Earth sciences and Plate Techtonics Flashcards
Three differences between oceanic and continental crust.
Oceanic-7km thick / Continental-70km thick
Oceanic-more dense / Continental-less dense
Oceanic-underwater / Continental-under land mainly.
Two types of crust
Oceanic
Continental
Two areas of earth we study
Lithosphere
asthenosphere
facts about lithosphere
rigid and hard
100km thick
split into techtonic plates
3 facts about asthenosphere
viscous slow moving rock
under tectonic plates
where convection currents occur
how are oceanic plates born and die and how long do they live for
400 million years
born: constructive plate boundaries.
death: destructive plate boundaries by subduction.
how are continental plates born and die and how long do they live for.
1-1.5bn years
born: oceanic turns into them
death: erosion and weathering
two examples of oceanic plates
pacific
nazca
two examples of continental plates
eurasian
african
what are the three sizes of plates
major
minor
micro
describe convection currents
magma heats up and rises towards the crust. this then hits the crust and moves to the side taking the crust with it. it eventually cools and falls back down. this then repeats.
describe ridge push
when plates slope the plate angles to earth increasing the effect of gravity. this speeds up the plate. ridges are created by constructive plate boundaries. plate is pushed from the back.
describe slab pull
when a plate is subducted it angles towards earth increasing gravitational pull. speeding it up. this is pulled from the front.
what are the six continental drift theories.
jigsaw ideas
dinosaur fossils found in locations
magnetic sea floor readings
glaciated landscapes
volcanic landscapes
coal and mineral locations
