Tectonics. Flashcards
What are the four major layers of the Earth’s structure?
Inner core, outer core, mantle and crust.
What layer is the thickest?
Mantle.
Which two layers are entirely solid?
Crust and inner core.
What are the two types of crust?
Continental and oceanic.
Which type of crust is more dense? Why is this significant?
Oceanic - when the two meet, the oceanic plate subducts under the continental plate as it is more dense.
What is the name of the process that causes the earths tectonic plates to move?
Convection currents.
How many types of plays boundary are there?
Convergent (continental-oceanic), collision (continental-continental), divergent and conservative.
What direction do the plates move in at convergent plate boundaries?
Towards each other.
True or false? Volcanoes occur at conservative plate boundaries.
False - at conservative plate boundaries, there is no opportunity for magma to reach the surface as the plates are moving alongside each other.
Explain two characteristics of a sheild volcano.
Sheild volcanoes form at divergent plate boundaries. They are low in height and feature a wide bases with gentle slopes (shaped like a sheild) - this is due to non viscous lave which can travel over great distances before cooling and solidifying.
Explain two characteristics of a composite volcano?
Composite volcanoes form at convergent plate boundaries. They are typically more cone- shaped and feature much steeper sides than sheild volcanoes.
What is a hotspot?
It is literally a ‘hotspot’ on the earths surface, often found in the middle of a tectonic plate.
