The Solid Earth - Chapter 6: Testing the Model Flashcards
What is the most persuasive evidence of plate tectonics?
The magnetic field associated with earth
The two poles of the earth’s magnetic fields
north
south
Invisible lines of ____ pass through the earth and extend from one pole to the other
force
The point at which a heated magnetic mineral loses magnetism
Curie point
When iron rich grains cool below their Curie point, they become magnetized in the direction parallel to the _____
existing magnetic field
True or false: once the minerals solidify after cooling below Curie Point, the magnetism they possess will remain “frozen” in this position
true
True or false: rocks “remember” the location of the magnetic poles at the time of their formation and are said to possess fossil magnetism
True
The name for fossil magnetism
paleomagnetism
Where was early evidence of polar wandering found (AKA in what context)?
Scientists found that lava flows with iron content of different ages tended to have varied magnetic alignment
True or false: the plate tectonics theory could explain pole wandering
True
True or false: the earth’s magnetic field periodically reverses polarity
true
When rocks exhibit the same magnetism as the present magnetic field they are said to possess ___ polarity
normal
Rocks that display the opposite magnetism to the current field have ____ polarity
reverse
In the plate tectonics model, what are produced where cold dense slabs of oceanic lithosphere plunge into the mantle?
Deep ocean trenches
As the slab descends further into the asthenosphere, ____ earthquakes are generated
deeper focus
