Unit 4 Vocab

Question 1

Continental drift

Answer 1

hypothesis that a single large landmass broke up into smaller land masses to form the continents, which then drifted to their present locations

Question 2

puzzle pieces

Answer 2

continents seem to fit together like puzzle pieces if we were to cut and move the shapes from the map

Question 3

mid-ocean ridges

Answer 3

long undersea mountain chain that has a steep, narrow valley at its center, that forms as magma rises from the asthenosphere, and that creates new oceanic lithosphere (sea floor) as tectonic plates move apart

Question 4

sea-floor spreading

Answer 4

the process where new oceanic lithosphere (sea floor) forms as magma rises to Earth’s surface at mid-oceanic ridges and solidifies, as older, existing seafloor moves away from the ridge

Question 5

Paleomagnetism

Answer 5

study of the alignment of magnetic minerals in rock, specifically as it relates to the reversal of Earth’s magnetic poles; also the magnetic properties that rock acquires during formation

Question 6

Normal Polarity

Answer 6

magnetic rocks point N

Question 7

Reversed Polarity

Answer 7

magnetic rocks point S

Question 8

Geomagnetic reversal time scale

Answer 8

scientist arrange the pattern of normal polarity and reversed polarity to create a time scale as recorded by paleomagnetism

Question 9

plate tectonics

Answer 9

theory that explains how large pieces of the lithosphere, called plates, move and change shape

Question 10

Lithosphere

Answer 10

solid, outer layer of Earth that consists of the crust and the rigid upper part of the mantle (sea floor)

Question 11

Asthenosphere

Answer 11

the solid, plastic layer of the mantle beneath the lithosphere

Question 12

Divergent Boundaries

Answer 12

boundary between tectonic plates that are moving apart

Question 13

Convergent boundaries

Answer 13

boundary between tectonic plates that are colliding

Question 14

ocean-continental (subduction zones)

Answer 14

ocean crust is denser so it subducts under the continental

Question 15

continental-continental

Answer 15

both plates are equally or nearly equal in density so neither subducts and we get thickening forming mountains

Question 16

oceanic-oceanic

Answer 16

both very dense so one eventually gives and produces a deep trench and sometimes islands arcs due to production of magma

Question 17

transform boundaries

Answer 17

boundary between tectonic plates that are sliding past each other horizontally

Question 18

Convection

Answer 18

movement of heated material due to differences in density that are caused by differences in temperatures

Question 19

ridge push

Answer 19

as the cooled, older rock slides down the ridge of the slope it exerts a force on the rest of the plate

Question 20

slab pull

Answer 20

as the leading edge of the plate sinks, it pulls the rest of the plate along behind it

Question 21

Cratons

Answer 21

large stable block of the Earth’s crust forming the nucleus of a continent,; these are ancient cores where the modern continents formed

Question 22

shield

Answer 22

rocks within the craton that have been exposed to the surface

Question 23

rifiting

Answer 23

process by which Earth’s crust breaks apart; can occur within continental crust or oceanic crust

Question 24

Terrane

Answer 24

piece of lithosphere that has a unique geologic history and that may be part of a larger piece of lithosphere, such as a continent

Question 25

supercontinent cycle

Answer 25

process by which supercontinents form and break apart over millions of years

Question 26

Pangaea

Answer 26

supercontinent that formed 300 million years ago and that began to break up 200 million years ago

Question 27

Panthalassa

Answer 27

single, large ocean that covered Earth's surface during the time Pangaea existed

Question 28

deformation

Answer 28

bending, tilting, and breaking of Earth's curst; the change in the shape of rock in response to stress

Question 29

Isostasy

Answer 29

condition of gravitational and buoyant equilibrium between Earth's lithosphere and asthenosphere

Question 30

compression

Answer 30

squeezing and shortening of a body

Question 31

Tension

Answer 31

stretching and pulling of a body

Question 32

Shear Stress

Answer 32

distortion of a body by moving parts in opposite directions

Question 33

Strain

Answer 33

any change in a rock's shape or volume caused by stress

Question 34

brittle

Answer 34

response to stress by breaking/fracturing

Question 35

ductile

Answer 35

response to stress through bending/deforming w/o breaking

Question 36

Fold

Answer 36

form of ductile strain in which rock layers bend, usually as a result of compression

Question 37

Anticline

Answer 37

oldest layer is in the center of the fold

Question 38

syncline

Answer 38

fold in which the youngest layer is in the center of the fold

Question 39

monocline

Answer 39

one part of the crust moves up or down relative to another

Question 40

faults

Answer 40

break in a body of rock along which one block slides relative to another; form of brittle strain

Question 41

fault plane

Answer 41

surface or plane along which the motion occurs

Question 42

hanging wall

Answer 42

rock above the fault plane

Question 43

footwall

Answer 43

rock below the fault plane

Question 44

normal faults

Answer 44

fault in which the hanging wall moves downward relative to footwall

Question 45

Reverse Faults

Answer 45

fault in which the hanging wall moves upward relative to footwall

Question 46

thrust faults

Answer 46

reverse fault that occurs at very low angles

Question 47

strike-slip faults

Answer 47

rock on either side of the fault plane slides horizontally in response to shear stress

Question 48

mountain ranges

Answer 48

series of mountains that are closely related in orientation, age, and mode of formation

Question 49

mountain system

Answer 49

group of mountain ranges