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Cards In This Set
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What heats up the earth?
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Radioactive decay
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What are Isotopes
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Elements which have the same number protons and electrons but differ in number of neutrons
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Radioactive Decay
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An irreversible change to an unstable isotope which causes it to change in mass number to a different element
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What is half life
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A way to measure the radioactive decay. It measures how long it takes for the number of atoms to be reduced by half
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Two types of Tectonic activity
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Compression and extension
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Compression
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Causes folding action at converging boundaries. Causes folding of rocks at these boundaries. for ex) alpine
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Extension
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Causes faults by rifting. Happens at mid ocean ridges
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What did Wegener propose?
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That all the landmasses were once one great continent called Pangaea and surrounded by one ocean Panthalassa..
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Why did the continents break apart and what happened?
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Due to rift zones between continents causing ocean basins to form
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What is some other evidence for continental drift?
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Same species, same types of rocks, same regions of glaciers and matching mountain regions
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What are lithospheric plates
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Aka tectonic plates which float above the denser asthenosphere.
These slabs have thickness of 40-80km and extends 100-1000skm laterally |
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Oceanic plate
Continental plate |
Thin and dense oceanic lithosphere (60km)
Thick and light continental lithosphere (150km) |
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Describe Divergent boundary
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Located at mid-ocean ridges. The upward movement of hot mantle causes melting, stretching and rifting of a plate
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What does rifting cause?
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Causes the mafic and ultramafic magma to flow out causing new ocean floor to form. The ocean basin gets wider over
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What is the most accepted evidence for sea floor spreading?
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Symmetrical zones (based on similar age) of oceanic basaltic materials
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