Earth Science Flashcards
Lithosphere
the rigid outer part of the earth, consisting of the crust and upper mantle.
Asthenosphere
the upper layer of the earth’s mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.
Mantle
the region of the earth’s interior between the crust and the core, believed to consist of hot, dense silicate rocks (mainly peridotite).
Core
the dense central region of a planet, especially the nickel–iron inner part of the earth.
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
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.
Boundaries
the edges of tectonic plates
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
A plate that creates new land from cooling magma
Oceanic 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
Laurasia
one of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago
Gondwanaland
one of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago
Hotspots
a localised place where an activity occurs
Tremors
vibration on the Earth’s surface caused by an earthquake
Epicentre
the point on the Earth’s centre directly above the site where an earthquake originates
Focus
the point at which an earthquake begins
Triangulation
finding a location by using at least three different sources of detection
Seismograph
an instrument used to detect and measure the intensity of an earthquake
