Plate Tectonic Theory

Front 1

plate tectonic theory

Back 1

theory that the lithosphere is divided into tectonic plates that slowly move on top of the asthenospere

Front 2

lithospere

Back 2

cool,ridgid,outermost layer if earth that is divided into enormous pieces called tectonic plates; consist of the crust and the right uppermost part of the mantle

Front 3

asthenospere

Back 3

the soft layer of the mantle below the lithosphere on which the plates move due to convection currents

Front 4

plasticity

Back 4

having characteristics of a solid when still but liquid when in motion

Front 5

convection current

Back 5

the heating and rising and cooling and falling if any liquid substance the mantle has convection. currents which cause the plates to move

Front 6

continental drift

Back 6

the theory that continents were once connected but have drifted apart

Front 7

Alfred wegener

Back 7

meteorologist who postulated the continental drift theory

Front 8

fossil evidence

Back 8

impressions of organisms left in rock layers that indicate the organisms once lived in the area

Front 9

harry hess

Back 9

a geology processed at Princeton university who theorized the process of sea floor spreading

Front 10

sea floor spreading evidence

Back 10

a parallel pattern of rock material found at identical locations on each side of the mid-alantic ridge reveals rock of the same geologic age and polarity

Front 11

magnetic reversal

Back 11

a change in magnetic poles as evidenced by rock layers at points of sea floor spreading

Front 12

divergent boundary

Back 12

the boundary between two tectonic plates moving a way from each others on land creates rift valleys on the sea floor creates new ocean crust

Front 13

convergent boundary with subduction

Back 13

the boundary between two tectonic plates moving. toward each other resulting in volcanic activity when a denser ocean plate subducts below continental plate

Front 14

sunduction

Back 14

a plate is forced below when one plate is denser than another as they converge occurs at continental to oceanic boundaries and oceanic to oceanic boundaries

Front 15

convergent boundary with mountain building

Back 15

a major geological event occurs when continental plates of equal density converge

Front 16

transform boundary

Back 16

the boundary between two plates that slide pass one another sudden shifts result in major geological events such as earthquakes and the release of stored energy

Front 17

ring of fire

Back 17

ring of volcano's around the pacific due to subduction of geological plates in the pacific rim region