Introduction to Geology

Introduction to Geology

Quiz 5 - Earth's Structure and Plate Tectonics

Questions 1 to 9 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.
1. Which letter is the Asthenosphere?
2. Which letter is the Atmosphere?
3. Which letter is the Inner Core?
4. Which letter is the Crust?
5. Which letter is the Lithosphere?
6. Which letter is the Mantle?
7. Which letter is the Mesosphere?
8. Which letter is the Oceans?
9. Which letter is the Outer Core?

10. 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

11. In what region of the Earth do all earthquakes take place?
a. crust
b. mantle
c. lithosphere
d. asthenosphere

12. Based on geophysical studies, what part of the inner layers of the Earth is thought to consist entirely of liquid metal (mostly a mixture of iron and nickel)?
a. mantle
b. asthenosphere
c. outer core
d. inner core

13. 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 region, and vice versa.
d. when the Earth suddenly flips (turns over) on its rotational axis. 

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

16. Fossils of marine organisms found at high elevation in mountain ranges are believe to suggest:
a) sea level was once higher than the mountains ranges around the planet.
b) the rock in these mountains were once below sea level and were later uplifted.
c) the fossils were organisms that live in mountain lakes.
d) mountains only form in ocean basins.

17. This extensive region that surrounds the Pacific Ocean basin described by early explorers is both a major earthquake zone and volcano zone.
a. Ring of Faulty Volcanoes
b. Ring of Fire
c. Pacific Island Arc
d. The Marianas Trench

18. 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.

19. Why was the Theory of Continental Drift (proposed by Alfred Wegener in 1912) rejected by the Scientific Community at that time?
a) There were no matching fossils on different continents on opposite sides of the ocean basins.
b) The shapes of continents do not appear to fit like a jigsaw puzzle.
c) There are no matching rocks and mountain ranges of similar ages on different continents.
d) There was no known mechanism capable of moving continents.
e) All of the above.

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

21. Investigations using the science of paleomagnetism indicate, for example, 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 (even reversed) many times in the past.
d. the continents have moved over time.
e. all of the above.

22. Geologic mapping shows that bedrock on all continental landmasses around the world range in ages that are exceeding old, in many cases, billions of years in some locations. 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

23. A mid-ocean ridge is an example of what type of plate boundary?
a. convergent zone
b. divergent zone
c. transform zone
d. subduction zone

24. Which feature is NOT an example of a plate tectonic convergence region on the Earth today?
a. the Himalayas
b. Iceland on the Mid-Atlantic Ridge
c. Japan
d. the Andes
e. The Aleutian Island Chain

23. At what type of plate boundary are most continental mountains and volcanic island arcs formed?
a. divergent boundary
b. passive continental margin
c. convergent boundary
d. transform boundary

25. Almost all deep-focus earthquakes occur along or near what type of plate boundary?
a. convergent boundary
b. passive margin
c. transform boundary
d. divergent boundary

26. Which type of plate boundary is in the southern coastal California region?
a. passive margin
b. divergent boundary
c. convergent boundary
d. transform boundary

27. Which of these describes the current theory of plate tectonics?
a. it combines elements of continental drift and seafloor spreading.
b. it helps explain the location of volcanoes and earthquakes.
c. it suggests that the lithosphere is divided into pieces, called plates.
d. denser ocean crust sinks below less-dense continental crust along subduction zones.
e. all of the above.

28. A fault-bounded crustal block that has been accreted onto a continent is called a:
a. shield.
b. terrane.
c. mountain belt.
d. craton.

Clues where to find answers.