Chapter 13 - Drifting Continents: Plate Tectonics

Question 1

pangaea

Answer 1

supercontinent; previously-single large land mass

Question 2

laurasia

Answer 2

landmass that would eventually become North America, Greenland, and Eurasia

Question 3

gondwana

Answer 3

landmass that would eventually become South America, Australia, Africa, India, and Antarctica

Question 4

continental drift

Answer 4

theory by Alfred Lothar Wegener proposing that continents move slowly across Earth’s surface

Question 5

plate tectonics

Answer 5

theory describing the origin, movement, and recycling of lithospheric plates and the resulting landforms

Question 6

subduction

Answer 6

a process in which oceanic lithosphere of one plate bends and dives into the mantle beneath another plate

Question 7

plate boundaries

Answer 7

the place where lithospheric plates meet

Question 8

active continental margin

Answer 8

follows a plate boundary

Question 9

passive continental margin

Answer 9

has a broad sloping continental shelf and does not coincide with a plate boundary

Question 10

ridge push

Answer 10

the process by which magma rising along a mid-ocean ridge lifts oceanic lithosphere and forms a slope

Question 11

mantle drag

Answer 11

caused by convection within the asthenosphere

Question 12

slab pull

Answer 12

the weight of the subducting portion of a plate accelerates plate movement by pulling the plate deeper into the mantle

Question 13

divergent plate boundary

Answer 13

occurs where two plates move apart

Question 14

convergent plate boundary

Answer 14

occurs where two plates move toward each other

Question 15

transform plate boundary

Answer 15

occurs where one plate slips laterally past another

Question 16

decompression melting

Answer 16

the process of melting hot mantle through changes in pressure

Question 17

rift

Answer 17

a region where continental crust is stretching and splitting

Question 18

rift valley

Answer 18

a long valley with volcanoes formed by rifting of continental crust

Question 19

wadati-benioff zone

Answer 19

a sloping pattern of increasingly deep earthquake centers in subduction zones

Question 20

flux melting

Answer 20

the process in which the mantle mixes with seawater and melts into magma

Question 21

continental arcs

Answer 21

long chains of volcanoes that form only on the margins of continents where subduction is occuring

Question 22

accretionary prism

Answer 22

folded mass of sediments and rock that forms during subduction when sediments and rocks on the seafloor are scraped up against the edge of the overriding continent

Question 23

island arc

Answer 23

chain of volcanic islands formed where oceanic lithosphere of one plate is subducting beneath oceanic lithosphere of another plate

Question 24

pacific ring of fire

Answer 24

a zone of volcanically active mountain chains resulting from subduction on the margins of the pacific ocean

Question 25

collision

Answer 25

occurs where the continental crust of two plates converges

Question 26

accreted terrane

Answer 26

a mass of crust that is transported by plate movement and fused onto the margin of a continent

Question 27

hot spots

Answer 27

volcanically active and isolated locations on Earth’s surface that is caused by a vertical column of hot rock (mantle plume) that extends down as far as Earth’s outer core

Question 28

mantle plume

Answer 28

a mostly stationary column of hot rock that extends from deep in the mantle up to the base of the lithosphere

Question 29

fold

Answer 29

a wrinkle in the crust that results from deformation caused by geological stress

Question 30

fault

Answer 30

a fracture or break in the crust where movement and earthquakes occur

Question 31

anticline

Answer 31

a fold in the crust with an archlike ridge

Question 32

syncline

Answer 32

a fold in the crust with a U-shaped dip

Question 33

orogenesis

Answer 33

the building of mountain ranges by any tectonic process

Question 34

orogenic belts

Answer 34

mountain ranges grouped together linearly that forms most commonly along plate boundaries, particularly in areas of collision and subduction