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Earth Movement
Plates of the Earth
Question | Answer |
---|---|
cast fossil | a fossil that forms when a mold is filled in with minerals deposited by water – a three dimensional replica of the organism. |
continent | one of the seven large masses of earth (Asia, Africa, Australia, Europe, North America, South America, and Antarctica). |
continental crust | the layer of crust that contains the continents. |
continental drift | the theory that the continents have moved vast distances around the earth over millions of years to reach their present location. |
convection | the continuous cycle of heating and rising, cooling and sinking. |
convection currents | the circular path of a gas or liquid as it is heated and rises, spreads out, and then cools and sinks. |
core | the earth’s innermost layer. |
crust | the thin, rocky, outermost layer of the earth. |
earthquake | vibrations in the earth’s crust caused by the sudden release of energy due to shifting rocks along a fault. |
erupt | to break through; to force out suddenly and violently. |
fault | a break or crack in the earth’s crust where two plates slide past each other. |
fossil | the remains of an organism that lived long ago, found preserved in rock preserved in rock. |
geology | the study of earth and its history. |
glacier | a huge, slow-moving mass of ice. |
inner core | the innermost layer of the earth which is made of solid metals (high temperatures and high pressure). |
island | land mass surrounded by water. |
lava | magma that comes out of a volcano. |
lithosphere | consists of the crust and upper-part of the mantle that is separated into the tectonic plates. |
magma | the melted rock that makes up the mantle. |
mantle | the thick fluid layer of earth on which the crust floats. |
model | a smaller or larger version of an object used to represent the actual object. |
mold fossil | an imprint left in a rock after the remains of an organism have disintegrated. |
ocean floor | the surface of the earth’s crust beneath the ocean. |
mid-ocean ridge | a mountain range on the ocean floor. |
ocean-floor spreading | the process by which hot magma from the mantle wells up in the boundary between two oceanic plates as they move away from each other – it results in the creation of new crust. |
oceanic crust | the layer of crust beneath the oceans. |
Pangaea | the name for the super-continent that scientists believe existed about 200 million years ago, in which all the present continents were once joined. |
plate | a section of the earth’s crust. |
Ring of Fire | a region of the earth in which many volcanoes and earthquakes occur (encircling the Pacific). |
subduction | the process in which two plates collide and the edge of the denser plate sinks beneath the edge of the less dense plate, then melting back into the mantle. |
trench | a deep, narrow valley in the ocean floor where subduction takes place. |
vibrations | a rapid back and forth movements. |
volcano | an opening in the earth’s crust through which melted rock reaches the earth’s surface. |