Chapter 4.2 Flashcards

Front 1

plate tectonics

Back 1

a theory developed from the continental drift and seafloor spreading. it describes continental movement and proposes a possible explanation of why and how continents move. Lithosphere is made up of plates that float on the asthenosphere and that the plates possible are moved by convection currents.

Front 2

oceanic crust

Back 2

formed from the material on the ocean floor and is one of the two types of earth's crust

Front 3

continental crust

Back 3

makes up the continental landmasses and is one of the two types of earth's crust

Front 4

lithosphere

Back 4

the oceanic and continental crust and the rigid upper mantle make up this. forms the thin outer shell of the earth

Front 5

asthenosphere

Back 5

beneath the lithospher. a layer of plastic rock that is solid rock that slowly flows(putty) when under pressure

Front 6

divergent boundary

Back 6

two plates moving away from each other. found on the ocean floor

Front 7

rift valley

Back 7

in the center of the mid-ocean ridge is a narrow valley formed as the plates separate.

Front 8

convergent boundary

Back 8

the direct collision of one plate with another. as seafloor spreading pulls plates apart at one boundary those plates push into neighboring plates at other boundaries

Front 9

subducted

Back 9

forced under the less dense continental crust

Front 10

subduction zone

Back 10

the region along a plate boundary where one plate moves under another plate

Front 11

ocean trench

Back 11

deep valley in the ocean floor that forms along subduction zone

Front 12

island arc

Back 12

part of the subducted plate melts and the resulting molten rock rises to the surface along the trench to form a chain of volcanic islands

Front 13

transform fault boundary

Back 13

forms where two plates are grinding past each other

Front 14

convection

Back 14

the transfer of heat through the movement of heated fluid material. it causes the movement of lithospheric plates

Front 15

convection current

Back 15

the cycle of warm water rising and cool water sinking to replace it