Earth's Structure & plates Flashcards
How old is earth
4.5 billion years old
4 structures in interior
Earthquakes, Volcanos, tectonic plates, Tectonic motion
Inner core
made from nickel and iron, 5000 degress, Solid and is hotter than the sun
Mantle
75% melted rock, Asthenosphere, Convention currents
Crust
10-70km,
Continental crust
Granite and andersite, light coloured, low density, Silica and aluminium, Older, Thicker
Oceanic crust
Basalt, Dark, Dense, Silica and magnesium, younger, Thinner
Continental drift
Theory that the earth is divided into tectonic plates that float on the mantle
Continental drift movements
Crash into, Pull apart, Rub off eachother
Continental drift features
Oceanic trenches, fold mountains, earthquakes
How many tectonic plates are there
7
What do tectonic plates move on
Thermal convection currents
Where does hot magma from the core rise to
Asthenosphere
Where are younger rocks found
plate boundaries
Where are older rocks found
Ocean edges
What was the original continent called
Pangaea
What is continental drift
Theory that the earths crust is divided up into tectonic plates that float on the mantle
What do plates move on
Thermal convection currents
Give 3 examples that prove the theory of Continental drift
Fossils, matching rocks and matching edges of continents
What is a divergent or constructive plate boundary
Plates that separate
What is a convergent or destructive plate boundary
Plates that collide
What is a transform plate boundary
Plates that slide of one another
Give a process of constructive plate boundary
Sea floor spreading, rifting
Give a process of destructive plate boundary
Subduction
Give a feature and location of sea floor spreading
Mid ocean ridge, Atlantic Ridge
Give a feature and location of subduction
Island arc, Japan
Give a feature and location of Transforming plate boundaries
Fault line, San Andreas
Give 2 examples of why we know Ireland has been ‘on the move’
Variety of rocks, Crust welded
