. Pangaea.
c. Africana.
d. Pandora.

20) Geologic mapping shows that bedrock on all continental landmasses around the world range in ages that are exceeding old. However, the oldest rocks found in the world’s ocean basins are:
a. about 2 million years.
b. about 20 million years.
c. about 200 million years.
d. about 2 billion years.
e. none of the above.