Plate Tectonic Theory Flashcards
What is the Earth’s crust made up of?
A number of large plates that are moving in constant, slow motion.
What moves the plates?
Convection currents in the mantle
What drives the convection currents?
The source of the heat is the radioactive decay happening deep in the Earth.
What are the ocean floors constantly doing?
They are continually moving, spreading from the centre and sinking at the edges.
What happens at the edge of these plates (plate boundaries)?
Earthquakes and volcanoes occur.
What is Jigsaw Fit?
The idea that some continents fit together like a geological puzzle. All the rocks were formed when the land was a single continent – Pangea, until 200 million years ago when they started to seperate.
What is Continental Drift?
The idea that continents are slowly shifting their positions.
Who came up with the idea of Continental Drift/Jigsaw Fit?
Alfred Wegener
What are Convection Currents?
Slow yet extremely powerful movements of volcanic rock in the mantle. The magma is heated to 5000°C in the mantle and rises to the crust where they cool and sink only to be heated again. The process continues. This was powerful enough to move the earth’s plates
