Earth Science Flashcards
seismic waves
waves of energy that travel through the Earth’s crust, caused by earthquakes
continental drift
movement of the plates of the Earth’s crust in relation to each other
Pangaea
a super-continent that existed about 225 million years ago. All of the landmasses that existed at this time were joined together to form this super-continent.
Panthalassa
the vast sea surrounding the supercontinent of Pangaea
plate tectonics
the theory concerning the movement of the continental plates
mantle
thick layer inside the Earth, below the crust. Most of the mantle is solid rock, although the upper part is molten rock called magma.
convection current
circular movement that occurs when warmer, less dense fluid particles rise and cooler, denser fluid particles sink
continental crust
the plates of the Earth’s crust that make up the land
oceanic crust
one of the types of crust that makes up the Earth’s outer layer. Oceanic crust is thinner than continental crust and made up of dense, heavy rocks such as basalt.
subduction
process in which two tectonic plates push against each other, and oceanic crust sinks below the less dense continental crust
destructive plate boundaries
a convergent boundary where two plates collide
constructive plate boundaries
plate that creates new land from cooling magma
ocean ridges
an area where the tectonic plates move apart, allowing magma from the mantle to rise, forming underwater volcanoes and creating new oceanic crust as it is cooled and solidified by sea water
conservative plate boundaries
boundaries between sliding plates, like the San Andreas Fault in the United States
gondwanaland
one of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago
hotspot
a localised place where an activity occurs
folding
buckling of rocks caused when rocks are under pressure from both sides