Chapter 17 p375 Plate Tectonics Review 1-25
Alex Chen
Galloway/P5
June 4th, 2003
1: Isostasy is a model stating that the Earth’s solid crust is floating on a fluid mantle.
2: A hot spot is a place where great amounts of heat are rising in the mantle.
3: A mid-ocean ridge is a giant mountain range in the middle of an ocean.
4: Subduction is a process in which one plate is thrust downward into the mantle beneath
another.
5: The asthenosphere is a soft layer of partially molten rock in the upper mantle.
6: A plate is a huge segment of the lithosphere.
7: An island arc is a string of volcanic islands bordering on an ocean trench.
8: Ocean trenches are deep, V-shaped valleys in the sea floor.
9: A rift is a deep, narrow crack that splits the crust of some mid-ocean ridges.
10: A convergent boundary is the place where two plates meet.
11: The youngest rocks on the sea flood are found in rifts in the mid-ocean ridges.
12: Alfred Wegener proposed the theory of continental drift.
13: According to plate tectonics, the Earth’s lithosphere is divided into several huge,
moving pieces.
14: Scientists believe that the sea floor is constantly being created or destroyed.
15: Convergent plate boundaries are places where two plates moving towards each other
collide.
16: The boundaries at which mid-ocean ridges are located are divergent.
17: Plate boundaries are the sites of earthquakes, volcanic eruptions, and mountain
building.
18: Matching rock formations on facing edges of continents, widely separated fossils of
identical plants and animals, and evidence of glaciers near the equator provide evidence
of continental drift. However, undersea volcanoes do not provide evidence for continental
drift.
19: Most volcanoes along continental borders are the result of melting of the lithosphere
due to subduction in a nearby trench.
20: The driving force behind plate motion is thought to be heat currents in the mantle.
21: The lithosphere is made up of huge segments called plates.
22: The Earth’s plates float over a partly molten layer of Earth called the asthenosphere.
23: Three early models explaining crustal movements that led to the theory of plate
tectonics are sea-floor spreading, continental drift, and isostasy.
24: The Earth’s plates move due to convection plates in the mantle, which cause the
mantle to move the plates above.
25: As the Earth’s plates move, they carry continental and oceanic crust, as well as
whatever is above that crust.