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22 terms

Plate Tectonics and Physical Hazards

pg. 14-33 Ch. 2
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asthenosphere
part of earth's mantle below the lithosphere that behaves in a plastic manner. The rigid and brittle lithosphere moves over it.
collision zone
zone of convergence between two lithospheric plates.
continental drift
gradual movement of continents as oceans spread and separate.
convergent boundaries
tectonic plate boundary along which two plates come together by either subduction or continent- continent collision.
divergent boundaries
spreading plate boundary such as a mid-oceanic ridge.
hotspot volcanoes
isolated volcano, typically not on a lithospheric plate boundary, but lying above a plume or hot column of rock in Earth's mantle.
hypothesis
proposal to explain a set of data or information, which may be confirmed or disproved by further study.
isostacy
lower-density crust floats in Earth's higher density mantle. Also called isostatic equilibrium.
lithosphere
rigid outer rind of Earth approximately 60 to 100 or so kilometers thick; it forms the lithosphereic plates.
magnetic field
area around a magnet in which magnetism is felt.
mantle
thick layer of material below the thin crust and above Earth's core. Mostly peridotite in composition in its upper part. Its density is 3.2 or 3.3 g/cm ^3 in the lower part.
mid-oceanic ridge
a high-standing rift or spreading zone in an ocean-ex. the mid-Atlantic ridge or the east pacific rise.
Pangaea
...super continent that began to beak up to form today's continents 225 million years ago.
plate tectonics
...theory that lithospheric plates move relative one to another. some collide , some pull apart, and some slide past each other. these movements cause earthquakes, volcanoes and mountains to build. A wide range of data supports all of this.
rift zones
...spreading zone on the flank of a volcano from which lavas erupt.
scientific method
...used by scientists to solve problems.
seafloor spreading
...oceanic crust that spreads apart as lithospheric plates separate.
subduction zone
...convergent boundary along which lithospheric plates come together and one descends beneath the other. often ocean floor descending beneath continent.
plate tectonics
...lithosphere is made up by big blocks
theory
...scientific explanation for a broad range of facts that have been confirmed through extensive tests and observations.
transform boundary
...boundary marked by a transform fault.
trenches
...elongate depression in the ocean floor at a subduction zone between two tectonic plates and most commonly at the edge of an active continental margin. Most are at the margins of the Pacific ocean.