Chapter 21 Flashcards Preview

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Flashcards in Chapter 21 Deck (24):
1

Subduction

The process in which one tectonic plate Bends and descends beneath another plate at a convergent boundary

2

Continental drift

A hypothesis by Alfred Wegener that the worlds continents are mobile and have moved to their present positions as the ancient supercontinent Pangaea broke apart

3

Surface wave

A type of seismic wave that travels along earth surface

4

Isostasy

The process by which oceanic crust and continental crust come into vertical equilibrium with respect to the mantle, the dense oceanic crust sits lower in the mantle than the less dense continental crust

5

Divergent plate boundary

A plate boundary where lithospheric plates move away from one another-a spreading center; an area of tensional stress where new lithosphere crust is formed

6

Secondary wave

S wave; a transverse body wave that vibrates the material through which it move side to side or up-and-down; it cannot travel through liquids and so does not travel through earth outer core

7

Mantle

The middle layer in earths interior between the crust and the core

8

Asthenosphere

A subdivision of the upper mantle situated below the lithosphere, zone of plastic, easily the phone dropped

9

Syncline

I don't fold in rock with relatively young rocks at the four core; rock age increases with horizontal distance from the fold core

10

Lithosphere

The entire crust plus the rigid portion of the mantle that is above the asthenosphere

11

Anticline

And up fold in rock with relatively old rocks at the fold core; rock age decreases with horizontal distance from the full-color

12

Transform plate boundary

A plate boundary where two plates are sliding horizontally passed each other without appreciable vertical movement

13

Plate tectonics

The theory that earths lithosphere is broken into pieces that move over the asthenosphere; boundaries between plates are where are most earthquakes and volcanoes occur in where the lithosphere is created and recycled

14

Seafloor spreading

The moving apart of two oceanic plates at a rift in the seafloor

15

Core

The central layer of earths interior, divided into an outer liquid core in an inner solid core

16

Paleomagnetism

The natural ancient magnetization and rock that can be used to determine the polarity of earths magnetic field and the rocks location of formation

17

Convergent plate boundary

A plate boundary where tectonic plates move toward one another; an area of compressive stress where lithosphere is recycled into the mantle or shortened by folding and faulting

18

Fault

A fracture along which movement of rock on one side relative to rock on the other side has occurred

19

Earthquake

The shaking or trembling of the ground that happens when rock under earth surface moves or breaks

20

Mohorovicic discontinuity

The crust mantle boundary this marks one of the Depp's where the speed of P waves traveling through earth suddenly increases

21

Crust

Earths outermost layer

22

Body wave

A type of seismic wave that travels through earths interior

23

Rift

A long narrow gap that forms as a result of two plates diverging

24

Primary wave

P-wave; and longitudinal body wave that compresses and expands the material through which it moves