part 5 plate tectonics review ---pages 42 to 47 ---sfx --fall 2009
section of the Earth's crust ( lithosphere )
idea that has been tested ----but not proven
what is defined as : the constant slow movement of earth's plates b/c of convection currents?
what actions can happen where plates meet?
collide,pull apart , or slide past each other
a break in the Earth's crust
3 types of plate boundaries?
transform, divergent, and convergent
boundary where plates come together ?
boundary where plates pul apart?
boundary where playes slide past each other?
can divergent boundaries occur on land?
yes ---can create rift valleys
when 2 plates collide -- what determines which one will be on top?
density --the less dense plate will go on top
what is more dense --oceanic or continental ?
oceanic ---has more mass in a given volume .... remember the oceans are lower than the continents ------so they must be more dense
the rate at which you fingernails grow ------ is equal to the rate of movement of the earths plates. true or false ??
how long ago did Pangaea break up?
225 milllion yrs ago