4.1 Plate Tectonics Flashcards
What is the name of the scientist who thought the continents where joined together
Alfred Wegener
What is the supercontinent called
P,angaea
when did scientist start maping the ocean floor.
1980s
Define the big mid-Atlantic ridge
It is a big underwater mountain range in the middle of the Atlantic ocean
What was Harry Hess idea about sea floor spreading
He said that new ocean floor was being made at the mid Atlantic ridge
Define sea floor spreading
It is the process in which the new floor pushes outwards making the old floor move away (this also makes the earth move)
Define lithosphere
There is energy trying to escape from the sun but there is a strong layer stopping it called lithosphere
And it is the earth hard outer layer
what is lithosphere made of
It is made of the earths thin outer layer(the crust) and a bit of the top part of mantle
Convection currents
This is a circular movement of plates rising when hot and sinking when cool
Define plate tectonics
It is the process in which plates sit on top of the mantle and because of the mantle movement the plates move along and make a process called plate tectonics
Name the two types of tectonic plates and divine them
Oceanic Plates: it is made of ocean crust called ‘sima’ because it is made of silicon and magnesium
Continental plates:continental crust called ‘sial’ because its made of silicon and aluminium
Define convergent boundaries
When two tectonic plates push against each other this is called subduction
Define Divergent boundaries
It is when two plates push apart this is called rift
Define Transform boundaries
This is when plates slide past each other this is called faults
Define seismic activity
It is frequency of earthquakes and it is the greatest along plate boundaries
Define rock cycle
It is the process of transforming and renewal of earths crust and also creates mountain ranges
Define plates
Are cracked pieces of lithosphere and they can be as big as continets
