What substance was able to show previous orientations of Earth's magnetic field?
a. Magma
b. Basalt
c. Magnetite
d. Magnesium
ANS: C
Magnetite is in the mantle. When new crust is formed, the magnetite is in that crust. As it cools, it
points in the direction of the current magnetic field of the Earth. This allowed scientists to determine
the direction of magnetic fields throughout history. Information can be found in the section The
Confirmation of Plate Tectonics
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