Details

Title: Chapter 19 - Plate Tectonics

Description: Midterm Number IV

Total Flash Cards: 16

Created: 12/05/2009 18:51:15

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Additional Geology Flashcards

Cards in this set:

Term
plate tectonics
 Definition
Earth's surface is divided into a few large, thick plates that move slowly and change in size.
Term
Continental drift
 Definition
idea that continents move freely over Earth's surface, changing their positions relative to one another.
Term
sea floor spreading
 Definition
a hypothesis that the sea floor forms at the crest of the mid oceanic ridge, then moves horizontally away from the ridge crest toward an oceanic trench.
Term
polar wandering
 Definition

aparent movement of the poles

ancient poles were in different positions than the present poles.
Term
subduction
 Definition
sliding of the sea floor beneath a continent or island arc
Term
convection
 Definition
a circulation pattern driven by the rising of hot material and the sinking of cold material
Term
plate
 Definition
a large, mobile slap of rock that is part of earth's surface.
Term
lithosphere
 Definition
plates are composed of this relatively rigid outer shell of Earth
Term
asthenosphere
 Definition
a zone of low seismic wave velocity that behaves in a ductile manner because of increased temperature and pressure
Term
divergent plate boundary
 Definition
boundary between plates that are moving apart
Term
convergent plate boundary 
 Definition
lies between plates that are moving toward each other
Term
transform plate boundary
 Definition
one at which two plates move horizontally past each other
Term
transform fault
 Definition
portion of fracture zone between two offset portions of ridge crest
Term
island arc
 Definition
curved line of volcanoes that form a string of islands parallel to the oceanic trench
Term
magmatic arc
 Definition
both island arcs at sea and for belts of igneous activity on the edges of continents
Term
mantle plumes
 Definition
narrow columns of hot mantle rock that rise through the mantle, much like smoke rising from a chimney